Scalable Forming and Flash Light Sintering of Polymer-Supported Interconnects for Surface-Conformal Electronics
Scalable Forming and Flash Light Sintering of Polymer-Supported Interconnects for Surface-Conformal Electronics
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DOI：
10.1115/1.4042610
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发表时间：
2019-04
期刊：
影响因子：
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通讯作者：
H. Devaraj;R. Malhotra
中科院分区：
文献类型：
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作者：
H. Devaraj;R. Malhotra
将导电电路与刚性3D表面共形集成是智能材料和结构的关键需求。本文研究了连续热成型和闪光烧结（FLS）的导电银（Ag）纳米线（NW）的平面聚合物片材上印刷的互连。因此，所得的互连聚合物组件被预成形为所需的3D几何形状，并且可以牢固地附接到表面。这种保形电路集成方法避免了平面柔性电子器件的手动构造中的互连分层，消除了直接保形印刷中3D物体的加热，并且使得能够容易地更换电路。热成型后的互连电阻增加，但关键的是，通过随后的FLS显着降低。电阻与成形应变、互连线厚度和FLS能量密度呈非线性关系。这些观察背后的基本物理是通过了解互连形态和温度演变过程中发现的。在这里找到的最佳参数下，该工艺在1平方英寸的形成面积上以100%最大应变在90.8 s内实现<10 Ω/cm的互连电阻。通过一个简单的共形LED照明电路证明了这个过程中的复杂表面的应用。这种方法的潜力，使表面尺寸和材料的不敏感性，鲁棒的集成，并易于替换共形电路制造进行了讨论。
Conformally integrating conductive circuits with rigid 3D surfaces is a key need for smart materials and structures. This paper investigates sequential thermoforming and flash light sintering (FLS) of conductive silver (Ag) nanowire (NW) interconnects printed on planar polymer sheets. The resulting interconnect–polymer assemblies are thus preshaped to the desired 3D geometry and can be robustly attached to the surface. This conformal circuit integration approach avoids interconnect delamination in manual conformation of planar flexible electronics, eliminates heating of the 3D object in direct conformal printing, and enables easy circuit replacement. The interconnect resistance increases after thermoforming, but critically, is reduced significantly by subsequent FLS. The resistance depends nonlinearly on the forming strain, interconnect thickness, and FLS fluence. The underlying physics behind these observations are uncovered by understanding interconnect morphology and temperature evolution during the process. With the optimal parameters found here, this process achieves interconnect resistance of <10 Ω/cm within 90.8 s at 100% maximum strain over a 1 square inch forming area. The application of this process for complex surfaces is demonstrated via a simple conformal LED-lighting circuit. The potential of this approach to enable surface size and material insensitivity, robust integration, and easy replaceability for conformal circuit fabrication is discussed.