Preparation of composites of liquid-crystalline matrix of poly(p-phenylene-sulfoterephthalamide) and CaCO3byIn situmineralization

Abstract

Liquid-crystalline (LC) hydrogels were obtained from an aqueous solution of poly(p-phenylene-sulfoterephthalamide) (PPST) by the addition of calcium ions (Ca2+). The critical hydrogel formation ratio of Ca2+ to the sulfonic acid group in PPST (crtRCa = [Ca2+]/[ ‐SO3−]) depended on the concentration of PPST, and was independent of the molecular weight of PPST. When the LC hydrogel was prepared at a concentration of 0.5 wt % and crtRCa = 0.6, and was exposed to ammonium carbonate vapor for 96 h, all Ca2+ in the LC hydrogel were converted into calcite crystals. The alternate soaking process for the LC hydrogel induced the formation of two mesocrystal morphologies on and in the Ca2+ cross-linked LC hydrogel. Plate-like calcite mesocrystals grew at the hydrogel/solution interface and cubic mesocrystals were present in the inner space of the hydrogel, thus composites with some ordered structures of LC matrix and CaCO3 have been prepared through in situ mineralization. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41455.