Niu Li, Miao Xuhong, Li Yutian, Xie Xinkai, Wen Zhen, Jiang Gaoming
Engineering Research Center for Knitting Technology, Ministry of Education, Jiangnan University, Wuxi, China.
School of Textiles and Clothing, Jiangnan University, Wuxi, China.
Nanoscale Res Lett. 2020 Sep 22;15(1):181. doi: 10.1186/s11671-020-03401-1.
Harvesting waste biomechanical energy has provided a promising approach to improve the power supplement of wearable devices for extending usage life. Surface morphology is a significant factor for enhancing output performance of triboelectric nanogenerator; however, there is a limitation for evaluating the morphology of the surface and its impact on power generation. To evaluate the relationship between the surface morphology and transfer charge, there is a mathematical theory that is the fractal geometry theory that has been proposed to analyze the characteristic of irregular surface morphology. This theory provided a good understanding of the contact area and roughness of the surface. We have designed three categories of knit structures with cord appearance by using a flat knitting machine and analyzed their surface characteristics. Meanwhile, the geometric structures can be demonstrated through the fractal dimension for evaluating the generated output performance during contacting and separation. The present research exhibits that, with the increasing number of knitted units, the triboelectric power-generation performance continued to reduce due to the available contact area decreasing. After calculating the fractal dimension of different knit structures, the mn rib structures show the high transfer charge when the fractal dimension is close to number one, especially the fractal dimension of the 11 rib structure that can reach 0.99. The fractal theory can be further used as an approach to evaluate the influence on the output performance of irregular surface morphology, unrelated to the uniform convex unit distraction. The result of this research also demonstrated the feasibility of a knitted-based triboelectric nanogenerator in scavenging biomechanical energy for powering portable electronics integrated into garments.
收集废弃生物机械能为改善可穿戴设备的电力补充以延长使用寿命提供了一种很有前景的方法。表面形态是提高摩擦电纳米发电机输出性能的一个重要因素；然而，在评估表面形态及其对发电的影响方面存在局限性。为了评估表面形态与转移电荷之间的关系，人们提出了一种数学理论——分形几何理论，用于分析不规则表面形态的特征。该理论有助于很好地理解表面的接触面积和粗糙度。我们使用横机设计了三类具有绳状外观的针织结构，并分析了它们的表面特性。同时，可以通过分形维数来展示几何结构，以评估接触和分离过程中产生的输出性能。目前的研究表明，随着针织单元数量的增加，由于可用接触面积减小，摩擦发电性能持续降低。在计算了不同针织结构的分形维数后，当分形维数接近1时，mn罗纹结构显示出高转移电荷，尤其是11罗纹结构的分形维数可达到0.99。分形理论可进一步用作评估不规则表面形态对输出性能影响的一种方法，而与均匀凸单元分散无关。本研究结果还证明了基于针织的摩擦电纳米发电机在收集生物机械能以为集成在服装中的便携式电子设备供电方面的可行性。
