Fabrication of a Printed Heater Using a Composite of Silver Nanowires and Neutral PEDOT:PSS

In this work, a low-resistance heater based on a composite of silver nanowires (Ag NWs) and neutral poly(3,4-ethylenedioxythiophene) poly(styrene sulphonate) (PEDOT:PSS) is fabricated. Pure Ag NWs have poor substrate adhesion, poor environmental and thermal stability, and high surface roughness. Local hotspots at wire junctions also lead to uneven Joule heating. These disadvantages are overcome by blending the NWs with PEDOT:PSS. Specifically, neutral PEDOT:PSS is used in this work, as it is less hygroscopic and possesses greater environmental stability compared with the conventionally used acidic PEDOT:PSS. The composite is synthesized as a stable printable dispersion and deposited on a flexible polyethylene terephthalate (PET) substrate using an extrusion-based direct write system. Film thickness was optimized to achieve low sheet resistance and good adhesion, and it is laminated with polydimethylsiloxane (PDMS) for environmental protection. The heater shows uniform temperature distribution with a short response time and low operating voltage. Temperature distribution modeling was carried out using COMSOL Multiphysics software and correlated well with the experimental data. The heater also exhibits good repeatability and cyclic thermal stability. A prototype device with temperature cutoff and feedback was also implemented using an Arduino controller.