Intrinsic high thermal conductive liquid crystal epoxy film simultaneously combining with excellent intrinsic self-healing performance

One kind of side chain liquid crystal epoxy (S-LCE) based on biphenyl mesomorphic unit is synthesized from 2, 2-bis(hydroxymethyl)propionic acid, 4-phenylphenol, and epichlorohydrin. And the intrinsic thermal conductive liquid crystal epoxy film (LCEF) simultaneously combining with intrinsic self-healing performance is then prepared via thiol-epoxide nucleophilic ring-opening reaction and coating method. 1H NMR and FTIR show that S-LCE and LCEF have been successfully prepared. S-LCE presents nematic liquid crystal from room temperature to 160 degrees C. LCEF maintains nematic liquid crystal performance and shows highly intrinsic thermal conductivity & excellent self-healing performance. Thermal conductivity coefficient (lambda) values in vertical direction (lambda(perpendicular to)) and parallel direction (lambda(parallel to)) of LCEF are 0.33 and 1.25 W/mK, respectively, much higher than that of general bisphenol A epoxy resin (E-51, lambda(perpendicular to). of 0.19 W/mK and lambda(parallel to) of 0.65 W/mK). Tensile strength of LCEF is 10.6 MPa, which can maintain at 90.6 % and 61.3 % after one and four cycles of self-healing behavior, respectively. In addition, LCEF presents a wide service temperature range (-9.8-251 degrees C) and good thermal stability (T-HRI of 148.5 degrees C). Simultaneously, LCEF has good transparency, flexibility, and tailorability, expected to be utilized in the fields of flexible electronic devices and intelligent structures. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.yyy

Automated summary

In this study, a side chain liquid crystal epoxy based on biphenyl mesomorphic unit was successfully synthesized, and a liquid crystal epoxy film with thermal conductivity and self-healing properties was prepared. The liquid crystal epoxy showed high thermal conductivity, excellent self-healing performance, wide service temperature range, and good thermal stability. It is expected to have wide application prospects in the fields of flexible electronic devices and intelligent structures.