High-performance fibrous artificial muscle based on reversible shape memory UHMWPE

Shape memory polymer fibers (SMPFs) are an important branch of intelligent fibers. Due to their ability to deform under external stimuli, shape memory polymer fibers have been used in intelligent textiles, polymer fillers and medical fields, including surgical sutures, thrombectomy devices, compression stockings, etc. There have been many studies on SMPFs, but almost all reported SMPFs only exhibit a one-way shape memory effect (SME). The deformation process of the one-way SMPFs is irreversible, and the transition from temporary shape to permanent shape cannot be replicated by simply reversing the stimulus. To tackle this problem. We selected ultra-high molecular weight polyethylene (UHMWPE) as the polymer matrix to prepare external stress-free two-way SMPFs. UHMWPE powders are gel-spun and then hot drawn to yield raw UHMWPE fibers. After programming, the UHMWPE fibers possess high tensile strength (338.72 MPa) and Young's modulus (2287.34 MPa), as well as one-way SME, quasi two-way SME and external stress-free reversible two-way SME. The reversible strain of the prepared reversible shape memory UHMWPE fibers is 27.42%. Artificial muscles and actuators can be made from the programmed UHMWPE fibers. The programmed UHMWPE fibers can lift more than 250 times their own weight with ∼10% reversible strain. The programmed UHMWPE fibers are appropriate for industrial mass production since the preparation and programming processes are simple.