Comparison of the Thermotropic and Solution Behavior of Six-Arm Star and Comb Poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate

Abstract

“Six-arm star” poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s with 13−112 (gel permeation chromatography, GPC, relative to linear polystyrene) or 23−756 (GPC using a light scattering detector) repeat units were synthesized from the hexafunctional initiator, 1,2,3,4,5,6-hexa((4‘-methyl(2‘ ‘-bromopropionate)phenoxymethyl)benzene, by atom transfer radical polymerization of 11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate, followed by fractionation to narrow the polydispersity to 1.06−1.57. The absolute molecular weight, size, and shape of these polymers were characterized by light scattering in CH2Cl2, and their thermotropic behavior was analyzed by differential scanning calorimetry; both types of properties were compared to those of the other architectures, especially the corresponding comb poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s with six branches. The solution and thermotropic behavior of the six-arm star and comb polymers are similar.