Ahn, W. Kim, C.Y. Kim, H. Kim, S.C. 2024-01-21T23:38:36Z 2024-01-21T23:38:36Z 2021-09-02 1992-01 0024-9297 https://pubs.kist.re.kr/handle/201004/146700 The thermodynamic phase behavior of blends of a low molecular-weight liquid crystal (LC), 4-cyano-4′-n-heptylbiphenyl (7CB), and each of two amorphous polymers, poly (methyl methacrylate) (PMMA) and polystyrene (PS), was studied as a function of temperature or LC concentration. Phase diagrams for both the binary PMMA/7CB and PS/7CB blends were constructed from DSC and optical microscopic observations showing that 7CB was partially miscible in both PMMA and PS. The study revealed an important observation that there existed a polymer/isotropic LC two-phase state at a given composition besides the polymer/nematic LC two-phase state and the polymer/solid crystalline LC two-phase state. The polymer/isotropic LC two-phase morphology was clearly observed by the phase-contrast optical microscope in the temperature range between the homogeneous single-phase state and the polymer/nematic LC two-phase state, while DSC or cross-polarized light microscopy failed to detect the existence of the polymer/isotropic LC two-phase state. This was also confirmed by a light-scattering experiment. At a low ratio of LC in both the PMMA/7CB and PS/7CB blends, direct transformation between the homogeneous single-phase state and the polymer/nematic LC two-phase state was observed without going through the polymer/isotropic LC two-phase state. ？ 1992, American Chemical Society. All rights reserved. English Calorimetry Liquid crystals Phase diagrams Polymethyl methacrylates Polystyrenes Thermal effects Thermodynamics DSC Polymer blends Phase Behavior of Polymer/Liquid Crystal Blends Article 10.1021/ma00045a028 1 Macromolecules, v.25, no.19, pp.5002 - 5007 Macromolecules 25 19 5002 5007 scopus 2-s2.0-0026927920 Article Calorimetry Liquid crystals Phase diagrams Polymethyl methacrylates Polystyrenes Thermal effects Thermodynamics DSC Polymer blends polymer-liquid crystal blend phase separation phase contrast