Thermal Stability of High Molecular Weight Self-Doped Poly(anilineboronic acid)

Abstract

The molecular weight, thermal stability, and conductivity of chemically synthesized, self-doped poly(anilineboronic acid) have been determined. Gel permeation chromatography results indicate a number-average molecular weight of 1 676 000 g mol-1, a weight-average molecular weight of 1 760 000 g mol-1, and a polydispersity of ∼1.05. The high molecular weight is maintained following removal of boronic acid groups via ipso-substitution reactions, suggesting that boronic ester cross-links do not contribute significantly to the high molecular weight observed. According to thermogravimetric analysis results, the thermal stability of self-doped poly(anilineboronic acid) is greater than that of HCl-doped polyaniline and other self-doped forms of polyaniline. Unlike polyaniline, which experiences complete decomposition of the backbone above 400 °C, self-doped poly(anilineboronic acid) remains largely intact and possesses conductivity near 0.01 S cm-1.