A homeotropic main-chain tolane-type liquid crystal elastomer film exhibiting high anisotropic thermal conductivity?

Soft Matter Pub Date: 2017-07-03 DOI: 10.1039/C7SM01154G

Abstract

The development of pure polymeric films with anisotropic thermal conductivities for electronic device packaging applications has attracted intense scientific attention. In order to enhance the polymeric film's normal-direction thermal conductivity, homeotropic alignment of macromolecular chains is the primary concern. One of the promising preparation strategies is to perform in situ photopolymerization of homeotropic-oriented liquid crystal monomers. In this work, we design and synthesize a novel tolane-core thiol–ene-tailed liquid crystal monomer. Benefitting from the conjugated and extended tolane π-system of the mesogenic core and length extension of the terminal aliphatic tails, the normal-to-plane thermal conductivity value and the thermal conductivity anisotropy value of the corresponding cross-linked main-chain end-on liquid crystal polymer (xMELCP) film reach 3.56 W m?1 K?1 and 15.0, respectively. Compared with the data of a previously reported ester-type thiol–ene xMELCP film, the two primary values of this novel tolane-type thiol–ene xMELCP material are increased dramatically by 46% and 29%, respectively.

Graphical abstract: A homeotropic main-chain tolane-type liquid crystal elastomer film exhibiting high anisotropic thermal conductivity
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