Preparation and characterisation of liquid crystal elastomer films with selective reflectivity

ABSTRACT

In this paper, the liquid crystal elastomer films (A’BG series) have been prepared by grafting polymerisation, using the 4-allyloxybenzoic acid cholesteryl ester (M_B) as liquid crystal monomer, dodecane-1,12-diyl bis(undec-10-enoate) (M_G) as flexible cross-linker and polymethyl hydrosiloxane (containing 35 Si-H) as the main chain. The A’BG series films are cholesteric liquid crystal elastomer films (LCEs) with a liquid crystal region above 100°C. With the crosslinker content decreasing, A’BG-2 and A’BG-3 display selective reflection in UV region and visible region, respectively. The selective reflection wavelength of A’BG-3 occurs blue shift with the temperature increasing. The glass transition temperatures (T_g) of the A’BG series films are 16.4–40.8°C and A’BG series films display shape memory properties near room temperature. The A’BG series elastomer films have a high thermal stability and the temperatures of the 5% mass loss are above 300°C. The backbone siloxane structures in the A’BG series elastomer films are highly stable, and the -COOChol group is relatively easy to decompose.

GRAPHICAL ABSTRACT

KEYWORDS:

• Liquid crystal
• elastomer film
• cholesteric phase
• selective reflectivity

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/10.1080/02678292.2023.2173814.

Additional information

Funding

This work is supported by “the Fundamental Research Funds for the Central Universities” (N2224001) and supported by National Training Program of Innovation and Entrepreneurship for Undergraduates (Project S202210145086).