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Polymer Nanocomposite in Flexible Electronics Packaging



Commercial electronic products are not specifically designed to perform in extremely transient high impact scenarios. Future electronic device packagings to perform in high impact scenarios need to exhibit and meet electrical performance along with mechanical flexibility. The new materials in this study consist of an elastomeric matrix with nano constituents forming a percolated electrically conductive network and therefore exhibit very high electrical conductivity, flexibility, and shock absorption. For electrically conductive and strain-resilient materials, Ag-CB (silver-carbon black)/thermosetting epoxy polymer and Ag- CB/thermoplastic polyurethane composites were developed. Excellent electrical conductivity could be achieved for these nanocomposites. The morphology of the nanocomposite was investigated by transmission electron microscopy (TEM), indicating that the Ag-coated carbon blacks and/or silver nanoparticles were wellconnected to form the network; resulting in excellent electrical conductivity of the nanocomposite. Split Hopkinson Pressure Bar (SHPB) test of the Ag-CB/epoxy nanocomposite showed that this material exhibited excellent durability and small changes in electrical conductivity, indicating this material could be promising to be used as the solder material in flexible electronics. These nanocomposite materials were also successfully used to print flexible circuits using a 3D-printing. The electrical resistance change under tensile strain for the Ag-CB/TPU nanocomposite printing as a trace on polyethylene terephthalate (PET) showed a small increase of ΔR/R0 until 40% strain. Simultaneously, there are almost no changes of the electrical resistance after the bending cycles (fatigue test) for Ag-CB/TPU on PET. So it is promising for these highly conductive polymer nanocomposites to be used as an alternative solution for electronic materials needed to perform in extremely transient high impact scenarios.

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