Inkjet-printed heater on flexible substrates for low voltage applications

Abstract

Abstract Flexible heaters have applications ranging from defoggers to flexural warmers, food processors, and thermotherapy. Printed flexible heaters are particularly of interest as they offer unique advantages like high resolution, customization, low cost, and ease of fabrication. Here, we report printed flexible heaters on polyethylene terephthalate (PET) substrate. The heater design is optimized to operate on a low voltage of five volts and yield high temperatures with a uniform temperature distribution across the surface. The heater has a fast response time of 15 seconds to reach its maximum temperature and does not show any degradation in performance after three months of operation. The heater maintains its temperature after continuous use for two hours and exhibits a minimum change in temperature upon bending. We have also developed and tested designs for zone heaters and nano heaters, where zone heater is suited for applications requiring heating in specified locations on a surface only. Whereas nano heater has an area of 1 mm2 and can produce high temperatures in this small area. Finally, we developed similar printed heaters on paper and polyimide substrates as well. Paper-based heater can achieve a temperature of 210 °C and can be used in disposable applications due to its low cost, whereas polyimide heater can achieve a temperature of 380 °C and is suitable for attaining high temperatures. These results manifest the use of flexible heaters for various practical applications.