Cholesteric liquid crystals (CLCs) are a significant class of temperature-responsive photonic materials that have the ability to selectively reflect light of a specific wavelength. However, the fabrication of main-chain CLC oligomers with dramatic reflection band variation upon varying the temperatures remains a challenge. Here, a feasible method for improving and controlling the responsiveness of main-chain cholesteric liquid crystal oligomers by the incorporation of a smectic monomer is reported. The smectic monomer strengthens the smectic character of the oligomers and enhances the magnitude of the change of the pitch as a function of temperature upon approaching the cholesteric-smectic phase transition temperature. The central wavelength of the reflection band can be easily modified by mixing in an additional chiral dopant. This promising method will open the door to the preparation of temperature-responsive photonic devices with excellent responsiveness.
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http://dx.doi.org/10.3390/ijms23063275 | DOI Listing |
Phys Rev E
November 2024
William H. Miller III Department of Physics and Astronomy, Johns Hopkins University, Baltimore 21218, USA.
Composite materials made of polymers and liquid crystals have been widely employed in smart windows, optical filters, and bistable displays. However, it is often difficult to decipher the role of the polymer network architecture on the alignment and the texture of liquid crystals. In this study, we use a simple model system where a small amount of polymerizable liquid crystalline monomer is mixed in a liquid crystal that exhibits both a smectic phase and a cholesteric phase with a large helical pitch.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Centre for Nano and Soft Matter Sciences, Bengaluru 562162, India.
We describe the first investigations on the influence of an imposed network on the photonic band gap (PBG) structure of the liquid crystal (LC) phase through the polymer template technique. The technique consists of using a cholesteric (Ch) phase as a base for photopolymerizing a difunctional monomer, which is then removed after polymerization, leaving only the polymer scaffold template. The templated structure obtained is utilized to adjust the PBG structure of the filled LC material, exhibiting both a one-dimensional PBG (Ch phase) and a three-dimensional PBG structure (TGBC* phase with smectic C* blocks).
View Article and Find Full Text PDFMolecules
October 2024
Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Fukuoka, Japan.
Nanostructured polymer-dispersed liquid crystals (nano-PDLCs) are transparent and optically isotropic materials in which submicron-sized liquid crystal (LC) domains are dispersed within a polymer matrix. Nano-PDLCs can induce birefringence by applying an electric field (-field) based on the reorientation of the LC molecules. If nano-PDLCs are utilized as light-scattering-less birefringence memory materials, it is necessary to suppress the relaxation of the LC molecule orientation after the removal of the -field.
View Article and Find Full Text PDFAdv Mater
June 2024
Key Laboratory of Bio-Inspired Materials and Interfaces Sciences, Technique Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
The osmotic energy, an abundant renewable energy source, can be directly converted to electricity by nanofluidic devices with ion-selective membranes. 2D nanochannels constructed by nanosheets possess abundant lateral interfacial ion-exchange sites and exhibit great superiority in nanofluidic devices. However, the most accessible orientation of the 2D nanochannels is parallel to the membrane surface, undoubtedly resulting in the conductivity loss.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2024
Key Laboratory of Polymeric Materials and Application Technology of Hunan Province, Key Laboratory of Advanced Organic Functional Materials of Colleges and Universities of Hunan Province, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China.
Chiral luminescent liquid crystals have attracted widespread attention from researchers due to their unique advantages in constructing circularly polarized luminescent (CPL) materials with large luminescent asymmetry factor () values. However, how to effectively prepare nondoped CPL chiral liquid crystals remains a challenge. In this article, we developed an effective and universal method to prepare nondoped CPL chiral liquid crystal materials.
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