One Dimensional PMMA Nanofibers from AAO Templates. Evidence of Confinement Effects by Dielectric and Raman Analysis

Abstract

The aim of this work is to examine the influence of confinement effects on the chemical and dielectric properties of nanostructured polymethylmetacrylate (PMMA) in comparison to the bulk. In general, authors have focused their research on isotactic PMMA and only a few have studied PMMA with other tacticity so, in consequence, we have chosen a PMMA with main content of syndiotactic form. One-dimensional polymer nanostructures of PMMA have been prepared by infiltration into AAO templates with different dimensions of pores: 28, 35, and 65 nm. Laboratory-made, electrochemically fabricated porous materials have been used as confining systems with very well-defined geometry. Scanning electron microscopy micrographs present the regularity of the obtained nanofibers and show the appropriate, homogeneous filling of the nanocavities. As methods of physical and chemical characterization we have chosen broadband dielectric and Raman spectroscopy. By dielectric spectroscopy experiments we observe that the relaxation behavior of confined PMMA within templates of cylindrical nanopores differs from that of the bulk polymer. By Raman spectroscopy, we are able to visualize changes in the chemical structure of PMMA. Results obtained by using both spectroscopic methods are compatible.