Photo‐Crosslinked Side‐Chain Liquid‐Crystalline Elastomers for Microsystems

Abstract

Photo‐crosslinkable side‐chain liquid‐crystalline polymers (LCPs) containing photoreactive benzophenone cores are synthesized in order to obtain their corresponding side‐chain liquid‐crystalline elastomers (LCEs). This strategic synthesis allows thin elastomeric films and their integration into microsystems for actuators and micromachines to be obtained. As an example of this principle, a gripper was developed. The position of its arms can be changed by applying voltages from 1.5 to 3.5 V at different rates. Small changes in the liquid‐crystalline elastomer film cause strains of up to 150% in the microdevice and the capacity to move up to 400 times its own mass due to the nematic‐to‐isotropic transformation.magnified image

Nanoparticle-Liquid Crystalline Elastomer Composites

“…Of these, liquid crystal elastomers (LCEs) are a particularly useful and interesting class of materials that combine softness, elasticity, durability, light weight, high force density, and notable mechanical strength with dramatic reversible actuation [3]. They have been studied as valuable candidates for artificial muscles for some time, and they also exhibit interesting potential as motors [4,5], contact lenses [6], microgrippers in microsystems [7], valves for microfludics [8] and tunable lasing media [9][10][11][12][13].…”

Study of the optical, thermal, and mechanical properties of nematic liquid crystal elastomers

“…Another interesting and unusual property of LCE is that its physical behavior can be controlled by various external stimuli, such as heat, light, electric field, and mechanical stress [18,19]. These exceptional properties of LCE have led to its widespread application in artificial muscles [20][21][22], shape memory [23][24][25][26][27], thermomechanical actuation [2,7,8,28], soft elasticity [29][30][31][32], motors [22,23], contact lenses [24], micro-grippers in microsystems [25], valves for microfluids [26], tunable lasing media [28][29][30][31][32], electro-optical systems like adaptive lenses [24,33], and sensors [9,10,34].…”

Opto‐Mechanical Effect in Photoactive Nematic Side‐Chain Liquid‐Crystalline Elastomers

“…[7][8][9][10] Such materials have a variety of potential uses, as switchers, actuators, or artificial muscles (sensor or movement actuator). [11][12][13][14][15][16][17] We are interested in investigating the response of nematic SCLCEs that contain azoderivatives [18,19] as pendant co-monomers [9,20] or crosslinkers [7,10] in order to establish the effect of their architecture when an external field (heat or light) is applied. Under irradiation, the change in shape of these azoderivatives, from the rod-like shape (trans-isomer) to the bended-like shape (cis-isomer), leads to a local disorder in the sample that is related to a change in the dimensions of the elastomer.…”