Journal articleJournal of Rheology · January 1, 2026
Understanding the structure and dynamics of ring or cyclic polymers is a long-standing challenge in polymer science, with important implications for emerging biological phenomena such as chromosome territories. This Perspective article provides a comprehen ...
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Journal articleMacromolecules · December 23, 2025
Polymer networks are complex materials with a broad distribution of molecular states, making it challenging to establish direct connections between the structure of individual network components and macroscopic material behavior. Recent advancements in mec ...
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Journal articleACS macro letters · December 2025
Both polymer size and chain elasticity depend on long-range bond correlations, which determine the chain Kuhn length. These correlations are gradually cut off with increasing externally applied force or polymer confinement, thereby decreasing the effective ...
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Journal articleACS central science · October 2025
The stretchability (ability to be elongated) and toughness (capacity to absorb energy before breaking) of polymer network materials, such as elastomers and hydrogels, often determine their utility and lifetime. Direct correlations between the molecular beh ...
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Journal articleMacromolecules · September 9, 2025
The stochastic nature of polymers poses a challenge for developing machine-readable molecular representations, especially for coarse-grained computational models of materials. BigSMILES, a line notation that represents stochastic graphs, addresses this iss ...
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Journal articleMacromolecules · August 2025
Pressure differentials across polymer solutions cause fluid flow. We develop a theory for the spatial variation of polymer concentration in solutions under steady flow between two interfaces permeable to the solvent but not to the polymer. The balance betw ...
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Journal articleMacromolecules · July 2025
In the present work, we investigate the nonlinear shear rheology of unentangled polymer melts. We use linear polystyrenes with molar mass of 10 kg/mol, 20 kg/mol, or 30 kg/mol. The measurements of shear and normal stress are performed using cone-and-partit ...
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Journal articleNature Sustainability · June 1, 2025
Natural rubber has many uses in a variety of industries, enabled by ‘crosslinking’ between its tangled polymers, which creates elasticity. But rubber can crack and suffer fatigue. It is now shown that reducing the crosslink density in highly entangled natu ...
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Journal articleNature materials · April 2025
The scission of chemical bonds in materials can lead to catastrophic failure, with weak bonds typically undermining the materials' strength. Here we demonstrate how weak bonds can be leveraged to achieve self-strengthening in polymer network materials. The ...
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Journal articleJournal of the mechanics and physics of solids · February 2025
The design and functionality of polymeric materials hinge on failure resistance. While molecular-level details drive crack evolution in polymer networks, the connection between individual chain scission and bulk failure remains unclear and difficult to pro ...
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Journal articlePhysical review letters · September 2024
Polymers are an effective test bed for studying topological constraints in condensed matter due to a wide array of synthetically available chain topologies. When linear and ring polymers are blended together, emergent rheological properties are observed as ...
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Journal articleAdvanced materials (Deerfield Beach, Fla.) · June 2024
The advent of covalent adaptable networks (CANs) through the incorporation of dynamic covalent bonds has led to unprecedented properties of macromolecular systems, which can be engineered at the molecular level. Among the various types of stimuli that can ...
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Journal articleProceedings of the National Academy of Sciences of the United States of America · May 2024
In mammalian cells, the cohesin protein complex is believed to translocate along chromatin during interphase to form dynamic loops through a process called active loop extrusion. Chromosome conformation capture and imaging experiments have suggested that c ...
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Journal articlebioRxiv · January 26, 2024
In mammalian cells, the cohesin protein complex is believed to translocate along chromatin during interphase to form dynamic loops through a process called active loop extrusion. Chromosome conformation capture and imaging experiments have suggested that c ...
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Journal articleACS macro letters · December 2023
The fracture of polymer networks is tied to the molecular behavior of strands within the network, yet the specific molecular-level processes that determine the mechanical limits of a network remain elusive. Here, the question of reactivity-guided fracture ...
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Journal articleScience advances · December 2023
Strain-induced crystallization (SIC) prevalently strengthens, toughens, and enables an elastocaloric effect in elastomers. However, the crystallinity induced by mechanical stretching in common elastomers (e.g., natural rubber) is typically below 20%, and t ...
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Journal articleProceedings of the National Academy of Sciences of the United States of America · December 2023
Fibrous networks formed by biological polymers such as collagen or fibrin exhibit nonlinear mechanical behavior. They undergo strong stiffening in response to weak shear and elongational strains, but soften under compressional strain, in striking differenc ...
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Journal articleMacromolecules · July 25, 2023
An equilibrium statistical mechanical theory for the formation of reversible networks in two-component solutions of associative polymers is presented to account for the phase behavior due to hydrogen-bonding, metal-ligand, electrostatic, or other pairwise ...
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Journal articleACS macro letters · July 2023
Extending polymer chains results in a positive chain tension, fch, primarily due to conformational restrictions. At the level of individual bonds, however, tension, fb, is either negative or positive and depends o ...
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Journal articleProceedings of the National Academy of Sciences of the United States of America · June 2023
The active loop extrusion hypothesis proposes that chromatin threads through the cohesin protein complex into progressively larger loops until reaching specific boundary elements. We build upon this hypothesis and develop an analytical theory for active lo ...
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Journal articleScience (New York, N.Y.) · June 2023
The mechanical properties of covalent polymer networks often arise from the permanent end-linking or cross-linking of polymer strands, and molecular linkers that break more easily would likely produce materials that require less energy to tear. We report t ...
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Journal articleACS polymers Au · April 2023
The topological constraints of nonconcatenated ring polymers force them to form compact loopy globular conformations with much lower entropy than unconstrained ideal rings. The closed-loop structure of ring polymers also enables them to be threaded by line ...
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Journal articleMacromolecules · March 28, 2023
We present a modified Lake-Thomas theory that accounts for the molecular details of network connectivity upon crack propagation in polymer networks. This theory includes not only the energy stored in the breaking network strands (bridging strands) but also ...
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Journal articleACS macro letters · March 2023
Slide-ring gels are polymer networks with cross-links that can slide along the chains. In contrast to conventional unentangled networks with cross-links fixed along the chains, the slide-ring networks are strain-softening and distribute tension much more u ...
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Journal articlePhysiological reviews · October 2022
The mucus clearance system is the dominant mechanical host defense system of the human lung. Mucus is cleared from the lung by cilia and airflow, including both two-phase gas-liquid pumping and cough-dependent mechanisms, and mucus transport rates are heav ...
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Journal articleNature communications · June 2022
Confinement of fibrous hydrogels in narrow capillaries is of great importance in biological and biomedical systems. Stretching and uniaxial compression of fibrous hydrogels have been extensively studied; however, their response to biaxial confinement in ca ...
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Journal articleMacromolecules · May 10, 2022
We have developed a scaling theory of the elasticity of swollen and deswollen polymer networks. The elasticity of unentangled networks is primarily due to cross-links, and the elasticity of entangled networks is due to trapped entanglements. In preparation ...
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Journal articleScience advances · April 2022
Cystic fibrosis (CF) is characterized by abnormal transepithelial ion transport. However, a description of CF lung disease pathophysiology unifying superficial epithelial and submucosal gland (SMG) dysfunctions has remained elusive. We hypothesized that bi ...
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Journal articleMacromolecules · April 2022
We rationalize the unusual gas transport behavior of polymer-grafted nanoparticle (GNP) membranes. While gas permeabilities depend specifically on the chemistry of the polymers considered, we focus here on permeabilities relative to the corresponding pure ...
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Journal articleSoft matter · February 2022
A scaling model of the concentration profiles of both condensed and free counterions is presented for solutions of spherical and cylindrical charged nanoparticles of different charge valences, nanoparticle sizes, and salt concentrations. The distribution o ...
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Journal articleMacromolecules · November 9, 2021
For strongly charged polyelectrolytes in salt-free solutions, we use molecular dynamics simulations of a coarse-grained bead-spring model to calculate overlap concentrations c∗ and chain structure for polymers containing N = 10 to 1600 monomers. Over much ...
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Journal articleACS nano · October 2021
Two different classes of hairy self-suspended nanoparticles in the melt state, polymer-grafted nanoparticles (GNPs) and star polymers, are shown to display universal dynamic behavior across a broad range of parameter space. Linear viscoelastic measurements ...
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Journal articleScience (New York, N.Y.) · October 2021
The utility and lifetime of materials made from polymer networks, including hydrogels, depend on their capacity to stretch and resist tearing. In gels and elastomers, those mechanical properties are often limited by the covalent chemical structure of the p ...
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Journal articleMacromolecules · August 2021
The diffusion of monomerically thin nanorods in polymer melts is studied by molecular dynamics simulations. We focus on the systems where chains are long enough to screen the hydrodynamic interactions such that the diffusion coefficient D∥
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Journal articleACS polymers Au · August 2021
Recent experiments on melts of spherical nanoparticles (NPs) densely grafted with polymer chains show enhanced gas transport relative to the neat polymer (without NPs). As a means of understanding this unexpected behavior, we consider here the simpler case ...
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Journal articleJournal of rheology · July 2021
We present a comprehensive experimental rheological dataset for purified entangled ring polystyrenes and their blends with linear chains in nonlinear shear and elongation. In particular, data for shear stress growth coefficient, steady-state shear viscosit ...
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Journal articleJournal of the American Chemical Society · April 2021
Mechanochemical reactions that lead to an increase in polymer contour length have the potential to serve as covalent synthetic mimics of the mechanical unfolding of noncovalent "stored length" domains in structural proteins. Here we report the force-depend ...
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Journal articleChemical reviews · April 2021
Polymer networks are complex systems consisting of molecular components. Whereas the properties of the individual components are typically well understood by most chemists, translating that chemical insight into polymer networks themselves is limited by th ...
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Journal articleMacromolecules · March 23, 2021
Steady-state shear viscosity (γ˙) of unconcatenated ring polymer melts as a function of the shear rate γ˙ is studied by a combination of experiments, simulations, and theory. Experiments using polystyrenes with Z ≈ 5 and Z ≈ 11 entanglements indicate weake ...
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Journal articleJournal of the American Chemical Society · March 2021
The fracture of rubbery polymer networks involves a series of molecular events, beginning with conformational changes along the polymer backbone and culminating with a chain scission reaction. Here, we report covalent polymer gels in which the macroscopic ...
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Journal articleMacromolecules · February 2021
We develop a scaling theory that predicts the dynamics of symmetric and asymmetric unentangled liquid coacervates formed by solutions of oppositely-charged polyelectrolytes. Symmetric coacervates made from oppositely-charged polyelectrolytes consist of pol ...
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Journal articleACS nano · December 2020
Polymer membranes are critical to many sustainability applications that require the size-based separation of gas mixtures. Despite their ubiquity, there is a continuing need to selectively affect the transport of different mixture components while enhancin ...
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Journal articleACS nano · November 2020
The structure of neat melts of polymer-grafted nanoparticles (GNPs) is studied via coarse-grained molecular dynamics simulations. We systematically vary the degree of polymerization and grafting density at fixed nanoparticle (NP) radius and study in ...
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Journal articleMacromolecules · November 2020
A scaling model for the structure of coacervates is presented for mixtures of oppositely-charged polyelectrolytes of both symmetric and asymmetric charge-densities for different degrees of electrostatic strength and levels of added salt. At low electrostat ...
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Journal articleIEEE transactions on bio-medical engineering · August 2020
ObjectiveEthanol ablation, the injection of ethanol to induce necrosis, was originally used to treat hepatocellular carcinoma, with survival rates comparable to surgery. However, efficacy is limited due to leakage into surrounding tissue. To reduc ...
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Journal articleMacromolecules · August 2020
Polymer-tethered nanoparticles (NPs) are commonly added to a polymer matrix to improve material properties. Critical to the fabrication and processing of such composites is the mobility of the tethered NPs. Here we study the motion of tethered-NPs in unent ...
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Journal articleMacromolecules · March 2020
We combine linear viscoelastic measurements and modelling in order to explore the dynamics of blends of the same-molecular-weight ring and linear polymers in the regime of the low volume fraction (0.3 or lower) of the ring component. The stress relaxation ...
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Journal articlePhysical review letters · January 2020
Molecular dynamics simulations confirm recent extensional flow experiments showing ring polymer melts exhibit strong extension-rate thickening of the viscosity at Weissenberg numbers Wi≪1. Thickening coincides with the extreme elongation of a minority popu ...
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Journal articlePhysical review letters · May 2019
Featured Publication
In the melt state at equilibrium, entangled nonconcatenated ring macromolecules adapt more compact conformations compared to their linear analogs and do not form an entanglement network. We show here that, when subjected to uniaxial stretching, they exhibi ...
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Journal articleMacromolecules · April 9, 2019
Featured Publication
We present a conceptual framework for adding molecular details of chain extension and force-coupled bond dissociation to the Lake-Thomas model of tear energy in rubbery crack propagation. Incorporating data reported from single-molecule force spectroscopy ...
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Journal articleAngewandte Chemie (International ed. in English) · March 2019
Featured Publication
Chiral packing of ligands on the surface of nanoparticles (NPs) is of fundamental and practical importance, as it determines how NPs interact with each other and with the molecular world. Herein, for gold nanorods (NRs) capped with end-grafted nonchiral po ...
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Journal articleMacromolecules · February 2019
A scaling theory is developed for the motion of a polymer-tethered nanoparticle (NP) in an unentangled polymer melt. We identify two types of scaling regimes depending on the NP diameter d and the size of a grafted polymer chain (tail) R
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Journal articleProceedings of the National Academy of Sciences of the United States of America · December 2018
Clearance of intrapulmonary mucus by the high-velocity airflow generated by cough is the major rescue clearance mechanism in subjects with mucoobstructive diseases and failed cilial-dependent mucus clearance, e.g., subjects with cystic fibrosis (CF) or chr ...
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Journal articleMacromolecules · December 2018
We develop a scaling theory and perform molecular dynamic simulations of weakly interacting coacervates with electrostatic interaction energy per charge less than thermal energy kT. Such liquid coacervates formed by oppositely charged polyelectrolyt ...
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Journal articleMacromolecules · November 2018
Hydrogels formed by polyelectrolyte complexation (PEC) of oppositely charged biopolymers, free of any chemical additives, are promising biomaterials. In this work, the mechanical behavior of hydrogels consisting of positively charged chitosan and negativel ...
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Journal articlePhysical Review Letters · 2018
We use molecular simulations to probe the local viscoelasticity of an entangled polymer melt by tracking the motion of embedded nonsticky nanoparticles (NPs). As in conventional microrheology, the generalized Stokes-Einstein relation is employed to extract ...
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Journal articleAdvanced Materials · 2017
An experiment has demonstrated that genetically engineered unstructured proteins with covalent and reversible crosslinking (due to metal coordination and hydrophobic interactions) yield hydrogels with extremely high strength, toughness, stretchability, and ...
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Journal articleNature Chemistry · 2017
A programmable model of membraneless organelles comprised of intrinsically disordered proteins (IDPs) containing sequences of low complexity has now been developed. The rules governing the assembly of archetypal IDPs into biologically inspired mixed, layer ...
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Journal articleSoft Matter · 2017
Randomly branched polymer chains (or trees) are a classical subject of polymer physics with connections to the theory of magnetic systems, percolation and critical phenomena. More recently, the model has been reconsidered for RNA, supercoiled DNA and the c ...
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Journal articleMacromolecules · 2017
The motion of nanoparticles (NPs) in en-tangled melts of linear polymers and nonconcatenated ring polymers are compared by large-scale molecular dynamics simulations. The comparison provides a paradigm for the effects of polymer architecture on the dynamic ...
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Journal articleNature Communications · 2017
The ability to precisely control the transport of single DNA molecules through a nanoscale channel is critical to DNA sequencing and mapping technologies that are currently under development. Here we show how the electrokinetically driven introduction of D ...
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Journal articleBiomacromolecules · 2017
The details of how the mucus hydrogel forms from its primary structural component, mucin polymers, remain incompletely resolved. To explore this, we use a combination of macrorheology and single particle tracking to investigate the bulk and microscopic mec ...
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Journal articleProceedings of the National Academy of Sciences · 2017
Understanding of the conformational ensemble of flexible polyelectrolytes, such as single-stranded nucleic acids (ssNAs), is complicated by the interplay of chain backbone entropy and salt-dependent electrostatic repulsions. Molecular elasticity measuremen ...
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Journal articleNature Materials · 2016
Polymer gels are the only viable class of synthetic materials with a Young’s modulus below 100 kPa conforming to biological applications, yet those gel properties require a solvent fraction. The presence of a solvent can lead to phase separation, evaporati ...
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Journal articleScience Advances · 2016
Bottlebrushes are fascinating macromolecules that display an intriguing combination of molecular and partic-ulate features having vital implications in both living and synthetic systems, such as cartilage and ultrasoft elastomers. However, the progress in ...
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Journal articleMacromolecules · 2016
Molecular dynamics simulations of a coarse-grained bead–spring model have been used to study the effects of molecular crowding on the accumulation of tension in the backbone of bottle-brush polymers tethered to a flat substrate. The number of bottle-brushe ...
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Journal articleMacromolecules · 2016
We present a versatile synthetic route leading toward generating surface-attached polyacrylamide gels, in which the cross-link density varies continuously and gradually across the substrate in two orthogonal directions. We employ free radical polymerizatio ...
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Journal articlePolymer (United Kingdom) · 2016
Stable microbubbles can be prepared by evaporation of a liquid core inside an expandable polymeric shell. To control the expansion temperature and the size of resulting microbubbles, we prepared polymeric microcapsules that contain multiple liquids in thei ...
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Journal articleNature Communications · 2016
It is well accepted that adding nanoparticles (NPs) to polymer melts can result in significant property improvements. Here we focus on the causes of mechanical reinforcement and present rheological measurements on favourably interacting mixtures of spheric ...
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Journal articleNature · 2016
Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest1–3. Surface-patterned particles act as colloidal analogues of atoms and molecules4,5 , serve as model systems in ...
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Journal articleMacromolecules · 2016
A scaling model of self-similar conformations and dynamics of nonconcatenated entangled ring polymers is developed. Topological constraints force these ring polymers into compact conformations with fractal dimension df = 3 that we call fractal loopy globul ...
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Journal articleMacromolecules · 2015
The self-assembly of synthetic diblock copolymers has been extensively studied experimentally and theoretically. In contrast, self-assembly of polypeptide diblock copolymers has so far been mostly studied experimentally. We discovered that the theory devel ...
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Journal articleSoft Matter · 2015
Soft materials are abundant in nature and ubiquitous in living systems. Elucidating their multi-faceted properties and underlying mechanisms is not only theoretically challenging and important in its own right, but also serves as the foundation for new mat ...
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Journal articleMacromolecules · 2015
A scaling theory is developed for selective adsorption of polymers induced by the strong binding between specific monomers and complementary surface adsorption sites. By ?selective? we mean specific attraction between a subset of all monomers, called ?stic ...
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Journal articleMacromolecules · 2015
We propose a hopping mechanism for diffusion of large nonsticky nanoparticles subjected to topological constraints in both unentangled and entangled polymer solids (networks and gels) and entangled polymer liquids (melts and solutions). Probe particles wit ...
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Journal articleACS Macro Letters · 2015
Large-scale simulations of the swelling of a long N-mer in a melt of chemically identical P-mers are used to investigate a discrepancy between theory and experiments. Classical theory predicts an increase of probe chain size R ∼ P-0.18 with decreasing degr ...
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Journal articleComposites Science and Technology · 2015
Two all-aromatic, high-performance poly(etherimide)s ODPA-P3 (I) and BPDA-P3 (II) are studied as a function of SWCNT loading. Polyetherimide I is amorphous but SWCNTs nucleate crystallization during imidization to produce a nanocomposite (nc-I) with SWCNTs ...
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Journal articleNature Materials · 2015
The fabrication of multifunctional materials with tunable structure and properties requires programmed binding of their building blocks. For example, particles organized in long-ranged structures by external fields can be bound permanently into stiff chain ...
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Journal articleAdvanced Materials · 2015
Soft, solvent-free poly(dimethylsiloxane) elastomers are fabricated by a one-step process via crosslinking bottlebrush polymers. The bottlebrush architecture prevents the formation of entanglements, resulting in elastomers with precisely controllable low m ...
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Journal articleScientific Reports · 2015
Flow of soft matter objects through one-dimensional environments is important in industrial, biological and biomedical systems. Establishing the underlying principles of the behavior of soft matter in confinement can shed light on its performance in many m ...
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Journal articleAmerican Journal of Respiratory and Critical Care Medicine · 2015
RATIONALE: Chronic bronchitis (CB) is characterized by persistent cough and sputum production. Studies were performed to test whether mucus hyperconcentration and increased partial osmotic pressure, in part due to abnormal purine nucleotide regulation of i ...
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Journal articlePolymer (United Kingdom) · 2014
In this study we contrast the behavior of an amorphous polyetherimide (ODPA-P3) with that of a semi-crystalline one (BPDA-P3) on introducing single-wall carbon nanotubes (SWCNTs; 0.1-4.4 vol.%). The SWCNTs act as a nucleating agent and induce crystallinity ...
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Journal articleMacromolecules · 2014
\textlessp\textgreaterLarge-scale molecular dynamics simulations are used to study the internal relaxations of chains in nanoparticle (NP)/polymer composites.\textless/p\textgreater ...
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Journal articlePolymer (United Kingdom) · 2014
Reversible-addition fragmentation chain transfer (RAFT) polymerization enabled the synthesis of novel, stimuli-responsive, AB and ABA block copolymers. The B block contained oligo(ethylene glycol) methyl ether methacrylate (OEG) and was permanently hydroph ...
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Journal articleAngewandte Chemie - International Edition · 2014
The resemblance between colloidal and molecular polymerization reactions is very useful in fundamental studies of polymerization reactions, as well as in the development of new nanoscale systems with desired properties. Future applications of colloidal pol ...
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Journal articleMacromolecules · 2014
We develop a scaling model relating the friction forces between two polyelectrolyte brushes sliding over each other to the separation between grafted surfaces, number of monomers and charges per chain, grafting density of chains, and solvent quality. We de ...
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Journal articleLangmuir · 2013
We introduce a facile approach for the production of gas-filled microcapsules designed to withstand high pressures. We exploit microfluidics to fabricate water-filled microcapsules that are then externally triggered to become gas-filled, thus making them m ...
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Journal articleMacromolecules · 2013
We have selected two amorphous all-arom. poly(ether imide)s with similar chem. structures but with different backbone geometries as matrixes for SWCNT-based nanocomposites. Up to 4.4 vol. %, SWCNTs could be incorporated using an in situ polymn. method. N ...
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Journal articleCitation: Review of Scientific Instruments The Journal of the Acoustical Society of America REVIEW OF SCIENTIFIC INSTRUMENTS · 2013
Acoustics are commonly used for borehole (i.e., oil well) imaging applications, under conditions where temperature and pressure reach extremes beyond that of conventional medical ultrasonics. Re-cently, there has been an interest in the application of enca ...
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Journal articleMacromolecules · 2013
Self-healing polymeric materials are systems that after damage can revert to their original state with full or partial recovery of mechanical strength. Using scaling theory we study a simple model of autonomic self-healing of unentangled polymer networks. ...
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Journal articleJournal of the American Chemical Society · 2013
Assembly of nanoscale materials from nanoparticle (NP) building blocks relies on our understanding of multiple nanoscale forces acting between NPs. These forces may compete with each other and yield distinct stimuli-responsive self-assembled nanostructures ...
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Journal articleNature Materials · 2013
The difficulty of mixing chemically incompatible substances–in particular macromolecules and colloidal particles–is a canonical problem limiting advances in fields ranging from health care to materials engineering. Although the self-assembly of chemically ...
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Journal articleProceedings of the National Academy of Sciences · 2013
A similarity between chemical reactions and self-assembly of nanoparticles offers a strategy that can enrich both the synthetic chemistry and the nanoscience fields. Synthetic methods should enable quantitative control of the structural characteristics of ...
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Journal articleACS Macro Letters · 2013
We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts ?0,linear to their ring counterparts ?0,ring at ...
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Journal article · August 24, 2012
Mucus clearance is the primary defense mechanism that protects airways from inhaled infectious and toxic agents. In the current gel-on-liquid mucus clearance model, a mucus gel is propelled on top of a " watery " periciliary layer surrounding the cilia. Ho ...
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Journal articleSoft Matter · 2012
Many important biological macromole-cules, such as DNA, RNA, polypeptides, and polysaccharides, as well as large number of artificial macromolecules, such as poly(styrene sulfonate) (PSS) and pol-yacrylic acid (PAA), are highly charged polyelectrolytes. Co ...
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Journal articleSoft Matter · 2012
Intramolecular repulsion between charged monomers imposes intrinsic tension in polyion, modifies its elasticity, and changes the dependence of polyelectrolyte brush thickness on salt concentration. We demonstrate that intrinsic polyion tension gives rise t ...
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Journal articleMacromolecules · 2011
The paper presents scaling analysis of mechanical tension generated in densely branched macromolecules tethered to a solid substrate with a short linker. Steric repulsion between branches results in z-fold amplification of tension in the linker, where z is ...
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Journal articleMacromolecules · 2011
We use scaling theory to derive the time dependence of the mean-square displacement 〈Δr(2)〉 of a spherical probe particle of size d experiencing thermal motion in polymer solutions and melts. Particles with size smaller than solution correlation length ξ u ...
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Journal articleBiophysj · 2011
Hepatitis C virus NS3 helicase couples ATP binding and hydrolysis to polynu-cleotide unwinding. Understanding its regulation mechanism of ATP binding will facilitate targeting of ATP binding site for potential hepatitis C treatment. T324, a residue connect ...
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Journal articlePolymers for Advanced Technologies · 2011
The ability to form blends of polymers offers the opportunity of creating a new class of materials with enhanced properties. In addition to the polymer components, recent advances in nanoengineering have resulted in the development of nanosized inorganic p ...
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Journal article · July 9, 2010
Self-organization of nanoparticles is an efficient strategy for producing nanostructures with complex, hierarchical architectures. The past decade has witnessed great progress in nanoparticle self-assembly, yet the quantitative prediction of the architectu ...
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Journal articleJournal of the American Chemical Society · 2010
Mechanical activation of chemical bonds typically involves the application of external forces, which implies a broad distribution of bond tensions. We demonstrate that controlling the flow profile of a macromolecular fluid generates and delineates mechanic ...
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Journal articleMacromolecules · 2010
The mechanical response of networks, gels, and brush layers is a manifestation of the elastic properties of the individual macromolecules. Furthermore, the elastic response of macromolecules to an applied force is the foundation of the single-molecule forc ...
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Journal articleMethods · 2010
We report a fully general technique addressing a long standing challenge of calculating conformational free energy differences between various states of a polymer chain from simulations using explicit solvent force fields. The main feature of our method is ...
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Journal articleJournal of Physical Chemistry B · 2009
Molecular bottle-brushes are highly branched macromolecules with side chains densely grafted to a long polymer backbone. The brush-like architecture allows focusing of the side-chain tension to the backbone and its amplification from the pico-Newton to nan ...
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Journal articleMacromolecules · 2009
Spurred by an experimental controversy in the literature, we investigate the end-monomer dynamics of semiflexible polymers through Brownian hydrodynamic simulations and dynamic mean-field theory. Precise experimental observations over the last few years of ...
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Journal articlePhysical Review Letters · 2009
We propose a method for the design of branched macromolecules that are capable of building up high tension ( approximately nN) in their covalent bonds without applying an external force. The tension is self-generated due to repulsion between branches and d ...
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Journal articleMacromolecules · 2008
Abstract: We present a scaling theory for solutions of star-branched polyelectrolytes in different concentration regimes. We distinguish between two cases of counterion distribution around the star arms and describe differences in the structure of stars wi ...
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Journal articleMacromolecules · 2008
While the effect of the insoluble block length on micelle properties is well understood, the effect of the soluble block is still controversial. We, therefore, have investigated the effect of the molecular weight of the soluble block on the critical micell ...
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Journal articleNature Materials · 2008
After many years of intense research, most aspects of the motion of entangled polymers have been understood. Long linear and branched polymers have a characteristic entanglement plateau and their stress relaxes by chain reptation or branch retraction, resp ...
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Journal articlePhysical Review Letters · 2008
We discovered pH-induced selective desorption and readsorption of weakly acidic polymers from polyacid or polybase layer-by-layer films. In situ attenuated total reflection Fourier transform infrared spectroscopy confirms the selectivity of polyacid releas ...
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Journal articleMacromolecules · 2008
The analysis of intrachain monomeric interactions reveals a new effect in the description of polymer conformations in dilute theta-solutions, semidilute solutions, and melts. The chain connectivity modifies the effective monomeric interaction, which result ...
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Journal articleJournal of the American Chemical Society · 2008
We report a predefined self-organization of gold nanorods (NRs) end-terminated with multiple polymer arms ("pom-poms") in higher-order structures. The assembly of polymer-tethered NRs was controlled by changing the structure of the polymer pom-poms. We sho ...
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Journal articlePhysical Review Letters · 2007
The generalization of the Flory theorem for structurally asym. mixts. was derived and tested by direct visualization of conformational transformations of brushlike macromols. embedded in a melt of linear chains. Swelling of a brush mol. was shown to be con ...
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Journal articleNature Materials · 2007
Organized arrays of anisotropic nanoparticles show electronic and optical properties that originate from the coupling of shape-dependent properties of the individual nanorods. The organization of nanorods in a controllable and predictable way provides a ro ...
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Journal articleMacromolecules · 2007
We performed molecular dynamics simulations of dilute and semidilute polyelectrolyte solutions without hydrodynamic interactions to study Rouse dynamics of polyelectrolytes. Polyelectrolyte solutions are modeled by an ensemble of bead-spring chains of char ...
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Journal articleAdvanced Materials · 2007
Monitoring of brush-like macromolecules as they change their shape in response to variations in the film pressure during flow were reported. After appropriate calibration, these molecular sensors can be used to gauge both the pressure gradient and the fric ...
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Journal articleProceedings of the National Academy of Sciences · November 28, 2006
A vexing problem in cystic fibrosis (CF) pathogenesis has been to explain the high prevalence of Pseudomonas aeruginosa biofilms in CF airways. We speculated that airway surface liquid (ASL) hyperabsorption generates a concentrated airway mucus that intera ...
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Journal articleLangmuir · 2006
Long-range orientational order in monolayers of brush-like macromolecules was achieved during spreading of a polymer melt on the surface of highly oriented pyrolytic graphite. The combination of wetting-induced flow and epitaxial adsorption of poly(n-butyl ...
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Journal articleMacromolecules · 2006
Reversible morphological transitions of diblock copolymer micelles in dilute solutions were monitored by light scattering and atomic force microscopy for two different polymer samples near the calculated morphological boundaries. These transitions were ind ...
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Journal articleMacromolecules · 2006
We have developed a necklace model of hydrophobic polyelectrolytes in which the necklace structure consisting of polymeric globules (beads) connected by extended sections of the chain (strings of monomers) appears as a result of the counterion condensation ...
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Journal articleMacromolecules · 2006
The conformational properties of symmetric flexible diblock polyampholytes are investigated by scaling theory and molecular dynamics simulations. The electrostatically driven coil-globule transition of a symmetric diblock polyampholyte is found to consist ...
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Journal articleNature · 2006
Covalent carbon–carbon bonds are hard to break. Their strength is evident in the hardness of diamonds1,2 and tensile strength of polymeric fibres3–6; on the single-molecule level, it manifests itself in the need for forces of several nanonewtons to extend ...
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Journal articleMacromolecules · 2006
The solution properties of a fluorinated alkyl methacrylate, poly(1,1,2,2-tetrahydroperfluorooctyl methacrylate) (PFOMA), in liquid and supercritical carbon dioxide (CO2) were studied by static and dynamic light scattering. The solvent quality of CO2 was f ...
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Journal articleProgress in Polymer Science (Oxford) · 2005
Polyelectrolytes are polymers carrying either positively or negatively charged ionizable groups. The properties of these polymers in solutions and at charged surfaces depend on the fraction of dissociated ionic groups, solvent quality for polymer backbone, ...
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Journal articlePhysical Review Letters · 2005
A new type of flow fingering instability was obsd. in monolayer-thick acrylic graft polymer films as they spread on a solid substrate. Tracing the movement of individual mols. by at. force microscopy enabled us to follow the development of the flow instabi ...
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Journal articleMacromolecules · 2005
We performed theor. and exptl. investigations of dil. solns. of micelles of neutral amorphous diblock copolymers in selective solvents. The ranges of thermodn. stability of spherical, cylindrical, and lamellar morphologies along with the equil. sizes and a ...
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Journal articleMacromolecules · 2005
We have developed a scaling theory for a salt-free solution of diblock polyampholytes. A charge-symmetric diblock polyampholyte chain with equally charged positive and negative blocks collapses into a globule. This collapse is driven by the electrostatic a ...
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Journal articleMacromolecules · 2005
The unexpected scaling dependence R-n similar to n(0.72) of the size Rn of the chain section with n monomers observed in recent numerical simulations of a swollen network and globule is explained on the basis of the slip-tube model. We demonstrate that the ...
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Journal articleMacromolecules · 2004
Wormlike micelles can form from polystyrene-b-polyisoprene copolymers in heptane as selective solvent for polyisoprene. We have measured the aggregation number per unit length of polystyrene-b-polyisoprene wormlike micelles by light scattering and AFM. The ...
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Journal articleJournal of Polymer Science, Part B: Polymer Physics · 2004
: Polyampholytes are charged polymers with both positively and negatively charged groups. The conformation of these polymers in solutions strongly depends on the distribution of charged monomers along the polymer backbone and their environ- ment. In this r ...
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Journal articlePhysical Review Letters · 2004
Spreading of a polymer drop on a solid substrate was monitored with mol. resoln. Three characteristic rates, i.e., the spreading rate of the precursor film Dspread=(3.9±0.2)×103 nm2/s, the flow-induced diffusion rate of mols. within the film Dinduced=1.3±0 ...
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Journal articleJournal of Physical Chemistry A · 2004
In this paper, we report the results of static and dynamic light scattering investigations of polydimethyl siloxane (PDMS) solutions in both liquid and supercritical carbon dioxide (CO2). This study was performed below the theta point and provides quantita ...
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Journal articleThe Journal of Chemical Physics Journal of Chemical Physics The Journal of Chemical Physics II The Journal of Chemical Physics The Journal of Chemical Physics The Journal of Chemical Physics Journal of Chemical Physics · 2003
The second virial coefficient, A 2 , is evaluated between pairs of short chain molecules by direct simulations using a parallel tempering Monte Carlo method where the centers of mass of the two molecules are coupled by a harmonic spring. Three off-lattice ...
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Journal articleMacromolecules · 2003
Osmotic coefficients and counterion distribution functions of rodlike and flexible polyelectrolyte chains have been studied using molecular dynamics simulations of multichain systems with explicit counterions in salt-free solutions. Using the counterion de ...
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Journal articleMacromolecules · 2003
We present the results of molecular dynamics simulations of polyelectrolyte solutions in near-?-solvent conditions for polymer backbone. Polyelectrolyte solutions are modeled as an ensemble of bead-spring chains of charged Lennard-Jones particles with expl ...
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Journal articleJournal of Rheology · 2003
... At low shear rates the stress increases linearly with shear rate, at intermediate rates there is a ... This holds until where at these very high rates the assumption that the chains are at ... by linear oscillatory shear measurements or were set to uni ...
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Journal articleMacromolecules · 2002
We develop a scaling theory of adsorption of necklace-like hydrophobic polyelectrolytes at an oppositely charged hydrophilic and hydrophobic surfaces. At low surface charge densities we predict a two-dimensional adsorbed layer with thickness determined by ...
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Journal articleMacromolecules · 2002
We develop a theory for the dynamics in entangled solutions of associating polymers with many stickers per chain. The stickers strongly associate and form large aggregates that control both the equilibrium structure of the system and its dynamics. The asso ...
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Journal articleMacromolecules · 2002
We develop and solve a new molecular model for nonlinear elasticity of entangled polymer networks. This model combines and generalizes several succeseful ideas introduced over the years in the field of the rubber elasticity. The topological constraints imp ...
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Journal articleJournal of the American Chemical Society · 2002
Polymeric nanogel vectors were developed for cellular gene and antisense delivery. Inverse microemulsion polymerization was utilized to synthesize biocompatible nanogels with controlled size, morphology, and composition. The chemical composition, size, pol ...
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Journal articleMacromolecules · 2001
We have developed a theory of adsorption of polyampholyte chains at a charged planar surface and a charged spherical particle from dilute low salt solutions. The adsorption is due to the polarization of polyampholyte chains in the external electric field c ...
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Journal articleMacromolecules · 2001
The process of making and breaking reversible bonds between associating groups (stickers) controls the dynamics of associating polymers. We develop a theory of “sticky reptation” to model the dynamics of entangled solutions of associating polymers with man ...
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Journal articleJournal of Physical Chemistry B · 2001
We develop a scaling theory of adsorption of polyampholyte chains at charged spherical particles from dilute low salt solutions. The adsorption is due to the polarization of polyampholyte chains in the electric field created by charged particles. The expre ...
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Journal articleMacromolecules · 2001
We have developed a scaling theory of polyelectrolyte adsorption at an oppositely charged surface. At low surface charge densities, we predict two-dimensional adsorbed layers with thickness determined by the balance between electrostatic attraction to the ...
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Journal articleEuropean Physical Journal E · 2001
We develop a scaling theory for a single polyampholyte chain adsorbed$$non a charged spherical particle in a theta-solvent. Adsorption of$$na polyampholyte molecule is doe to its polarization in the electrostatic$$nfield of the particle. For large particle ...
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Journal articlePhysical Review Letters · 2001
In dilute solutions of rodlike polyelectrolytes some counterions are distributed far from polyions while others are located in their vicinity in the regions of cylindrical symmetry of the electrostatic potential. For these cylindrical regions around rodlik ...
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Journal articleMacromolecules · 2001
We have developed a theory of counterion condensation in solutions of hydrophobic polyelectrolytes. In the framework of Oosawa’s two-zone model we demonstrate that solutions of necklaces can be unstable with respect to phase separation. This phase separati ...
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Journal articlePhysical Review Letters · 2000
We introduce a lattice model of glass transition in polymer globules. This model exhibits ergodicity breaking in which the disjoint regions of phase space do not arise uniformly, but as small chambers whose number increases exponentially with polymer densi ...
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Journal article · 2000
We develop a scaling theory of polyelectrolyte adsorption at an oppositely charged surface. At low surface charge densities, the thickness of the adsorbed layer is determined by the balance between electrostatic attraction to the charged surface and chain ...
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Journal articleMacromolecules · 2000
The universal diagram of states of hydrophobically modified polyelectrolytes in dilute salt-free solutions is calculated in the framework of the scaling approach. The equilibrium conformations of these polymers were classified using two parameters geometri ...
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Journal articleJournal of Rheology · 2000
We present a comparison of various rheological models based on the double reptation concept, which relates linear viscoelastic data to molecular-weight distribution in order to determine the most efficient way to describe polydispersity effects. We have us ...
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Journal articleMacromolecules · 1999
We develop a theory of the adsorption of many polyampholyte chains on a charged surface. The adsorption is due to the polarization of polyampholyte chains in the external electric field created by the charged surface. The equilibrium polymer density profil ...
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Journal articleMacromolecules · 1999
We present a scaling model of hydrophobic polyelectrolytes. In dilute salt-free solutions these polymers have a necklacelike shape with compact beads joined by narrow strings. This necklacelike structure manifests itself in the unique scaling laws in semid ...
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Journal articleJournal of Chemical Physics · 1998
We consider the motion and the deformation of Gaussian polyampholytes in free flow electrophoresis, i.e., in an applied external electric field. The electrophoretic mobility and the deformation of the chains are calculated in the linear regime, as function ...
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Journal articleMacromolecules · 1998
An equilibrium mean?field theory for reversible network formation in solutions of associative polymers is presented. We study polymer solutions with many associating groups per chain and consider pairwise association of these groups. A simple analytical ex ...
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Journal articleMacromolecules · 1998
Viscoelastic properties of reversible networks formed in solutions of associating polymers are considered theoretically in the Rouse?Zimm (unentangled) regime. It is shown that the dynamics is governed primarily by the network strand size and by the effect ...
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Journal articleEuropean Physical Journal B · 1998
The effect of excluded-volume interactions on the reptation dynamics of long polymer chains is considered theoretically. It is shown that interactions give rise to an exponential increase of the reptation time, tau(rep) similar to exp[(n/n*)(2/3)], if poly ...
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Journal articleThe Journal of Chemical Physics The Journal of Chemical Physics The Journal of Chemical Physics The Journal of Chemical Physics Journal of Chemical Physics Colligative Properties The Journal of Chemical Physics The Journal of Chemical Physics · 1998
We calculate the interaction between two identically charged surfaces immersed in a polyampholyte solution in the framework of the linear response approximation. In the case of the randomly charged polyampholyte with equal fractions of positively f ϩ and n ...
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Journal articleMacromolecules · June 2, 1997
Complex formation between negatively charged polyelectrolytes and a net negatively charged polyampholyte (gelatin) has been characterized by light scattering. The two polyanions studied are sodium poly(styrenesulfonate) (NaPSS) and sodium poly(2-acrylamido ...
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Journal articleJournal de Physique I · 1997
We present a simple minimal model which allows numerical and analytical study of a glass transition. This is a model of rigid rods with fixed centers of rotation. The rods can rotate freely but cannot cross each other. The ratio l of the length of the rods ...
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Journal articleNature · 1997
Dendrimers are well defined, highly branched polymers(1-5) that adopt a roughly spherical, globular shape in solution, Their cores are relatively loosely packed and can trap guest molecules(5-7), and by appropriate functionalization of the branch tips the ...
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Journal articlePhysical Review Letters · 1997
We have measured the diffusion of deuterated polystyrene of molecular weight 90 x 10(3) in various matrices of hydrogenated polystyrene as a function of distance from an attractive interface, oxide-covered silicon. Surprisingly long-range effects are obser ...
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Journal articleMacromolecules · August 4, 1996
We develop a scaling model for the dilute solution conformation of a uniformly charged polymer in a poor solvent. We find that there is a range of temperatures and charge densities for which the polymer has a necklace-like shape with compact beads joined b ...
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Journal articleElectrophoresis · 1996
We present a new model for the motion of a megabase-long DNA molecule undergoing gel electrophoresis. We assume that the dynamics of large seg-ments of DNA is almost deterministic and can be described by a set of simple mechanical equations. This allows th ...
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Journal articleMacromolecules · 1996
Polymer blends, mixtures, or block copolymers can be cross-linked in a homogeneous state forming a multicomponent network. Upon cooling such network, the repulsion between different components may lead to a microphase separation into regions rich in each o ...
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Journal articleMacromolecules · 1996
We present a scaling theory for the modulus G of polyelectrolyte gels as a function of strand length between cross-links, monomer concentration c, salt concentration cs, and preparation conditions (monomer concentration c0 and salt concentration cs°). The ...
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Journal articleMacromolecules · 1996
We examine the equilibrium properties of a starburst dendrimer. A simple Flory theory is developed for the dependence of the radius of gyration of the starburst on its generation. A self-consistent mean field model is solved numerically to verify the Flory ...
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Journal articleMacromolecules · 1995
We extend and generalize the scaling picture of de Gennes et al. and Pfeuty to both unentangled and entangled regimes of intrinsically flexible polyelectrolyte solutions. In semidilute solution the electrostatic persistence length of a polyelectrolyte is a ...
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Journal articlePhysical Review Letters · 1995
The tracer diffusion coefficients D* of polystyrene (PS) chains near PS melt-solid interfaces have been measured by secondary ion mass spectrometry. The D* for poly(2-vinylpyridine) (PVP) and oxide (SiO) covered silicon surfaces were smaller by, respective ...
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Journal articleMacromolecules · 1994
We discuss the elastic modulus G and swelling/deswelling behavior of networks as a function of their concentration Ï and their preparation state. Simple scaling ideas reproduce the prediction of James and Guth for the modulus of networks swollen in a θ s ...
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Journal articleMacromolecules · 1994
We derive the mobility and the relaxation time of stars (with g arms of Z monomers each) or long linear Z-mers embedded in a homopolymer melt of linear chains of N monomers, using a dissipation approach recently proposed by de Gennes.20 For stars, we expec ...
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Journal articleMacromolecules · 1994
Scaling ideas are used to predict the modulus G0 of gels, just above the point of incipient gel formation, in the reaction bath as a function of the proximity to the gel point e. The concentration dependence of the modulus when the gel is diluted in a good ...
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Journal articlePhysica A: Statistical Mechanics and its Applications · 1994
We analyse the way grafted polymers modify the slippage of an entangled polymer melt on an ideal surface. We take into account the deformation of the grafted chains in the flow (non-linear effects) and show that it alters significantly their efficiency as ...
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Journal articleMacromolecules · 1994
We study theoretically the hexagonal phase of diblock copolymer melts and determine the conditions under which a region of lamellar ordering is induced near a flat surface. In the weak segregation limit we employ a Landau-Ginzburg mean-field theory to desc ...
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Journal articleJournal de Physique II, EDP Sciences · 1994
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Journal articlePhysical Review Letters · 1994
We present a simple scaling theory of the dynamics of a ring polymer in a gel. In the absence of excluded volume interactions, we predict that the translational diffusion coefficient D varies with the molecular weight M as D approximately M-2 and the longe ...
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Journal articlePhysical Review Letters · 1994
We apply dynamic scaling to both unentangled and entangled semidilute polyelectrolyte solutions. The unentangled semidilute regime can span three to four decades of polymer concentration in low-salt solutions. In this range we predict such phenomena as a c ...
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Journal articlePhysical Review E · January 11, 1993
We report the viscosity and the modulus of near-critical polyester gels. Previous work has shown that these gels lie in the middle of the static crossover between mean-field and critical percolation. Above the gel point, the modulus data are well described ...
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Journal articleJ. Phyi. /I h-ancr · 1993
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Journal article · 1993
A chain reptating through a high molecular weight polymer melt leaves a trace in the form of elastic distortions of an entanglement network. Neighboring chains can partially relax these elastic distortions by following this trace with some accuracy. Thus t ...
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Journal articleJournal de Physique II EDP Sciences · 1993
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou p ...
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Journal articleMacromolecules · 1993
We consider stress relaxation in a strongly segregated lamellar mesophase, where block copolymers are in the " brush " state with junction points confined to the interface between the adjacent lamellae and blocks stretched out away from it. If the molecula ...
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Journal articleJournal de Physique II, EDP Sciences · 1993
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou p ...
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Journal articlePhysical Review Letters · 1992
A tetrafunctional network of freely jointed rigid rods in 2 dimensions is studied. At equil., the network is in a highly swollen state. Surprisingly, such a network is a crit. object with large crosslink d. fluctuations on all length scales and anomalously ...
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Journal articleMacromolecules · 1992
We report experimental data on gel fraction, gel equilibrium swelling, sol intrinsic viscosity, and molecular weight distribution of the sol for a series of polyester samples above the gel point. The data are analyzed in terms of scaling relations suggeste ...
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Journal articleMacromolecules · 1992
Poly(3,5-dihydroxybenzyl alc.) dendrimers made by the convergent growth approach are characterized by size exclusion chromatog. (SEC) with coupled mol.-wt.-sensitive detection. SEC chromatograms are as narrow as chromatograms of polystyrene with mol.-wt. d ...
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Journal articleMacromolecules · 1992
We consider the problem of entanglement in polymer melts and solutions with no excluded-volume interactions (esolvent). A number of simple ideas on this subject, cast in the form of scaling theories, have recently been proposedintheliterature. Atfirstglanc ...
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Journal articleMakromolekulare Chemie. Macromolecular Symposia · 1992
Localization of cross-links is an important issue in the theory of rubber elasticity. We consider freely-hinged rigid rod networks and show that in some cases they behave like critical objects: junctions fluctuate on all length scales. Such networks exhibi ...
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Journal articleMacromolecules · 1991
We consider the concepts of reptation and constraint release to model the dynamics of poly-disperse linear polymers. The mechanisms of constraint release at work in concentrated polymer solutions can be divided into two categories. Tube dilation occurs whe ...
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Journal articleMacromolecules · 1991
We present a model for dynamics of entangled networks made up of linear chains with many temporary cross-links. At times shorter than the lifetime of a cross-link such networks behave as elastic rubbers (gels). On longer time scales the successive breaking ...
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Journal articlePhysical Review Letters · September 3, 1990
We predict a glass transition in the recently discovered flux-fiuid state of high-T, superconductors due to topological entanglements. Two possible relaxation mechanisms are considered — single-flux-line motion with relaxation time t -exp[exp[(A/d) ][, an ...
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Journal articleMacromolecules · 1990
We revive an old conjecture that a fixed number of binary contacts between chains collec-tively make up the topological constraint commonly referred to as an entanglement. This leads us to a general scaling theory for semidilute polymer solutions which inv ...
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Journal articlePhysical Review A · 1989
A new kinetic real-space renormalization-group (KRG) approach to diffusion-limited aggregation (DLA) is presented. It is based on the combined length- and time-scale invariance of the clusters. The probabilities relating different local configurations unde ...
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Journal articlePhysics Letters A · 1989
A new kinetic real-space renormalization group approach to the diffusion-limited aggregates is presented. The fractal dimension (Df) and the set of hierarchical dimensions D(q) are computed for the DLA cluster on the square lattice. We find Df=Ds=1.727 (Ds ...
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Journal articleJournal of Physics A: General Physics · 1989
An improved kinetic renormalisation group approach to diffusion-limited aggregation is presented. This approach is based on the growth process itself and accounts for the dispersity in the growth probabilities. It yields the multifractal spectrum D(q) with ...
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Journal articleThe Journal of Chemical Physics · October 15, 1988
The effects of polydispersity on the linear viscoelastic properties of concentrated polymer solutions and melts are analyzed. Existing theories for the dynamics of linear polymers, based on the idea of each polymer confined in a fixed tube, are sho ...
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Journal articleMacromolecules · 1987
Effects of polydispersity on rheological properties of entangled polymers are analyzed. A number of models of tube renewal are discussed and compared with each other and with experiments. A theory incorporating reptation, tube renewal, and fluctuations in ...
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Journal articlePhysical Review Letters · 1987
A discretized version of the reptation model is proposed. The tube is modeled by a one-dimensional lattice and the polymer is modeled by a cluster of walkers, called reptons, on this lattice. Each repton represents a part of the chain. Reptons are allowed ...
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Journal articlePhysical Review Letters · 1986
The configurations and dynamics of a polymer ring (R) inside a strongly crosslinked polymer gel (G) are discussed and compared to those of linear (L) and branched (B) polymers in G. R is not topologically connected to G in the sense that the contour line o ...
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Journal articlePhysical review B: Condensed matter and materials physics · May 15, 1983
The resistance of a one-dimensional periodic potential with large unit cell is analyzed as a function of Fermi energy and potential strength. We demonstrate that even in the allowed en-ergy regions the resistance can be nonzero due to the boundary contribu ...
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Journal articlePhysical Review Letters · 1983
The correlation function of the phases of a quantum particle in a one-dimensional random potential is defined and calculated analytically and numerically. Away from eigen-states it decays exponentially with the phase correlation length equal to half of the ...
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Journal articlePhilosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties · 1982
ISSN: 0141-8610 (Print) 1460-6992 (Online) Journal homepage: http://www.tandfonline.com/loi/tpha20 ABSTRACT Translational and orientational order in randomly packed planar arrays of hard spheres of two different sizes is investigated. For an appropriate si ...
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Journal article
Large-scale molecular dynamics simulations are used to study the internal relaxations of chains in nanoparticle (NP)/polymer composites. We examine the Rouse modes of the chains, a quantity that is closest in spirit to the self-intermediate scattering func ...
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Journal article
We have studied the effect of short-range interactions on polyelectrolyte adsorption at oppositely and similarly charged surfaces. The properties of the adsorbed layer, such as polymer surface coverage, layer thickness, and surface overcharging (for adsorp ...
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Journal article
The behavior of polymeric surfactant polyvinyl acetate (PVAC)-b-poly(1,1,2,2-tetrahydro-perfluorooctyl acrylate) (PTAN) in supercritical carbon dioxide (CO2) was investigated using static and dynamic light scattering. We observed three regions on the phase ...
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Journal article
We demonstrate that the origin of the nonlinear elasticity of polymer networks rests in their nonaffine deformations. We introduce the affine length Raff, which separates the solid-like elastic deformations on larger scales from liquid-like nonaffine defor ...
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