3D打印聚氨酯微流道封装镓基液态金属柔性导线及其性能

Fabrication and Properties of Flexible Gallium-based Liquid Metal WiresEncapsulated in 3D Printed Polyurethane Microchannel

利用3D打印制备了聚氨酯(TPU)微流道,并采用注射器将GaInSn液态金属注入后封装,得到液态金属柔性导线。采用扫描电子显微镜(SEM)和能谱分析仪(EDS)对液态金属的形貌及结构进行表征。利用万用表和电化学工作站分别测试了复杂流道中的液态金属及外力作用下不同尺寸柔性导线的导电性能,并通过对比商用柔性电路板(FPC),测试了柔性导线在反复弯曲及对折下的抗疲劳性。结果表明,该液态金属由67.2%Ga、20.1%In和12.7%Sn(均为质量分数)组成,将其与TPU柔性材料结合,可制备多层复杂的结构电路;在压力(0~190 N)和弯曲变形(0~360°)的外力作用下,外力对液态金属柔性导线的导通性能基本无影响,其中,微流道横截尺寸为0.5 mm×0.5 mm时,外力对其影响最小;对比商用FPC,液态金属柔性导线在循环弯曲24 h、对折压实200次的条件下仍未发生断裂,其电阻仅增加0.02Ω,展现了液态金属在复杂柔性电路制造领域的巨大应用潜力。

Flexible liquid metal wires were fabricated by the injection and encapsulation of GaInSn liquid metal TPU into flexible polyurethane microchannels fabricated by 3D printing.Morphology and composition of GaInSn liquid metal were characterized by scanning electron microscopy(SEM)and energy dispersive X-ray spectroscopy(EDS).A multimeter and an electrochemical workstation were used to test the conductive properties of flexible wires of different sizes under the action of the liquid metal in the complex flow channel and external forces,and compared with commercial FPCs to test the fatigue resistance of the flexible wires under repeated bending and double folding.The results show that the liquid metal is composed of 67.2%Ga,20.1%In and 12.7%Sn by mass.It can be combined with TPU flexible material to prepare a multilayer complex structure circuit;under pressure(0—190 N)and bending deformation(0—360°),the external force has basically no effect on the conduction performance of the liquid metal flexible wire.Among them,when the cross-sectional dimension of the micro-channel is 0.5 mm×0.5 mm,the external force has the least influence on it;compared with commercial FPC,the metal flexible wire did not break under the condition of cyclic bending for 24 hours and double folding and compacting 200 times,and its resistance increased by only 0.02Ω;it showed the huge application potential of liquid metal in the field of complex flexible circuit manufacturing.