Flexible biodegradable transparent heaters based on fractal-like leaf skeletons  

作　　者：Vipul Sharma Anastasia Koivikko Kyriacos Yiannacou Kimmo Lahtonen Veikko Sariola 

机构地区：[1]Faculty of Medicine and Health Technology,Tampere University,Finland Korkeakoulunkatu 3,33720,Tampere,Finland [2]Faculty of Engineering and Natural Sciences,Tampere University,P.O.Box 692,33014,Tampere,Finland

出　　处：《npj Flexible Electronics》2020年第1期235-242,共8页npj-柔性电子（英文）

基　　金：This work was supported by the Academy of Finland(Grants:#299087 and#292477).

摘　　要：We present a facile method to prepare flexible,transparent,biodegradable,and fast resistive heaters by applying silver(Ag)nanowires onto fractal-like leaf skeletons.The fractal-like structure of the leaf skeleton maximizes its surface area,improving the transfer of heat to its surroundings and thus making the heater fast,without compromising transparency.Ag ion layer on the leaf skeleton helps to conformally cover the surface with Ag nanowires.The sheet resistance of the heater can be controlled by the loading of Ag nanowires,without sacrificing the optical transmittance(~80%at 8Ωsq^(−1)).The heating is uniform and the surface temperature of a 60 mm×60 mm heater(8Ωsq^(−1))can quickly(5-10 s)raise to 125℃ with a low voltage(6 V).The heater displays excellent mechanical flexibility,showing no significant change in resistance and heating temperature when bent up to curvature of 800 m^(−1).Finally,we demonstrate the potential of the bioinspired heater as a thermotherapy patch by encapsulating it in a biodegradable tape and mounting it on the human wrist and elbow.This study shows that fractal-like structures from nature can be repurposed as fractal designs for flexible electronics.

关 键 词：NANOWIRES fractal TRANSPARENT 

分 类 号：TB3[一般工业技术—材料科学与工程]