caa a22 4500 378903438 CHVBK 20180305123523.0 cr unu---uuuuu 161128e20041201xx s 000 0 eng 10.1515/epoly.2004.4.1.513 doi (NATIONALLICENCE)gruyter-10.1515/epoly.2004.4.1.513 Small-angle neutron scattering study of shear-induced phase separation in aqueous poly(N-isopropylacrylamide) solutions [Elektronische Daten] [Markus Stieger, Peter Lindner, Walter Richtering] The influence of shear flow on the structure of concentrated aqueous poly(N-isopropylacrylamide) solutions near the lower critical solution temperature was investigated by means of small-angle neutron scattering. Two samples, both in the semi-dilute regime above the overlap concentration, were studied. The scattering curve of the less concentrated sample was not influenced by shear flow, although high shear rates were reached. The more concentrated 4 wt.-% sample, however, displayed shear-induced demixing under strong shear flow conditions. Experiments at different shear stresses indicated the existence of a threshold shear stress and the phase separation process became faster with increasing stress. The two-dimensional scattering patterns remained isotropic even during the phase separation process and the correlation length as obtained from an Ornstein- Zernike plot increased. The influence of shear flow on the phase separation process is thus similar to a temperature increase. The results are in excellent agreement with data from recent rheo-optical experiments where shear-induced phase separation was also observed for the concentrated solution at high shear rates. Apparently, strong shear flow exerts an effect analogous to a temperature increase. © 2013 by Walter de Gruyter GmbH & Co. Stieger Markus Institute of Physical Chemistry, University of Kiel, Olshausenstr. 40, 24098 Kiel, Germany aut Lindner Peter Institute Laue-Langevin, 6 rue Jules Horowitz, BP 156-38042 Grenoble, Cedex 9, France aut Richtering Walter Institute of Physical Chemistry, RWTH Aachen University, Templergraben 59, 52056 Aachen, Germany; Fax +49 241 80 92327 aut e-Polymers De Gruyter 4/1(2004-12-01), 513-522 2197-4586 4:1<513 2004 4 epoly https://doi.org/10.1515/epoly.2004.4.1.513 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/epoly.2004.4.1.513 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Stieger Markus Institute of Physical Chemistry, University of Kiel, Olshausenstr. 40, 24098 Kiel, Germany aut NATIONALLICENCE 700 1- Lindner Peter Institute Laue-Langevin, 6 rue Jules Horowitz, BP 156-38042 Grenoble, Cedex 9, France aut NATIONALLICENCE 700 1- Richtering Walter Institute of Physical Chemistry, RWTH Aachen University, Templergraben 59, 52056 Aachen, Germany; Fax +49 241 80 92327 aut NATIONALLICENCE 773 0- e-Polymers De Gruyter 4/1(2004-12-01), 513-522 2197-4586 4:1<513 2004 4 epoly CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter