Wearable heater composites comprising traditional Hanji cellulose fibers coated with graphene,silver nanowires,and PEDOT:PSS via scalable supersonic spraying

Traditional Korean Hanji paper and cotton fabric were introduced as flexible substrates in the fabrica-tion of graphene-coated heaters.Silver nanowires and PEDOT:PSS were added to increase the electri-cal conductivity of the heaters,thereby enhancing their heating performance.The optimal concentra-tions of silver nanowires and PEDOT:PSS with respect to that of graphene were identified.These active materials were deposited on flexible Hanji/cotton and non-flexible alumina substrates using supersonic spraying.The proposed Hanji-and cotton-based heaters were light,wearable,stretchable,skin-friendly,and biodegradable.The unyielding alumina-based heater exhibited the highest heating temperature of 275 ℃ at 13 V.Wearable heater bendability and stretchability were tested considering multiple bending and stretching cycles.Moreover,water boiling and fabric drying were successfully performed using the alumina-based heater.The supersonic spraying deposition technique was used to produce writable and patternable heaters.