SOLVENT DEPENDENCE OF THE CHAIN DIMENSIONS OF POLY(NORMAL-HEXYL ISOCYANATE)

Poly(n-hexyl isocyanate), known to be a stiff helical polymer, is found experimentally to have persistence lengths of from 20 to 40 nm, depending upon the solvent in which the measurements are made. The origin of this solvent dependence is hypothesized in the present work to be due to a local interaction of polar solvents with the chain backbone, giving rise to greater torsional oscillations around the backbone bonds. NMR line-width measurements made on the same sample of polymer in a variety of solvents support this idea by showing that the magnitude of the polymer's local motion is correlated with solvent polarity. © 1990, American Chemical Society. All rights reserved.