Thermally reversible materials based on thermosetting systems modified with polymer dispersed liquid crystals for optoelectronic application

Abstract

The main aim of this research was the generation of new intelligent materials, in this case thermoreversible material, based on an epoxy matrix modified with liquid crystal for optoelectronic application. The samples were prepared by the reaction-induced phase separation (RIPS) of a solution of 4(-(hexyloxy)-4-biphenyl-carbonitrile (HOBC) and polystyrene (PS) in diglicydylether of bisphenol-A epoxy resin (DGEBA). The systems were cured with a stoichiometric amount of an aromatic amine hardener, 4,4(-methylene bis(3-chloro-2,6-diethylaniline) (MCDEA). Taken into account results obtained by differential scanning calorimetry (DSC) and transmission optical microscopy (TOM) equipped with a hot stage it was found that depending on morphology generated by RIPS of HOBC/thermoplastic particles in the epoxy matrix thermally reversible light scattering (TRLS) material can be obtained.

Nanoindentation study of interphases in epoxy/amine thermosetting systems modified with thermoplastics

“…Different morphologies on epoxy/amine and thermoplastic phases can be appreciated, being rougher the thermoplastic surface, due to the different cutting behavior during sample preparation. It is well known that the epoxy/amine-aPS mixture, with the amine MCDEA, generates reaction induced phase separation through curing of the epoxy matrix [49][50][51]. Systems with semicrystalline polymers show the initial contact border without any signs of reaction induced phase separation, so, a more detailed study of diffusion was carried out on the system with aPS by performing larger scale AFM scans.…”

Multifunctional Thermally Reversible Nanostructured Thermosetting Materials Based on Block Copolymers Dispersed Liquid Crystal

“…[24][25][26] Whereas several studies have shown a new family of polymer-dispersed LCs, [27][28][29][30] where the LC is dispersed in a thermoplastic/thermoset matrix, to the best of our knowledge, the possibility of using block copolymers as modifiers in thermoset systems and their ability to act as thermally reversible nanostructured thermosetting materials have not been reported yet. Taking into account the work done by Hoppe et al [27,28] and our previous papers, [10][11][12][29][30][31][32][33] the main aim of the present contribution is to investigate the possibility of obtaining novel meso/nanostructured thermosetting materials, which can be thermally reversible based on a thermosetting system modified with a block copolymer and a nematic lowmolecular-weight LC. Bisphenol A-type epoxy resin, modified with an amphiphilic block copolymer based on polystyrene and poly(ethylene oxide) (PSEO) and a low-molecular-weight nematic LC, 4 0 -(hexyl)-4-biphenylcarbonitrile (HBC), has been cured with a stoichiometric amount of an aromatic amine hardener, m-xylylenediamine (MXDA).…”

Effects of surfactant and molecular weight of polyol on grating formation and switching of holographic PDLC

“…where l 31 is interpreted as the ability of one dispersed component (1) to displace the matrix (2) from the surface of a second component (3). When l 31 is positive, component 3 envelops component 1 in matrix 2, but when l 31 is negative, the two dispersed phases remain separate.…”

“…Polymer-dispersed liquid crystals (PDLCs) are composed of micron-size liquid crystal droplets dispersed in a continuous polymer matrix, which have been extensively investigated for their particular electro-optical properties. [1][2][3] Holographically formed polymer dispersed liquid crystals (HPDLC) have attracted considerable interest owing to their morphology and electro-optic properties. [4][5][6][7] HPDLCs have potentials in numerous electro-optic applications such as reflective flat-panel displays, optical data storage, diffractive optics, and many others.…”