(Chem.Commun.) Homeotropically-Aligned Main-Chain and Side-on Liquid Crystalline Elastomer Films with High Anisotropic Thermal Conductivities
writer：Wang, M.; Wang, J.; Yang, H.*; Lin, B.; Chen, E.; Keller, P.; Zhang, X.; Sun, Y.
keywords：LCE
source：期刊
specific source：Chemical Communications, 2016, 52, 4313-4316.
Issue time：2016年
In this
work, we synthesize nematic main-chain and side-chain
side-on crosslinked liquid
crystalline polymer films (xMELCP and xSSLCP) by in situ photopolymerization of LC thiol-ene monomer T6E5 and LC acrylate monomer A444 oriented by AC electric fields respectively.
The macromolecular main chains are forced to align along the normal directions
of the obtained films,
in order to enhance the thermal conductivities in the normal directions. Both POM observations and 2D-WAXS investigations
of the xMELCP and xSSLCP films confirm homeotropic orientations of the
mesogenic groups in LCPs, and thus of the macromolecular backbones because of
the coupling between the macromolecular chains and the mesogenic groups.
Evaluated by laser flash analysis
method, the room temperature thermal conductivities of these two xLCP films in
the film normal direction are both dramatically higher than those along the
horizontal direction. In particular, the main-chain thiol-ene xMELCP film shows the
highest thermal conductivity anisotropy value (λ///λ⊥ = 11.6). These novel xLCP materials have potential
applications as anisotropic thermal insulators.