High Refractive Index and Excellent Transparent Polyarylates Containing Pendant Groups and Thiophene

Abstract

Polymers that exhibit both a high refractive index and superior transmittance are critically sought for optoelectronic device applications. Polyarylates are considered one of the most promising classes of optical materials for such purposes. Nevertheless, the demand for polyarylates with enhanced refractive indices and elevated light transmission levels is growing. This study introduced a series of innovative polyarylates synthesized via nucleophilic reactions involving bisphenol with a pendant cardo structure and acid chloride derived from a biobased diacid (2,5-thiophenedicarboxylic acid). These polyarylates demonstrated a relatively high refractive index (n_d = 1.695), excellent light transmission (T_400 nm > 86% and T_avg > 92%), and ideal low dispersion (Abbe number = 23). The elevated refractive index can be attributed to the high molar polarizability of thiophene, whereas the exceptional transmittance is credited to the bulky cardo-ring structure that minimizes interactions between polymer chains. Furthermore, these polyarylates displayed excellent thermal properties and solubility, enhancing their processability. This research offers a viable strategy for developing high-refractive-index polymers with excellent transmittance for optical applications.