| Institution: | 1. Institute of Chemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91501970 RS, Brazil;2. Department of Chemistry, University of York, York, United Kingdom
School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT United Kingdom;3. Department of Physics, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil;4. Faculty of Pharmacy, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil |
| Abstract: | Polar-terminated 3,5-diarylisoxazole liquid crystals (ILCs) were synthetized and characterized. ILCs are composed by rigid core 3,5-diarylisoxazol, alkyl chain and polar-terminated flexible spacer. Hydroxyl-, ketal- and 1,2-diol-terminated ILCs rendered smectic C and A mesophase, while bromine-terminated ILCs showed smectic A and B mesophase, for monosubstituted and linear ILCs. For branched alkyl chain monotropic SmA was detected and for disubstituted ILCs no mesophase was detected. Out-of-layer fluctuations (OLFs) are discussed based on X-ray diffraction date and textures. The OLFs are dependent on the bromine atom hardness, hydrogen bonding through collective actions and conformational effects at the interface between layers. Smectic translational order parameter (TOP) Σ was also obtained for orientated bromine- and hydroxyl-terminated ILCs and related it with OLFs. For 1,2-diol-terminated ILCs two SmC sublayers were founded, probably related to the intramolecular hydrogen bond favoring the 5-membered and 6-membered formation. |
