Transparent Sheet Heater with Flexibility based on Poly (vinyl alcohol) Embedded with Sodium Tungstate

Transparent sheet heaters with flexibility (TSHF) exhibiting improved mechanical and thermal stability were made by adding sodium tungstate (NaW) into poly (vinyl alcohol) (PVA) films by solution coating and solvent evaporation method. The prepared TSHFs were characterized by scanning electron microscopy (SEM) to understand the surface morphology better. Further UV-Visible measurement was carried out. The electric conductive properties were assessed by using the four-probe experiment. An infrared thermometer was used to measure the temperature of the TSHFs. The fabricated NaW/PVA hybrid TSHFs demonstrated elevated heating temperatures, 96 °C at a minimum input voltage of 6 V with a minimum response time (T<40 sec), lower power consumption (162 °C cm2 W-1) and process stability after repeated use when compared to ITO/FTO heaters. The bending resistance of the NaW/PVA hybrid TSHFs was excellent. The change in sheet resistance after 1000 cycles of outer bending was less than 18%. The effective embedding of the NaW network in the transparent nascent PVA film's surface reduced surface roughness (Rrms < 1 nm) and improved oxidation and moisture resistance. The produced TSHFs exhibited excellent heating qualities, with their transparency demonstrating remarkable flexibility. The potential uses of NaW/PVA include defogging windows and thermochromic.