E7 nematic liquid crystal encapsulated in a polymeric photonic crystal

Abstract

This study presents the synthesis and characterization of nano encapsulated liquid crystals in the polymer (nano-ELCP) obtained by the soap-free emulsion polymerization of the system styrene (ST) and acrylic acid (AA) in the presence of the liquid crystal E7 (LC). The obtained emulsion and the photonic crystal film (PC) were characterized by optical microscopy, SEM, DLS, UV–Vis, DSC, TEM, GPC, TGA, and fluorescence spectroscopy to highlight the encapsulation of E7 in the polymer particles and their properties. The DLS and SEM analyses confirmed a narrow polymer particle size distribution and the possibility to form highly arranged PCs, which contain the dispersed LC. The DSC, TEM, and TGA analyses sustain the encapsulation of E7 with an LC content of 11.87 % and 25.19 % (weight %) for ST-AA-E7-1 and ST-AA-E7-2, respectively. An increase in the fluorescence response was demonstrated for the polymer encapsulated LC which can be attributed to PCs that augments the intensity of the nematic crystal fluorescence response, in the absence of external stimuli.