A Hollow Polyethylene Fiber-Based Artificial Muscle

Recently, researches on artificial muscles for imitating the functions of the natural muscles has attracted wide attention. The fiber-shape actuators, shape-memory materials or deforming devices, which are similar to human muscle fiber bundles, have extensively studied and provided more possibilities for artificial muscles. Herein, we develop a thermal responsible fiber-shaped actuator based on the low-cost hollow polyethylene fiber. The sheath-core structured fibrous actuators and the stainless-steel conductive yarn winded pre-stretched polyethylene actuators are fabricated with the heating assisted pre-stretching procedure. The actuation mechanism of the thermal-responsive orientation change of molecular chains driving the actuation is discussed and demonstrated by 2D XRD patterns. These polyethylene-based fibrous actuators displayed three significant advantages including (i) color-turning and shape-changing bifunctional response, (ii) direct joule heating actuation and (iii) effective contraction (18% shrinkage of the pristine length) and lifting ability (the ratio of lifting weight to self-weight is up to 50).