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Tuning Cooperative Assembly with Bottlebrush Block Co-polymers for Porous Metal Oxide Films Using Solvent Mixtures.

Publication ,  Journal Article
Xia, X; Bass, G; Becker, ML; Vogt, BD
Published in: Langmuir : the ACS journal of surfaces and colloids
July 2019

Block copolymer templating enables the generation of well-defined pore sizes and geometries in a wide variety of frameworks, typically through evaporation-induced self-assembly (EISA). Here, we systematically modulate the solvent quality with mixtures of tetrahydrofuran-ethanol (THF-EtOH) to manipulate the unimer/micelle ratio in the precursor solution to explore how the associated solution structure influences the final pore morphology. A bottlebrush block copolymer (BBCP) with poly(ethylene oxide) and poly(t-butyl acrylate) side chains was used as the template for pore formation. Irrespective of the solvent composition, a bimodal pore size distribution was obtained with mesopores templated by small aggregates of the BBCP unimers (potentially low aggregation number micelles) and macropores templated by large self-assembled BBCP micelles. The morphology and pore characteristics of the metal oxide films were dependent on the THF-EtOH composition. Interestingly, an intermediate solvent composition where the volume of micelles is approximately half the volume of unimers (in the precursor solution) leads to the best ordering of micelle-templated pores and also the maximum porosity in the films. The micelle/unimer ratios in the precursor solutions do not correspond directly to the bimodal pore distribution in the metal oxide films, which we attribute to kinetically trapped assembly of the BBCP at a low THF content. The increased critical micelle concentration at high THF composition leads to changes in the unimer/micelle ratio during solvent evaporation. These results appear to be universal for a number of metal oxides (cobalt, magnesium, and zinc) with the porosity maximized at a THF/EtOH ratio of 3:1. These results suggest the potential for enhancements in the porosity of block copolymer-templated films by EISA methods through judicious solvent selection.

Duke Scholars

Published In

Langmuir : the ACS journal of surfaces and colloids

DOI

EISSN

1520-5827

ISSN

0743-7463

Publication Date

July 2019

Volume

35

Issue

29

Start / End Page

9572 / 9583

Related Subject Headings

  • Chemical Physics
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Xia, X., Bass, G., Becker, M. L., & Vogt, B. D. (2019). Tuning Cooperative Assembly with Bottlebrush Block Co-polymers for Porous Metal Oxide Films Using Solvent Mixtures. Langmuir : The ACS Journal of Surfaces and Colloids, 35(29), 9572–9583. https://doi.org/10.1021/acs.langmuir.9b01363
Xia, Xuhui, Garrett Bass, Matthew L. Becker, and Bryan D. Vogt. “Tuning Cooperative Assembly with Bottlebrush Block Co-polymers for Porous Metal Oxide Films Using Solvent Mixtures.Langmuir : The ACS Journal of Surfaces and Colloids 35, no. 29 (July 2019): 9572–83. https://doi.org/10.1021/acs.langmuir.9b01363.
Xia X, Bass G, Becker ML, Vogt BD. Tuning Cooperative Assembly with Bottlebrush Block Co-polymers for Porous Metal Oxide Films Using Solvent Mixtures. Langmuir : the ACS journal of surfaces and colloids. 2019 Jul;35(29):9572–83.
Xia, Xuhui, et al. “Tuning Cooperative Assembly with Bottlebrush Block Co-polymers for Porous Metal Oxide Films Using Solvent Mixtures.Langmuir : The ACS Journal of Surfaces and Colloids, vol. 35, no. 29, July 2019, pp. 9572–83. Epmc, doi:10.1021/acs.langmuir.9b01363.
Xia X, Bass G, Becker ML, Vogt BD. Tuning Cooperative Assembly with Bottlebrush Block Co-polymers for Porous Metal Oxide Films Using Solvent Mixtures. Langmuir : the ACS journal of surfaces and colloids. 2019 Jul;35(29):9572–9583.
Journal cover image

Published In

Langmuir : the ACS journal of surfaces and colloids

DOI

EISSN

1520-5827

ISSN

0743-7463

Publication Date

July 2019

Volume

35

Issue

29

Start / End Page

9572 / 9583

Related Subject Headings

  • Chemical Physics