Light-driven artificial muscles based on electrospun microfiber yarns

Artificial muscles are widely potential in diverse fields including medical treatment, humanoid robotics and industrial automation. Soft materials due to bio-friendly interaction are suitable for those applications. Planar and fiber shape based artificial muscles that use the polymer as substrate materials can be triggered by various stimuli like electric, moisture and heat. Here, artificial muscles based on electrospun microfiber yarns are demonstrated, which can be remotely controlled. The carbon nanotubes embedded in polyurethane microfibers enable the yarns to efficiently absorb near-infrared light and radiate heat, which induces the fast temperature change that leads to the contraction/expansion motions along the axial direction. Microfiber mats are collected by a rotating cylinder that results in highly oriented alignment. The yarns from microfiber mats are highly twisted into the coiled structure, which generates maximum contractive actuation of 6.7% at 70 degrees C. 1000 cycles were demonstrated without an obvious decline of actuating performances. The light-driven artificial muscles can be potentially applied in wireless control, bio-medical devices and so on.