Optical Behaviors of Cholesteric Liquid-Crystalline Polyester Composites with Various Chiral Photochromic Dopants

Abstract

New developments in the field of chiral nematic liquid crystals, such as color displays, are now being widely proposed. This article describes the tunable incident reflection band based on composite materials of low-molecular-weight chiroptical dopants and polymeric networks. These materials have advantages including easily manageable color according to a change in the helical pitch of the cholesteric liquid crystal upon exposure to light. A series of novel chiral dopants of isosorbide derivatives containing photochromic groups and three new main-chain liquid crystalline polyesters were synthesized and identified using nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and elemental analyses. The phase-transition temperatures and the liquid-crystal phase determination of the synthesized polymers were estimated using DSC, WAXD, and POM analyses. The influence of the dopant concentrations and the solubility in a liquid crystalline polymer blend were also studied. The reflection band of the cholesteric liquid crystalline composites could be adjusted and tuned with a wide range of color variation across the entire visible region. A real image recording of the chiral photochromic liquid crystalline polymer blend was achieved by exposing it to UV light through a mask.

Cholesteric Polymer Scaffolds Filled with Azobenzene-Containing Nematic Mixture with Phototunable Optical Properties

“…Another class of responsive cholesteric materials is that of photochromic systems based on azobenzene derivatives − or other types of photochromes − introduced into the low-molar-mass or polymer LC matrices. This approach is fruitful for obtaining photosensitive films with photovariable helix pitch, − ,− the possibility of holography recording, − and a variety of other applications and effects. ,, …”

Light Intensity-Selective Photopolymerization and Photoisomerization for Creating Colorful Polymer-Stabilized Cholesteric Liquid Crystal Patterns

“…The presence of the tertiary amino group in 907 can help reduce the oxygen inhibition . The synthesis procedure and characterization data of CA are given in the Supporting Information . Under UV irradiation, the compound CA and its derivatives can perform the E – Z photoisomerization (Figure S1) and allow specific [2 + 2] photocycloaddition and photopolymerization to occur especially at a high concentration.…”

Synergistic interaction of renewable nipagin and eugenol for high performance aromatic copoly(ether ester) materials

“…[7][8][9][10][11] Nipagin and eugenol are two naturally occurring building blocks, which exist in campanulaceae plant and clove, respectively. 12,13 These two starting materials have been found widespread applications in fields of liquid crystalline material, 14,15 epoxy resin, [16][17][18] benzoxazine, 19,20 coating, 21,22 and Li-S battery. 23 Because of the multifunctionality (phenol and vinyl) and renewable nature of nipagin and eugenol, our group started to investigate polyester materials starting from them, whose thermal, crystalline, mechanical and degradable properties have been systematically investigated.…”