Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2019 Aug 27;10(1):3862. doi: 10.1038/s41467-019-11803-8.
Current metal film-based electronics, while sensitive to external stretching, typically fail via uncontrolled cracking under a relatively small strain (~30%), which restricts their practical applications. To address this, here we report a design approach inspired by the stereocilia bundles of a cochlea that uses a hierarchical assembly of interfacial nanowires to retard penetrating cracking. This structured surface outperforms its flat counterparts in stretchability (130% versus 30% tolerable strain) and maintains high sensitivity (minimum detection of 0.005% strain) in response to external stimuli such as sounds and mechanical forces. The enlarged stretchability is attributed to the two-stage cracking process induced by the synergy of micro-voids and nano-voids. In-situ observation confirms that at low strains micro-voids between nanowire clusters guide the process of crack growth, whereas at large strains new cracks are randomly initiated from nano-voids among individual nanowires.
目前基于金属薄膜的电子产品虽然对外界拉伸敏感，但通常会在相对较小的应变（~30%）下发生不受控制的开裂，从而限制了它们的实际应用。针对这一问题，我们受到耳蜗内细胞纤毛束的启发，提出了一种设计方法，通过界面纳米线的分级组装来延缓穿透性裂纹的扩展。这种结构化表面在拉伸性能方面优于其平面对应物（可承受的应变分别为 130%和 30%），并且在响应声音和机械力等外部刺激时保持高灵敏度（最小检测应变低至 0.005%）。这种可拉伸性的提高归因于微空隙和纳米空隙协同作用引起的两阶段裂纹扩展过程。原位观察证实，在低应变下，纳米线簇之间的微空隙引导裂纹生长过程，而在大应变下，新的裂纹会从单个纳米线之间的纳米空隙中随机产生。
