Polymer-dispersed liquid crystal nanocomposites comprising montmorillonite clay modified by conducting pentamerous oligoaniline

Abstract

Pentamerous oligoaniline (POA) was protonated with sulfuric acid to form emeraldine salts (ES) and then intercalated in montmorillonite (MMT) CL120 to develop a functional conductive organo-layered material. The characteristics of the modified clay CL120/ES-POA were analyzed by wide-angle X-ray diffraction (WAXD) to find the d-spacing of the MMT layer distance, and by Fourier transform infrared (FTIR) spectroscopy for the oligoaniline functional group in CL120/ES-POA, and highresolution thermogravimetric analysis (TGA) to determine the theoretical intercalation capacity of the modifying agent in the clay. We successfully intercalated the ES-POA into the MMT by ionic exchange reaction. Polymer-dispersed liquid crystal (PDLC) composites were prepared from the modified clay of 1 wt% loaded in the mixtures of 49 wt% photosensitive monomer and 50 wt% nematic liquid crystal (NLC), in a specific case, so as to generate novel functional nanocomposites. The hybridization of CL120/ES-POA clearly improved the electro-optical properties of the PDLCs. In this work, doping CL120/ES-POA at 1 wt% beneficially lowered the driving voltage by almost 70%, increased the transmission contrast ratio by five times and reduced the response time from 4.6 to 0.7 ms at 25 V rms at the expense of the viewing-angle properties.

Fabrication of Oligoaniline-Based Electrically Responsive Polyamide Membranes for High-Performance Molecular Nanofiltration

“…Nevertheless, PANI were usually blended into the membrane due to an ill-defined structure to realize electrical responsiveness, which could generate defects and limit application. In contrast, oligoanilines possess a well-defined molecular configuration, good electro-activity, and favorable solubility in ordinary solvents, − making them promising candidates that can be obtained through synthetic chemistry. Especially, amino-capped oligoanilines can serve as IP membrane-forming amine monomers due to their high chemical reactivity.…”

Liquid crystalline behaviour of self-assembled LAPONITE®/PLL–PEG nanocomposites

“…Hence, clays represent a natural candidate for studying their various LC phases. Indeed, other clays like beidellite, 9 gibbsite, 10 montmorillite 11 and nontronite 12 form more easily liquid crystalline phases, all of them showing predominantly discotic-nematic phases, also because they often have only one type of charge in water (typically negative) and their larger aspect ratio. Laponite, however, has resisted so far to various efforts in sterically stabilizing them such that high enough concentrations to the phase transition to a nematic state could be reached.…”