The Effect of Polymer Concentration on the Dynamics of Adsorbed Poly(N-isopropylacrylamide) at Particle Surfaces in Water

J Colloid Interface Sci. 1999 Jun 15;214(2):389-394. doi: 10.1006/jcis.1999.6222.

Abstract

Results are presented of a light scattering study of the dynamics of absorbed poly(N-isopropylacrylamide) (PNIPAM) chains at the surfaces of poly(N-tert-butylacrylamide) (PNTBA) latex particles using several different feed weight ratios of PNIPAM to latex particles. The adsorbed layer dynamics under the present experimental conditions were postulated to include both the extended-to-loopily adsorbed state transition of tightly adsorbed chains and the diffusion of tenuously adsorbed chains. The dynamics were described by a nonexponential rate process. The relaxation times calculated were found to increase with increasing polymer to latex feed weight ratio. Kinetic constraints were inferred to play a crucial role in controlling the overall dynamics. A higher polymer to latex feed weight ratio was considered to enhance these kinetic constraints. Copyright 1999 Academic Press.