He Qingsong

Effect of surface roughening method onperformance of IPMC artificial muscle

Ionic Polymer Metal Composite (IPMC) is a new kind of ionic Electro-active nPolymer (EAP) composed of a perfluorinated polymer membrane coated nwith a noble metal (usually use Pt and Au) on both sides, which behaves nlike biological muscle bends towards the anode (in the case of cation nexchange membrane) under the influence of an applied electric field. nSince it has several advantages such as large deformation, light weight, nflexibility, bio-compatibility and low driving voltage compared with nshape memory alloy materials and piezoelectric ceramic, IPMC, also ntermed “artificial muscle”, can be widely applied to nthe actuators, sensors, biomimetic materials and medical engineering. nAs a kind of composite materials composed of polymer and metal, the nperformance of IPMC is closely related to the construction between npolymer membrane and metal electrode. Surfaces roughening treatment nof the Nafion membranes is employed in order to improve the construction nway of the interfaces between polymer membranes and metal electrodes, nwhich is a significant method to improve the electromechanical properties nof IPMC materials. In this paper, a controllable and directional surface ntreatment for IPMC was developed. A surface roughening device included nfriction head, membrane jig and fixed stage was demonstrated for the nIPMC membranes based on linear reciprocating motion of the UMT-2 friction-abrasion ntesting machine. Compared with manual surfaces roughening treatment, nmechanical surface roughening treatments under 20, 50 and 80 N three nkinds of load was used. The same preparation process was guaranteed nto prepare IPMC on the basis of Nafion membranes with different surfaces nroughening methods. The surface morphology of the Nafion membranes nwas observed using digital microscope. The cross-sectional and metal nelectrodes of the IPMC were observed using scanning electron microscopy n(SEM). The surface roughness of the roughened membranes were measured nwith surface profiler. The effect of different roughening treatments nmethods and loading condition on the displacement and blocking force nof IPMC artificial muscle were investigated using home-built apparatus. nCompared with IPMC with manual surfaces roughening treatment, the nIPMC with 20 N roughening load shows the best actuation performance nof displacement, and the IPMC with 50 N roughening load shows the nbest actuation performance of blocking force. Mechanical roughening nmethod can exclude the human factors in the manual roughening process, nand produce controllable loading strength and direction, making the npolishing cracks uniform in depths and directions. Compared with manual nsurfaces roughening treatment, the compactness constructed of the ninterfaces between polymer membranes and metal electrodes can be improved nby the mechanical surface roughening treatments, the adsorption capability nand deposition thickness of the Pt particles were increased. Thus, nthe flat and dense electrode with uniform cracks was obtained, which ndefinitely reduced the surface resistance and enhance the blocking nforce and displacement of IPMC. The denser and thicker electrodes ncan prevent water leakage and extend the effective operating time nof IPMC artificial muscle in the air. This research can improve the nstability of the preparation process, which lays a solid foundation nfor the standardization of preparation process of IPMC. Also, the nactuation performance of IPMC was enhanced, guaranteeing the further ndevelopment and application of IPMC artificial muscle.