TY  - JOUR
AU  - Maccarrone, Simona
AU  - Scherzinger, Christine
AU  - Holderer, Olaf
AU  - Lindner, Peter
AU  - Sharp, Melissa
AU  - Richtering, Walter
AU  - Richter, Dieter
TI  - Cononsolvency Effects on the Structure and Dynamics of Microgels
JO  - Macromolecules
VL  - 47
IS  - 17
SN  - 1520-5835
CY  - Washington, DC
PB  - Soc.
M1  - FZJ-2014-05702
SP  - 5982 - 5988
PY  - 2014
AB  - Sensitive microgels are submicrometer sized, cross-linked polymer particles with a unique swelling behavior changing in response to surrounding conditions like temperature, pH and ionic strength. In this study we influence the swelling capability of thermosensitive microgels microgel by the composition of the solvent (cononsolvency). In particular, we investigate the effects on the structure and dynamics of poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-diethylacrylamide) (PDEAAM) microgels with different degree of swelling in MeOD/D2O solvent mixture at 10 °C using a combination of small angle neutron scattering (SANS) and neutron spin echo (NSE) spectroscopy at nanoseconds scales in the range of several nanometers. The structural characterization including size and density profiles was determined by fitting SANS data. The dynamical behavior of partially collapsed and swollen microgels is comprehensively described within the theory of semidilute polymers in solutions where hydrodynamic interactions are dominant. The partially collapsed PNIPAM microgel particles are not solid diffusing objects but they have relevant contributions from internal motions. Thus, Zimm segmental dynamics can be detected with elevated apparent viscosity. The swollen PDEAAM microgel particles have a faster internal dynamics compared to the partially collapsed PNIPAM. It can also be explained by Zimm-like relaxations with relatively high apparent viscosity and an additional diffusive contribution coming from the cross-linkers.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000341542900013
DO  - DOI:10.1021/ma500954t
UR  - https://juser.fz-juelich.de/record/172213
ER  -