Colorful patterned polyacrylate films prepared using cholesteric liquid-crystalline mixtures with a smectic order

ABSTRACT

Polymer-stabilised cholesteric liquid crystal (PSCLC) films with selective circularly polarised light reflection have attracted much attention for their applications as polarisers, energy-saving windows and for displays. Herein, CLC mixtures were prepared using a nematic LC LC242 and a chiral compound S-6 with enantiotropic SmA and SmC* phases, which exhibited a cholesteric phase with a smectic order. After photopolymerisation, the PSCLC films with fingerprint structure at the surfaces and supramolecular helical structure inside were obtained. Due to the existence of short-range smectic order in the cholesteric structure, the Bragg reflection bands were broadened. For a CLC mixture, with increasing temperature, the short-range smectic order was suppressed, and the selective Bragg reflection band shifted to the short wavelength. Based on this thermochromic behaviour, colourful PSCLC patterns and gratings were prepared, which were able to be applied in decoration and anti-counterfeiting. Since the PSCLC films can be obtained within several seconds under air, large-area films can be prepared on coating lines at low-cost.

GRAPHICAL ABSTRACT

KEYWORDS:

• Liquid crystal
• polyacrylate films
• photopolymerisation
• colourful patterns

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02678292.2023.2182925

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (No. 52273212), Natural Science Foundation of the Jiangsu Higher Education Institutions of China (20KJA430009), the Key Laboratory of Polymeric Materials Design and Synthesis for Biomedical Function and the Project of Scientific and Technologic Infrastructure of Suzhou (SZS201905).