A Linear Actuation of Polymeric Nanofibrous Bundle for Artificial Muscles

Artificial muscle fiber mimicking myofibril is fabricated using electrospun nanofibers of high strength polyurethane followed by controlled in situ chemical polymerization with aniline. The resulting polyurethane(PU)/polyaniline(PANi) hybrid nanofibrous bundle consisting individual nanofibers of about 900 nm diameter responds to an electrical stimuli producing a linear actuation strain as high as 1.65% at an applied stress of 1.03 MPa in 1 M methane sulfonic acid (MSA), the highest strain produced in the nanofibers templated PANi. The hybrid nanofibrous bundle shows an electrical conductivity of about 0.5 S/cm and the electroactivity is imparted by PANi. The biomimetic artificial nanofibrous bundle shows work per cycle (W.C.) efficiency of above 75% for the electrochemical actuation even beyond 100 cycles. The PU/PANi hybrid nanofibrous bundle could be stably actuated without significant creep up to an applied load of 11 mN (2.263 Mpa) beyond which significant creep behavior appears.