Ionic Polymer‐Metal Composite Actuators Employing Radiation‐Grafted Fluoropolymers as Ion‐Exchange Membranes

Abstract

Summary: To develop ionic polymer‐metal composites (IPMC) with improved performance, three new ion‐exchange membranes were prepared and employed in IPMC construction. The membranes were prepared by radiation‐grafting of polystyrene sulfonic acid onto three fluoropolymers; poly(vinylidenefluoride‐co‐hexafluoropropylene), poly(ethylene‐co‐tetrafluoroethylene), and poly(tetrafluoroethylene‐co‐hexafluoropropylene). The bending displacements of the IPMCs constructed with these membranes were at least several times larger than that of Nafion IPMC of similar thickness without straightening‐back. The larger displacement was considered to be due to the higher concentration of ionic groups and consequent larger ion‐exchange capacity.Actuation of (a) Nafion IPMC and (b) IPMC prepared in this study.imageActuation of (a) Nafion IPMC and (b) IPMC prepared in this study.

Radiation‐Grafted Fluoropolymers Soaked with Imidazolium‐Based Ionic Liquids for High‐Performance Ionic Polymer–Metal Composite Actuators

“…[8] The total irradiation dose was varied from 5.0 to 100.0 kGy. Nafion counterpart with a similar thickness (550-700 mm) was prepared by casting of Nafion dispersion (5 wt.-%, DE 521, DuPont) following the procedure described in the literature.…”

Electro‐active Polymer Actuator Based on Sulfonated Polyimide with Highly Conductive Silver Electrodes Via Self‐metallization

“…[17][18][19][20] However, owing to high price, gas permeability and low thermal stability, various alternative polyelectrolyte membranes have been developed. [21][22][23][24] Among recently developed ionic exchange membranes, sulfonated polyimide (SPI), which offers high thermal stability, high proton conductivity, reliable mechanical strength and low price, is of particular interest. Even though a series of SPI polyelectrolytes have been developed for high performance fuel cell membranes, [25,26] so far they have not been used for electro-active polymer actuators.…”

Ionic polymer‐metal composites made from radiation grafted FEP‐g‐styrene‐SO3H membranes

“…9,10,13 Also some studies suggest the use of radiation grafted ion exchange membranes for manufacturing IPMCs. 14 The electrode layer is made by electrochemical plating of noble metals like platinum, gold, silver, palladium etc. 9 The process of electrochemical plating involves two steps: (1) initial compositing process where the metal to be deposited is first allowed to exchange with the membrane and then reduced using a strong reducing agent like sodium borohydride or lithium borohydride; (2) surface electroding process is to grow the metal on top of the initial coated layer to reduce the surface resistance.…”