The robust and reliable mechanical characteristics of metal nanoparticle (NP) thin films on flexible substrates are important because they operate under tensile, bending, and twisting loads. Furthermore, in wearable printed electronics applications, salty solutions such as sweat and seawater can affect the mechanical reliabilities of devices. In this paper, we investigated the effect of sodium chloride (NaCl) solutions on silver (Ag) NP thin films on flexible polymer substrate. After exposure to NaCl solution of Ag NP thin film, we observed the aggregation behavior between Ag NPs and formation of larger pores in the film due to the removal of organic capping layer from the surface of Ag NPs. The average porosity and 5% deviation strains of Ag NP thin films on the PI substrate were dramatically increased and decreased from 2.99% to 9.64% and from 3.94% to 0.87%, respectively, after exposure to NaCl solution for 1 h. Also, we verified a drastic deterioration of the surface adhesion of the Ag NP thin film to the substrate by exposure to NaCl solution. We could observe crack propagation and delamination by in-situ SEM imaging. In addition, passivation effect by a parylene layer for preventing the permeation of the saline solution was investigated.

中文翻译：

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暴露于盐溶液的柔性基板上金属纳米颗粒薄膜的力学特性

金属纳米颗粒 (NP) 薄膜在柔性基板上的稳健可靠的机械特性非常重要，因为它们在拉伸、弯曲和扭转载荷下工作。此外，在可穿戴印刷电子应用中，汗液和海水等含盐溶液会影响设备的机械可靠性。在本文中，我们研究了氯化钠 (NaCl) 溶液对柔性聚合物基板上的银 (Ag) NP 薄膜的影响。在暴露于 Ag NP 薄膜的 NaCl 溶液后，我们观察到 Ag NPs 之间的聚集行为以及由于从 Ag NPs 表面去除有机覆盖层而在薄膜中形成较大孔。PI基板上Ag NP薄膜的平均孔隙率和5%偏差应变显着增加，从2.99%下降到9.64%，从3下降到3。暴露于 NaCl 溶液 1 小时后，分别为 94% 至 0.87%。此外，我们通过暴露于 NaCl 溶液验证了 Ag NP 薄膜对基板的表面粘附性急剧恶化。我们可以通过原位 SEM 成像观察裂纹扩展和分层。此外，研究了聚对二甲苯层的钝化效果以防止盐水溶液的渗透。