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Eco-friendly PDLC composites based on chitosan and cholesteryl acetate

Year: 2021

Journal: J. Mol. Liq., Volume 321, JAN 1

Authors: Ailincai, Daniela; Marin, Luminita

Organizations: Romanian National Authority for Scientific Research, MEN-UEFISCDI grant [PN-IIIP1-1.2-PCCDI-2017-0569, 10PCCDI/2018]

Keywords: Chitosan; Cholesteryl acetate; PDLC composites; Bio-friendly; Cholesteric

A series of live eco-friendly PDLC composite films based on cholesteryl acetate liquid crystal and chitosan were obtained and characterized. The resulted composites were evaluated in terms of structure and morphology by FTIR and RAMAN spectroscopy and scanning electron microscopy, while their thermotropic behavior was evaluated by polarized optical microscopy and differential scanning calorimetry. Moreover, the contact angle and surface free energy components were measured and calculated. All the data revealed that chitosan, through the presence of hydroxyl, amine, and amide groups in its structure, has the ability to constrain the cholestelyl acetate liquid crystal to grow as radial droplets, perturbing its supramolecular chiral ordering. The size of the droplets and their density depended on the mass ratio between the polymer and the liquid crystal almost in all cases, the micrometric droplets having diameter from 5 to 8 mu m, sizes which are the most recommended for optoelectronic applications. By changing the mass ratio between the components, PDLC composites with different hydrophobicity were obtained, consequence of both, their chemical composition and their geometrical microstructure of their surface. (C) 2020 Elsevier B.V. All rights reserved.