fig7

Figure 7. Enhancement of k of LCP by controlling molecular structure and by hydrogen bonding. (A-i) Schematic showing effect of chain flexibility and backbone rigidity on the packing of the polymer chain (radius of gyration, R_g). k of configuration with larger R_g (R_g2) is greater than smaller R_g (R_g1) owing to longer thermal transport pathways. (A-ii) Schematic and molecular structures of LC epoxy resins with different ethylene linker lengths cured by mixture of C_x(x = 2-8) diepoxide monomer (mesogen) and diaminodiphenylmethane (DDM). A plot showing thermal conductivity (k) as a function of mass density. The values of k and density depend on the linker length. Reproduced from ref.^[148] under the Creative Commons CC BY-NC-ND License. (B-i) Molecular structure of the liquid crystal monomer (LCM) used in the preparation of polyvinyl alcohol (PVA)-dispersed liquid crystal (PDLC) films. (B-ii) Schematic representation of morphologies of microscopic-ordered arrangements in PDLC films. Layered and spherulite structures are formed owing to hydrogen bond interaction and depending on the concentration of LCM. (B-iii) Polarizing optical microscopy (POM) images of LCM. (B-iv) In-plane thermal conductivity (k_||) as a function of concentration of LCM in PDLC films. Reprinted from ref.^[149], Copyright (2021), with permission from Elsevier.