%0 Journal Article
%A Meier-Koll, Andreas
%A Pipich, Vitaliy
%A Busch, Peter
%A Papadakis, Christine M.
%A Müller-Buschbaum, Peter
%T Phase Separation in Semidilute Aqueous Poly( N -isopropylacrylamide) Solutions
%J Langmuir
%V 28
%N 23
%@ 1520-5827
%C Washington, DC
%I ACS Publ.
%M FZJ-2015-03370
%P 8791 - 8798
%D 2012
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000305092700024
%R 10.1021/la3015332
%U https://juser.fz-juelich.de/record/201060