Experimental observation of crossover from noncondensed to counterion condensed regimes during free radical polyelectrolyte copolymerization under high-composition drift conditions.

By combining detailed online kinetics of comonomer consumption with light scattering, viscosity, and conductivity data, experimental detection of changing degrees of counterion condensation was achieved by using comonomers of widely separated reactivity ratios that produced large composition drifts during synthesis. Endproducts of such syntheses contained mixtures of chains of widely varying linear charge density. Evidence of a smooth transition from noncondensed to counterion condensed regimes was found during individual synthesis reactions of copolymeric polyelectrolytes, or "copolyelectrolytes", from the changing slope of conductivity versus [ionic comonomer] incorporated in the high-composition drift syntheses.

Monitoring the synthesis and properties of copolymeric polycations.

The kinetics; evolution of molar mass; solution conductivity, sigma; intrinsic viscosity; and average composition drift; and distribution were determined by monitoring the synthesis of copolymeric polycations of acrylamide (Am) and [2-(acryloyloxy)ethyl]-trimethylammonium chloride (Q9). The quantitative relationship between diminishing sigma and charged co-monomers incorporation was monitored for the first time and provided novel data on counterion condensation, which occurs gradually over a broad composition regime. This new capability allows predictions concerning the relationship between copolymer composition and linear charge density, xi, to be tested and models of trivariate mass, composition, and xi distributions to be built.