Evidence for vertical phase separation in densely grafted, high-molecular-weight poly(N-isopropylacrylamide) brushes in water

The detailed conformational change of poly(N-isopropylacrylamide) (PNIPAM) brushes at high grafting density in D2O was investigated as a function of temperature using neutron reflection. PNIPAM chains were grafted at high surface density from gold and silicon oxide surfaces by atom transfer radical polymerization. Whereas single layer profiles were observed for temperatures below and above the transition region, bilayer profiles were observed for a narrow range of temperatures near the transition. This nonmonotonic change in the concentration profile with temperature is discussed in the context of theoretical models of vertical phase separation within a brush. © 2005 The American Physical Society.

Full Text

Duke Authors

Cited Authors

  • Yim, H; Kent, MS; Satija, S; Mendez, S; Balamurugan, SS; Balamurugan, S; Lopez, GP

Published Date

  • 2005

Published In

Volume / Issue

  • 72 / 5

International Standard Serial Number (ISSN)

  • 1539-3755

Digital Object Identifier (DOI)

  • 10.1103/PhysRevE.72.051801