MolecularOrientation of lonlc Poymer in a Polyion Complex Type Nonbilayer Film with an lnverted Hexagonal Phase

Abstract

A polyioncomplex was prepared from a bilayer forming amphiphile, dimethyldioctadecylam-monium bromide, and poly(sodium styrenesulfonate)1abeled with nitroxide radical on a small amount of methacrylate residue in the polymer. Anonbilayerfilm comprised of micro-rods was prepared by usual solvent cast of the polyion complex and cholesterol(80: 20(wlw)). The ESR spectra of thefi1m depended on the direction of applied magnetic field during measurement. Each spectra was changedby uni-axially stretch of the film due to the alternation of the mo1ecular axis of the ionic polymer. The change in the spectra suggested that the longitudinal axis of the ionic polymer was perpendicular to the fi1m surface in a similar manner as the micro-rod. The orientation of the polymer molecule supports an invertedhexagonal type model in which the molecule of ionic polymer would extend linearly along the hydrophilic core of the rod.