Synthesis of a Homopolymer of Oligo(p-phenyleneethynylene) Attached to Alternate Carbons of a Main Chain Polyethylene and Its Liquid-Crystalline and Optical Properties

A homopolymer of oligo(p-phenyleneethynylene)s OPE-attached polyethylene (OPE-PE) was prepared through the thermal addition polymerization of the vinyls in a synthesized mono-vinyl end-capped OPE. The liquid-crystalline and optical properties of the synthesized homopolymer of OPE-PE were studied using polarizing optical microscopy (POM), wide-angle X-ray diffraction (WAXD), ultraviolet-visible (UV-vis) absorption, photoluminescence excitation (PLE) and photoluminescence (PL). The results show that the arrangements of the rigid side chains in the homopolymer of OPE-PE are affected by the flexible main chains in both liquid and solid states. Through a suitable treatment of the film, the formation of aggregates and excimers in the solid state can be avoided. This result provides a new method to eliminate the formation of aggregates and excimers in the active layers of organic light-emitting diodes (OLED) devices, and this kind of homopolymer with OPE side chains could be a promising class of light-emitting materials