Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea.
Department of Mechanical Engineering, Ajou University, San 5, Woncheon-dong, Yeongtong-gu, Suwon 443-749, Republic of Korea.
Sci Rep. 2017 Jan 6;7:40116. doi: 10.1038/srep40116.
Recently, a mechanical crack-based strain sensor with high sensitivity was proposed by producing free cracks via bending metal coated film with a known curvature. To further enhance sensitivity and controllability, a guided crack formation is needed. Herein, we demonstrate such a ultra-sensitive sensor based on the guided formation of straight mechanical cracks. The sensor has patterned holes on the surface of the device, which concentrate the stress near patterned holes leading to generate uniform cracks connecting the holes throughout the surface. We found that such a guided straight crack formation resulted in an exponential dependence of the resistance against the strain, overriding known linear or power law dependences. Consequently, the sensors are highly sensitive to pressure (with a sensitivity of over 1 × 10 at pressures of 8-9.5 kPa range) as well as strain (with a gauge factor of over 2 × 10 at strains of 0-10% range). A new theoretical model for the guided crack system has been suggested to be in a good agreement with experiments. Durability and reproducibility have been also confirmed.
最近，通过弯曲具有已知曲率的金属涂层膜来产生自由裂纹，提出了一种基于机械裂纹的高灵敏度应变传感器。为了进一步提高灵敏度和可控性，需要进行引导裂纹形成。在此，我们展示了一种基于直机械裂纹引导形成的超灵敏传感器。该传感器在器件表面有图案化的孔，这些孔集中了附近的应力，导致在整个表面上产生均匀的连接孔的裂纹。我们发现，这种引导直裂纹的形成导致电阻对应变的依赖呈指数关系，超过了已知的线性或幂律关系。因此，这些传感器对压力（在 8-9.5 kPa 的压力范围内的灵敏度超过 1×10）和应变（在 0-10%的应变范围内的应变系数超过 2×10）都非常敏感。提出了一种新的引导裂纹系统理论模型，与实验结果吻合较好。还确认了耐用性和可重复性。
