Facile fabrication of patternable and large-area elastic liquid crystal polymer films

ABSTRACT

Cholesteric liquid crystal elastomers (CLCEs) can change structural colour in response to mechanical stimuli, which can be applied as sensors and optical devices. Thus, the facile fabrication of large-area CLCE films is critical but challenging. Herein, a simple procedure for the preparation of CLCE films by adding a chain-transfer agent is reported. When the CLCE films are fixed between two thermoplastic polyurethane (TPU) films, the obtained TPU/CLCE/TPU sandwich films exhibit mechanochromic behaviours. Due to the decrease of the helical pitch of CLCE film upon stretching, the selective Bragg reflection band shifts to short wavelength. Based on this structural colour change, a flower pattern can emerge or vanish upon stretching. Moreover, a two-dimensional tetragonal grating with elasticity is prepared. The TPU/CLCE/TPU films can be facilely fabricated over large area and used as car films.

GRAPHICAL ABSTRACT

KEYWORDS:

• Cholesteric liquid crystal elastomers
• structural colour
• mechanochromic behaviour
• two-dimensional tetragonal grating
• car films

Disclosure statement

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

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02678292.2023.2200266.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [52273212], the 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].