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Dielectric and Optical Properties of Polymer Confined in Random Porous Matrices

Published online by Cambridge University Press:  26 February 2011

Fouad Aliev*
Affiliation:
faliev@rrpac.upr.clu.edu, University of Puerto Rico, Physics, Department of Physics, PO BOX 23343, UPR, San Juan, PR, 00931, United States, 1 787 7640000, ext. 7554, 1 787 7567717
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Abstract

We report the results of the investigations of the influence of confinement on the glass transition and dynamics of the a-relaxation processes in poly(octylmethacrylate) (POMA) by dielectric spectroscopy. The polymer was synthesized directly in pores of the porous glass matrix with interconnected and randomly oriented pores with an average pore size of 100 nm by free radical polymerization of the monomer. We found that confinement is resulted in the reduction of the glass transition temperature Tg of the polymer. This change in Tg was mainly due to the existence of a developed pore wall-polymer interface and difference in the dynamic behavior of polymer in the surface layers compared to that in the bulk. Complementary light scattering experiments show that in 100 nm matrices containing the polymer an anomalous change in light scattering, which switches the composite from the opaque state to the transparent, in a narrow temperature range around T = 60 °C. These changes could be explained by assuming that at low temperatures (opaque state) the orientational order of the relatively long linear aliphatic side groups is induced by the inner pore surface. The assumption of the formation of the orientationally ordered regions at the pore wall in confined POMA is in agreement with the molecular structures of the polymer and the surface of silica.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

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