Peripheral chain length-dependent complex phase behaviour in C3-symmetric hexa-alkylated liquid crystals. Issue 8 (21st June 2018)

• Record Type: Journal Article
• Authors: Nguyen, Manh Linh; Kim, Ho-Joong; Cho, Byoung-Ki
• Is Part Of: Liquid crystals. Volume 45:Issue 8(2018)
• Page Start: 1196
• Page End: 1209
• Publication Date: 2018-06-21
• Subjects: Columnar liquid crystal -- smectic liquid crystals -- C3-symmetric liquid crystals -- triazolyl mesogen; Liquid crystals -- Periodicals; 548.905
• DOI: 10.1080/02678292.2018.1425491
• Languages: English
• ISSNs: 0267-8292

Abstract

ABSTRACT: We report the thermal and self-assembly properties of C3 -symmetric liquid crystalline (LC) molecules consisting of a conformationally tunable triazole-based mesogen and six-fold alkyl chains. Unlike the LC compound (1 ) based on non-crystallisable octyl chains, 2 and3, which have crystallisable dodecyl and tetradecyl chains, respectively, exhibit a cold crystallisation which only takes place under slow heating conditions (2°C/min). In contrast with the vertically interdigitated lamellar crystalline phase of1, a laterally interdigitated bilayered lamellar structure driven by the crystallisation of the dodecyl or tetradecyl chains is observed in the cold crystallisation temperature range. In addition to their crystalline morphology, 2 and3 show LC morphological behaviour distinct from that of1, 2 and3 exhibit a hexagonal columnar LC phase consisting of T-shaped conformers rather than the lamellar LC phase of1 . The morphological transformation from the lamellar (1 ) to the columnar phase (2 and3 ) can be rationalised by the alleviation of the conformational energy of the longer alkyl chains. Consequently, the simple variation of alkyl chain length in the C3 -symmetric LC system results in contrasting thermal and assembly properties in the crystalline and LC phases. GRAPHICAL ABSTRACT: