Characterization and Thermal Behaviour of Polymer-Dispersed Liquid Crystals

Abstract:

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The thermal behaviour of polymer dispersed liquid crystals (PDLC), blends of poly(ethylene-co-methylacrylic acid) (PEMA) with 4-(n-hydroxypropoylxy)-4'-cyanobiphenyl (H3CB) prepared by solvent-induced phase separation (SIPS) method, has been characterized using differential scanning calorimetry (DSC) and polarized light microscopy (POM). Study shows that the concentration of the mixture of PEMA/ H3CB must be least 30%, which will exhibit nematic to isotropic transition phase during heating or cooling. Above 30 wt % 3CB the mixtures exhibited nematic phase, and this was detected as a splitting of the nematic-isotropic peak in the DSC thermograms. The clearing temperature of the PEMA/H3CB mixtures was higher than that of pure H3CB’s, the average increasing being 14°C, which is the evident that the polymer matrix could stable the nematic phase. This behaviour is in contrast with other reports about polymer-dispersed liquid crystals. In addition, thermal decomposition was also studied by thermogravimetry in nitrogen environments. A double-stage decomposition process was found in nitrogen atmosphere, and this was mainly due to H3CB for the first step and the PEMA decomposition for the second step.

Info:

Periodical:

Advanced Materials Research (Volumes 152-153)

Edited by:

Zhengyi Jiang, Jingtao Han and Xianghua Liu

Pages:

284-287

DOI:

10.4028/www.scientific.net/AMR.152-153.284

Citation:

X. G. Han et al., "Characterization and Thermal Behaviour of Polymer-Dispersed Liquid Crystals", Advanced Materials Research, Vols. 152-153, pp. 284-287, 2011

Online since:

October 2010

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Price:

$35.00

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