Self-assembling behaviour of new functional photosensitive cinnamoyl-based reactive mesogens

• Published in: Liquid crystals Vol. 47; no. 14-15; pp. 2276 - 2291
• Main Authors: Bubnov, Alexej, Cigl, Martin, Sedláčková, Nela, Pociecha, Damian, Böhmová, Zuzana, Hamplová, Věra
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 07.12.2020; Taylor & Francis Ltd
• Subjects: cinnamoyl group; Irradiation; Light irradiation; Liquid crystal; Liquid crystals; Molecular structure; Organic materials; Phase transitions; photosensitive materials; Photosensitivity; reactive mesogen; self-assembling behaviour; Self-assembly; Small angle X ray scattering; Transition temperatures
• ISSN: 0267-8292; 1366-5855
• DOI: 10.1080/02678292.2020.1783586

One of the most exciting classes of organic materials that is able to self-assemble at nanoscopic scale are those exhibiting the liquid crystalline (LC) behaviour which can be distantly tuned by an external stimulus. Under UV/Vis light irradiation, the reversible photoisomerisation process can take place if the compounds possess the photosensitive group, e.g. N=N or cinnamoyl group incorporated in their molecular structure. This can drastically affect the LC behaviour. However, the compounds possessing the cinnamoyl fragment with C=C double bond are capable of both photoisomerisation and photocycloaddition processes. Several cinnamoyl-based reactive mesogens with polymerisable vinyl group have been designed; their mesomorphic and structural behaviour have been studied. Depending on the molecular structure, the reactive mesogens exhibit nematic, orthogonal smectic A and tilted smectic C phases; the kinetics of the phase transition temperatures has been checked. The structure of the mesophases is confirmed by small-angle X-ray scattering. The main objective of the present work is to contribute to better understanding of molecular structure - mesomorphic property relationship for new functional cinnamoyl-based photosensitive reactive mesogens which can be further used for design of smart self-assembling macromolecular materials.