Dye-doped Liquid Crystal Elastomers Selectively Actuated By Light Frequenc

Photoactuated liquid crystal elastomer is a kind of polymer intelligent material with light stimulation response performance,which has received extensive attention and scientific research in recent decades because of its advantages of clean and environmentally friendly actuation mode,excellent mechanical properties and designable deformation.However,due to the high phase transition temperature(Tni)of the backbone liquid crystal elastomer material,and the selective actuation of the same liquid crystal elastomer actuator can only be achieved by adjusting the direction of illumination and the position of the light source,this disadvantage greatly limits the application range of complex or sophisticated liquid crystal elastomer actuators.Therefore,we used liquid crystal primitives(RM257)and non-liquid crystal primitives(PEG250)to prepare a series of liquid crystal elastomer materials RM/PEG with different molar ratios RM/PEG(100:0/90:10/80:20)-LCEs respectively to prepare for the actuation of liquid crystal elastomer materials at low temperatures,and at the same time,three organic laser dyes(ABS594,ABS694 and ABS407)were doped with it to obtain dye-doped liquid crystal elastomer materials Dye-407/594/694-RM/PEG(100:0/90:10/80:20)-LCEs,and the relevant characterization and performance tests were carried out on the materials.The main research content and innovation points of this paper are as follows:(1)In this paper,by introducing non-mesogen(PEG250)to replace part of mesogen(RM257),the rigid structure of the main chain type liquid crystal elastomer material(MC-LCE)in the thiol-acylate system was successfully changed,and finally the reduction of sulfur The phase transition temperature(Tni)of the main chain type liquid crystal elastomer material of the alcohol-acrylate system was obtained,and a series of liquid crystal elastomer materials RM/PEG(100:0/90:10/80:20)-LCEs,which is of great significance for actuating liquid crystal elastomer materials at low temperature.(2)In this paper,a series of dye-doped liquid crystal elastomer materials Dye-407/594/694-RM/PEG(100:0/90:10/80:20)-LCEs with different molar ratios of RM/PEG were prepared by solvent exchange technique.,by comparing and analyzing the optical spectrum of the actuated light source,the filtered light after loading the optical filter,the dye molecule and the dye-doped liquid crystal elastomer material,it is proved that the solvent exchange technology successfully solves the problem of photoactuated liquid crystal elastomer preparation.The difficulty in the process is to make the dye molecules evenly distributed inside the liquid crystal elastomer material.(3)In this paper,the photoactuation performance of dye-doped liquid crystal elastomer materials in equal force mode and equal strain mode was tested by general material mechanics analyzer,and the actuation behavior of dye-doped liquid crystal elastomer materials was obvious when the absorption spectrum of the dye coincided with the emission spectrum of the filter light under different filter light irradiation,while the actuation phenomenon of liquid crystal elastomer materials with absorption spectrum beyond the frequency range of filtered light was very weak,which proved that a series of dye-doped liquid crystal elastomer materials had excellent optical frequency selective actuation ability.In summary,a series of dye-doped liquid crystal elastomer materials obtained by two-step crosslinking preparation method and solvent exchange technology have excellent physicochemical properties and optical frequency selective actuation ability,which is of great significance for accurately controlling liquid crystal elastomer actuators using light energy and developing and designing diversified actuators with novel functions.