Phase-controllable topochemical polymerization of liquid crystalline epoxy according to spacer length

초록

Liquid crystalline epoxies (LCEs) have received considerable attention owing to their potential applications in heat dissipation in electronic devices. Herein, we report novel LCE systems (LCEn, n = spacer length) comprising bifunctional phenyl benzoate LC monomers with different spacers that are cured using an imidazole curing agent. Based on microstructural analyses, the lengths of the different alkyl chains considerably affect the LC phases. LCE4 and LCE6 exhibit smectic orientations, whereas LCE8 exhibits a nematic orientation during polymerization. All LCEn samples exhibit high thermal conductivities and superior thermal properties because the mesomorphic assemblies enhance their strong intra- and intermolecular interactions. LCE4, in particular, which displays a compact orientation order, exhibits remarkably high thermal conductivity (0.49 W m(-1) K-1). Furthermore, the LCEn samples exhibit superior thermal conductive behavior to those of existing commercial polymers. These results suggest the potential of LCEs as electronic materials based on their thermomechanical properties and high thermal conductivities.

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