Analytical theory and Monte Carlo simulations of gel formation of charged chains

Abstract

We analyze the formation of gels by linear charged chains with associating end groups, termed charged telechelics, by analytical and computational methods. Linking chains together leads to polydisperse mixtures of branched macromolecules that form a sol fraction. At a certain fraction of associated end groups a macromolecule spanning the whole system or gel appears. In this work we study how the charge density of the telechelic backbone, controlled via the pH, and the salt concentration modifies the gelation transition. We use a mean field model of chain association which includes self-consistently the electrostatic interaction through a generalized linear response theory approach. Our analytic results compare well with our Monte Carlo simulations. We find that the number of chains connected to i chains after the gelation is rather monodisperse generating highly homogeneous networks of charged chains.