Correlation of self-assembly and thermal conducting properties of PEG-backbone polyether with a room temperature mesophase

Abstract

Recently, liquid crystalline polymers (LCPs) with distinct properties derived from self-assembled structures have gained attention as thermal conducting materials. In this study, a series of liquid crystalline monomers having an epoxide through various spacer lengths (n = 4–9) from a mesogen structure were synthesized, and their polymers, side chain LCPs, were fabricated through anionic ring-opening polymerization (AROP). The number average molecular weights (M_ns) and polydispersity index of the LCP series were successfully adjusted to 10 000 and 1.1, respectively, to investigate phase transition without molecular weight effects, by controlling the AROP. The LCPs exhibited glass transition below room temperature at certain spacer lengths (n ≥ 5), and X-ray diffraction investigation revealed that they possessed self-assembled microstructures. Further, they showed fairly high thermal conductivity values (0.42–0.46 W m⁻¹ K⁻¹) which are more than two times higher than that of polyethylene glycol, derived from the ordered structure corresponding to their main chain polymer.