Photothermal porous monodomain liquid crystal elastomer actuator based on confined expansion method

Abstract

Light-driven monodomain liquid crystal elastomers (mLCEs) have the advantages of remote operation and local control, but the response time will increase rapidly with the increase of thickness due to the limitation of the incident light depth. In order to achieve fast response, porous AuNPs-mLCEs actuators are proposed and fabricated by a confined expansion method. The average pore size of the prepared rod-shaped porous mLCEs is 200 μm, the porosity is 46.5%, and the order parameter of mesogens is 0.41. When the diameter is 3 mm, the response time is 1.2 s at a wavelength of 532 nm and a light intensity of 2.6 W•cm−2. When the diameter increases to 10 mm, the response time only increases to 2.2 s. The contraction of porous mLCEs actuator caused by the photothermal effect enables it can not only to lift an object 321.5 times heavier than itself by contraction, but also raise-up an object 5.2 times heavier than itself by bending. This method can be used to design and manufacture various 3D porous photothermal actuators with fast response.