Bioinspired Cilia Sensors with Graphene Sensing Elements Fabricated Using 3D Printing and Casting
Bioinspired Cilia Sensors with Graphene Sensing Elements Fabricated Using 3D Printing and Casting
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DOI：
10.3390/nano9070954
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发表时间：
2019-07-01
期刊：
影响因子：
5.3
通讯作者：
Kottapalli, Ajay G. P.
中科院分区：
文献类型：
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作者：
Kamat, Amar M.;Pei, Yutao;Kottapalli, Ajay G. P.
在自然界中发现的传感器设计是最佳的，因为它们经过数百万年的进化，使它们非常适合传感应用。然而，使用光刻等传统技术在人工和柔性传感器中复制这些复杂的三维（3D）仿生设计是具有挑战性的。在本文中，我们介绍了一种新的加工范式，用于简化制造具有复杂和仿生结构的柔性传感器。提出的制造工作流程包括3D打印具有复杂3D特征（如微柱和微通道）的金属模具，在模具内浇铸聚二甲基硅氧烷（PDMS）以获得所需结构，并将压阻式石墨烯纳米片滴铸到预先设计的微通道中以形成柔性应变片。石墨烯- pdms应变片通过循环拉伸压缩测试显示，其应变系数高达37。该处理流程被用于制造一种流量传感器，其灵感来自于自然界中发现的毛发状纤毛传感器，该传感器包括一个纤毛启发的支柱和一个带有微通道的悬臂，该悬臂带有石墨烯应变计。该传感器对触觉和水流刺激均表现出良好的灵敏度，前者的检测阈值低至12 μ m，后者的检测阈值低至58 mm/s，证明了我们的方法在开发柔性流量传感器方面的可行性。
Sensor designs found in nature are optimal due to their evolution over millions of years, making them well-suited for sensing applications. However, replicating these complex, three-dimensional (3D), biomimetic designs in artificial and flexible sensors using conventional techniques such as lithography is challenging. In this paper, we introduce a new processing paradigm for the simplified fabrication of flexible sensors featuring complex and bioinspired structures. The proposed fabrication workflow entailed 3D-printing a metallic mold with complex and intricate 3D features such as a micropillar and a microchannel, casting polydimethylsiloxane (PDMS) inside the mold to obtain the desired structure, and drop-casting piezoresistive graphene nanoplatelets into the predesigned microchannel to form a flexible strain gauge. The graphene-on-PDMS strain gauge showed a high gauge factor of 37 as measured via cyclical tension-compression tests. The processing workflow was used to fabricate a flow sensor inspired by hair-like cilia' sensors found in nature, which comprised a cilia-inspired pillar and a cantilever with a microchannel that housed the graphene strain gauge. The sensor showed good sensitivity against both tactile and water flow stimuli, with detection thresholds as low as 12 mu m in the former and 58 mm/s in the latter, demonstrating the feasibility of our method in developing flexible flow sensors.