The design, synthesis and order-enhanced emission of luminescent liquid crystalline polymers based on a “jacketing” effect

Abstract

To explore the optoelectronic properties of liquid crystalline polymers (LCPs), two luminescent liquid crystalline polymers (LLCPs) with high-efficiency emission in the solid state, namely poly([3-(4′,4′′-dibutyloxy)tetraphenylethylene]styrene) (PSTPE) and poly(3,5-bis[(4′,4′′-dibutyloxy)tetraphenylethylene]styrene) (PS2TPE), on the basis of aggregation-induced emission (AIE) and a “jacketing” effect, are successfully prepared through radical polymerization under mild conditions. The chemical structures of the monomers and polymers are identified via nuclear magnetic resonance (NMR), MALDI-TOF MS and gel permeation chromatography (GPC) characterization. AIE and aggregation-enhanced emission (AEE) behavior are shown by the resulting LLCPs PSTPE and P2STPE, respectively. Meanwhile, the results of wide-angle X-ray diffraction (WAXD) analysis reveal that the LLCPs can form typical smectic phases. More interestingly, both polymers show higher emissive efficiency after thermal annealing. Further, the results of WAXD and ultraviolet-visible (UV-vis) studies indicate that the polymers can form more ordered structures, which means that an increase in ordering can enhance emission.