Journal Article

FZJ-2015-03370

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Phase Separation in Semidilute Aqueous Poly( N -isopropylacrylamide) Solutions

Meier-Koll, A. ; Pipich, V.FZJ* ; Busch, P.FZJ* ; Papadakis, C. M. ; Müller-Buschbaum, P. (Corresponding Author)

2012
ACS Publ. Washington, DC

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Please use a persistent id in citations: doi:10.1021/la3015332

Abstract: The phase separation mechanism in semidilute aqueous poly(N-isopropylacrylamide) (PNIPAM) solutions is investigated with small-angle neutron scattering (SANS). The nature of the phase transition is probed in static SANS measurements and with time-dependent SANS measurements after a temperature jump. The observed critical exponents of the phase transition describing the temperature dependence of the Ornstein–Zernike amplitude and correlation length are smaller than values from mean-field theory. Time-dependent SANS measurements show that the specific surface decreases with increasing time after a temperature jump above the phase transition. Thus, the formation of additional hydrogen bonds in the collapsed state is a kinetic effect: A certain fraction of water remains as bound water in the system. Moreover, H–D exchange reactions observed in PNIPAM have to be taken into account.

Keyword(s): Basic research (1st) ; Others (1st) ; Soft Matter, Macromolecules, Complex fluids, Biophysics (1st) ; Soft Condensed Matter (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)

Research Program(s):

1. 54G - JCNS (POF2-54G24) (POF2-54G24)

Experiment(s):

1. KWS-2: Small angle scattering diffractometer (NL3ao)

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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