Suppressing the negative temperature coefficient effect of resistance in polymer composites with positive temperature coefficients of resistance by coating with parylene†
One of the problems of polymer thermistors with a positive temperature coefficient (PTC) is a negative temperature coefficient (NTC) effect. This study proposes a parylene coating on thermistors to suppress the NTC effect while maintaining the PTC characteristics. An 800 nm-thick parylene coating suppressed the NTC effect to 11.8%. Electrical impedance spectroscopy revealed that the parylene coating prevented the formation of new conductive paths, which led to the elimination of the NTC effect.