Crystal-like pattern formation in polymerization-induced phase separation

Abstract

A unique domain structure was found in liquid-liquid phase separation induced by radical polymerization of 4-chlorostyrene monomer in the presence of random copolymer poly(dimethylsiloxane-co-diphenylsiloxane). Droplets with a narrow size distribution were generated by phase separation, and these droplets hardly coalesced by collisions. With the growth of droplet size, droplets gradually filled the space and spontaneously arranged themselves in a regular array like a crystal. The mechanism of regular array formation was discussed based on the large difference in viscoelastic properties between two segregating components.

Analysis of the Phase Separation Induced by a Free-Radical Polymerization in Solutions of Polyisobutylene in Isobornyl Methacrylate

“…A thermodynamic analysis of phase separation during a free-radical polymerization must take into account the polydispersity of the modifier, particularly if it is a low molar mass polymer (PIB, polyethylene waxes, 12,13 random copolymers of dimethyl and diphenylsiloxane [16][17][18] ). In this situation, coexistence curves differ significantly from the initial cloud-point curve due to the fractionation of the modifier between both phases.…”

Kinetics of the Free-Radical Polymerization of Isobornyl Methacrylate in the Presence of Polyisobutylenes of Different Molar Masses

“…2,3 Examples of similar systems that have been described in the literature are solutions of polyethylene in different solvents such as butyl methacrylate, 4 styrene, 5,6 and isobornyl methacrylate, 7 solutions of polystyrene in 2-chlorostyrene, 8,9 and solutions of poly(dimethylsiloxane-co-diphenylsiloxane) in 4-chlorostyrene. 10 In some of these systems the linear polymer is added to improve properties of the other linear polymer generated by polymerization. This is the case of HIPS where polybutadiene is added to generate a dispersed rubbery phase that improves the toughness of polystyrene.…”

Crystal-like Array Formation in Phase Separation Induced by Radical Polymerization

“…In a preliminary work, we found a unique structure forming during phase separation induced by radical polymerization of 4-chlorostyrene monomer in the presence of random copolymer poly(dimethylsiloxane- co -diphenylsiloxane) . The pattern exhibited high regularity and symmetry, which made a striking contrast to previously known nonsymmetrical patterns formed during polymerization-induced phase separation.…”

“…An incorrect value of ( M w / M n ) r was given in ref . The value was obtained carelessly with using a SEC that did not fit well for low molecular weight range.…”