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B. Mossety-Leszczak, M. Włodarska, H. Galina, M. Dutkiewicz

Thermal and dielectric properties of silsesquioxanes containing mesogenic azo groups

Polimery 2013, No 10, 733


DOI: dx.doi.org/10.14314/polimery.2013.733

Summary

Two spherosilicates having mesogenic moieties were synthesized by hydrosilylation reaction between octakis(hydridodimethylsiloxy)octasilsesquioxane and monovinyl esters with azobenzene mesogenic groups using Karstedt's catalyst. The synthesized silsesquioxanes differed in the length of aliphatic chains connecting the POSS cage with mesogenic groups. The thermal properties and phase behavior of the products were studied using termogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and dielectric relaxation spectroscopy (DRS). The results show that only the spherosilicate with longer aliphatic spacers (C10) between inorganic cage and mesogenic groups exhibits stable liquid crystalline phases during both cooling and heating. This material also shows an additional relaxation process in the dielectric studies, which has been attributed to the higher mobility of mesogenic groups.


Key words: silsesquioxanes, mesogenic groups, azobenzene groups, liquid crystals, dielectric studies, relaxation processes

e-mail: mossety@prz.edu.pl

B. Mossety-Leszczak, M. Włodarska, H. Galina, M. Dutkiewicz (1.92 MB)
Thermal and dielectric properties of silsesquioxanes containing mesogenic azo groups