Chemical Programming of the Domain of Existence of Liquid Crystals. Issue 4 (14th December 2015)

• Record Type: Journal Article
• Authors: Dutronc, Thibault; Terazzi, Emmanuel; Guénée, Laure; Buchwalder, Kerry‐Lee; Floquet, Sébastien; Piguet, Claude
• Is Part Of: Chemistry. Volume 22:Issue 4(2016)
• Page Start: 1385
• Page End: 1391
• Publication Date: 2015-12-14
• Subjects: cyanobiphenyls -- liquid crystals -- phase transitions -- structure elucidation -- thermodynamics; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201503420
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: This work illustrates how enthalpy and entropy changes responsible for successive phase transitions of cyanobiphenyl‐based liquid crystals can be combined to give cohesive free energy densities. These new parameters are able to rationalize and quantify the demixing of the melting and clearing processes that occur in thermotropic liquid crystals. Minor structural variations at the molecular level can be understood as pressure increments that alter either the melting or clearing temperatures in a predictable way. This assessment of microsegregation operating in amphiphilic molecules paves the way for the chemical programming of the domain of existence of liquid‐crystalline phases. Abstract : Changing states : The cohesive free energy density concept (CFED) is applied to thermotropic cyanobiphenyl‐based liquid crystals to establish predictive quantitative correlations between each antagonist segments of the amphiphilic molecules (flexible alkyl tail/rigid aromatic core) and their transition temperatures (solid→liquid crystalline/liquid crystalline→ isotropic liquid; see figure).