Nonergodic dynamics of a novel thermally sensitive hybrid gel

Citation
Y. Zhao et al., Nonergodic dynamics of a novel thermally sensitive hybrid gel, MACROMOLEC, 34(22), 2001, pp. 7804-7808
Citations number
27
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
MACROMOLECULES
ISSN journal
00249297 → ACNP
Volume
34
Issue
22
Year of publication
2001
Pages
7804 - 7808
Database
ISI
SICI code
0024-9297(20011023)34:22<7804:NDOANT>2.0.ZU;2-M
Abstract
As the temperature decreases, the swelling of individual thermally sensitiv e spherical poly(N-isopropylacrylamide) microgels in a concentrated dispers ion can lead to a sol-gel transition, resulting in a hybrid bulk gel in whi ch individual microgels were physically jam-packed into a three-dimensional network without involving electrostatic interaction, resembling the glass transition of small molecules. The dynamics of such a formed hybrid gel wer e studied by static and dynamic laser light scattering. Our results showed that the inhomogeneity should be characterized by the difference between th e ensemble average scattering intensity and the dynamic component of the ti me average scattering intensity. The inhomogeneity was strongly dependent o n the sol-gel transition rate and the gelling temperature. Our results have also revealed that the inhomogeneity can be completely suppressed if indiv idual swollen microgels are closely packed together, indicating that the st atic nonergodic behavior originates from large voids formed during the sol- gel transition.