Phase diagrams of thermally stable, polymer‐dispersed liquid crystals: Exploring the impact of chain length and chemical structure

Abstract

Polymer-dispersed liquid crystals (PDLCs) have garnered significant interest and motivated the investigation of the phase behavior of thermally stable smectic liquid crystals (LCs) via thermally induced phase separation (TIPS). In this study, we examined a series of two, biphenyl-based smectic LCs suitable for high temperature polymer blend processing. Phase diagrams for LC/polystyrene (PS) blends at various compositions (0-60 wt%) were constructed. Less than 15 wt% of 8B8 (1,1 0 -biphenyl-4,4 0 -diyl dioctanoate) LC in PS led to good polymer miscibility, while phase separation was induced at concentrations higher than 15 wt%. The LC concentration at saturation decreased with increasing aliphatic chain length. We also investigated the chain length (C6-C16) effect on the PS glass transition temperature (T g ) at the LC saturation point. The T g increased with increasing chain length due to reduced plasticization. We further examined the role of chemical structure (relatively less polar ether vs. more polar ester) on the phase diagram regions and the T g of the nonpolar PS matrix, respectively. It is anticipated that these LC/PS phase diagrams will benefit elevated temperature processing for TIPS by highlighting the role of LC chemical structure and chain length on blend morphology. POLYM. ENG. SCI., 56:388-393, 2016.

Compatibilizing effects for semicrystalline polymer‐infiltrated amorphous polymer matrix: Mechanical (toughness), thermal, and morphological behavior of compatibilized polypropylene/polycarbonate blends

“…Even immiscible polymer blends are partially miscible with increasing ratio 11 and the miscibility (solubility) increases as a function of temperature. 24,25 As the temperature approaches the T g of blends during DSC scans, the miscibility gradually increases, thereby leading to lower T g than anticipated. There should be two T g 's for typical immiscible blends.…”

“…In addition to mechanical properties, the thermal properties of polymeric materials are of great importance due to their transition temperatures and crystallization behaviors. Even immiscible polymer blends are partially miscible with increasing ratio and the miscibility (solubility) increases as a function of temperature . As the temperature approaches the T g of blends during DSC scans, the miscibility gradually increases, thereby leading to lower T g than anticipated.…”

The importance of structure property relationship for the designing of biomaterials using liquid crystal elastomers

“…[19][20][21] LCEs can also mimic vital features of endogenous tissue thus satisfying the prerequisites biocompatibility and biodegradability, mechanical properties, cell spatial growth, cell alignment, and long-term studies that are considered as tissue engineering systems. [22][23][24] LCs have long been used and/or incorporated into materials to create composites, ensure better processing, [25][26][27][28] introduce LC properties, create chemical sensors, [29][30][31] and biosensors, 32,33 soft actuators, [34][35][36][37][38] light driven motors, 39,40 as responsive building blocks for guiding 2D cell growth, 41,42 promoters of cell orientational order, [43][44][45] or to control the dynamics of bacteria. 46,47…”

Physical Models from Physical Templates Using Biocompatible Liquid Crystal Elastomers as Morphologically Programmable Inks For 3D Printing

“…[22] Liquid crystalline (LC) moieties have been introduced to polymers as promoters for better processing, or to introduce LC properties. [23][24][25][26] LC materials have thus been studied as actuators, [27−29] sensors [30−33] and biosensors, [34,35] as regulators for bacteria dynamics, [36,37] or as guides to induce 2-D cell growth. [38][39][40] Abbott and coworkers as well as Shashidhar and coworkers reported that the orientational order of LCs can be coupled to cells, making LCs promoters of cell orientational order.…”