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

Journal Article · Tue Nov 01 00:00:00 EST 2005 · Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics

DOI:https://doi.org/10.1103/PhysRevE.72.051801· OSTI ID:20709833

Yim, H; Kent, M S; Satija, S; Mendez, S; Balamurugan, S S; Balamurugan, S; Lopez, G P ^[1]

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1. Sandia National Laboratories, Department 8332, Albuquerque, New Mexico 87185 (United States)

The detailed conformational change of poly(N-isopropylacrylamide) (PNIPAM) brushes at high grafting density in D{sub 2}O 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.

• OSTI ID: 20709833
• Journal Information: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Vol. 72, Issue 5; Other Information: DOI: 10.1103/PhysRevE.72.051801; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-651X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMS
CHAINS
CONFORMATIONAL CHANGES
DENSITY
GOLD
HEAVY WATER
LAYERS
MOLECULAR WEIGHT
NEUTRONS
POLYMERIZATION
POLYMERS
RADICALS
REFLECTION
SILICON OXIDES
SURFACES
TEMPERATURE DEPENDENCE