Transparent and mechanically robust flexible heater based on compositing of Ag nanowires and conductive polymer

A highly flexible and transparent heater was developed from a composite electrode comprising silver nanowires (AgNWs) and a conductive polymer (CP) embedded in a colorless polyimide (cPI) film by a solution-processed inverted layer-by-layer processing method. The resulting CP-AgNW/cPI heater was mechanically stable with increases in resistance of <10% under long-term cyclic bending to a curvature radius of 500 μm for up to 50,000 cycles. A roughness measurement revealed that the high flexibility originated from the electrodes being fully embedded at the surface of the polymer. The fabricated electrode was rapidly heated from room temperature to steady-state temperature within 40 s, with a peak temperature exceeding 200 °C. AgNW hybridization with CP layers was more efficient at lower NW densities, demonstrated by comparisons between the measured and calculated sheet resistance (Rs) of the electrodes. The addition of CP to the existing AgNW electrodes enhanced the steady-state temperature and current-carrying capacity of the fabricated heaters. The results obtained in this study demonstrated that the proposed method of inverted layer-by-layer processing of AgNWs and CP is suitable to achieve a highly reliable and efficient transparent heater.