Manufacturing conformal electrically conductive circuits on rigid freeform surfaces currently require compromises between process scalability, cost, and thermal tolerance and geometric complexity of the object material. The Form-Fuse process operates by printing silver nanoparticle interconnects on planar polymer sheets followed by sequential vacuum forming and Flash Light Sintering (FLS) and can overcome the above issues. We investigate the role of nanoparticle morphology on this process by using nanowires (NW) in combination with nanoflakes (NF) and nanospheres (NS) as the printed nanoparticles. The characterization of FLS temperature, electrical resistance, morphology, and optical absorption along with electromagnetic and molecular dynamics modeling yields the following insights. The forming-induced resistivity rise is greater for higher NS and NF content due to localized embedding of NWs into the polymer. This embedding also reduces blowoff defects during FLS to create an expanded defect-free FLS window. The resistance reduction due to FLS is also greater for the mixed NW-NF and NW-NS cases, thanks to the change in localized optical absorption and interparticle fusion kinetics upon the introduction of NFs and NSs into a NW ensemble. The change in fusion kinetics is driven by enhanced dislocation growth between nanoparticles, despite surface and grain boundary diffusion trends contrary to the neck growth trends. We show that Form-Fuse can achieve similar or lesser electrical resistivity than state-of-the-art conformal 3D printing while enabling greater scalability and structural material capability and retaining the capability to handle complex shapes. We discuss the impact of our findings on the nanoparticle material cost and capabilities of Form-Fuse compared to other conformal electronics manufacturing processes.

目前，在刚性自由曲面上制造共形导电电路需要在过程可扩展性，成本，热容忍度和目标材料的几何复杂度之间折衷。Form-Fuse工艺通过在平面聚合物片材上印刷银纳米粒子互连，然后依次进行真空成型和Flash Sintering（FLS）进行操作，可以克服上述问题。我们通过使用纳米线（NW）结合纳米薄片（NF）和纳米球（NS）作为印刷纳米颗粒，研究了纳米颗粒形态在此过程中的作用。FLS温度，电阻，形态和光学吸收的表征以及电磁和分子动力学建模得出以下见解。由于NWs局部嵌入聚合物中，对于较高的NS和NF含量，形成诱导的电阻率升高更大。这种嵌入还减少了FLS期间的吹扫缺陷，从而创建了扩展的无缺陷FLS窗口。在混合NW-NF和NW-NS情况下，由于FLS引起的电阻降低也更大，这归功于将NFs和NSs引入NW整体后局部光吸收和粒子间融合动力学的变化。尽管表面和晶界扩散趋势与颈部生长趋势相反，但纳米颗粒之间位错生长的增强驱动了熔合动力学的变化。我们证明，Form-Fuse可以实现比最新的保形3D打印相似或更低的电阻率，同时具有更大的可扩展性和结构材料能力，并保留处理复杂形状的能力。与其他共形电子制造工艺相比，我们讨论了我们的发现对纳米颗粒材料成本和Form-Fuse功能的影响。