Jinwook Baek1,Mitesh Mylvaganan1,Yujie Shan1,Huachao Mao1,Sunghwan Lee1
Purdue University1
Jinwook Baek1,Mitesh Mylvaganan1,Yujie Shan1,Huachao Mao1,Sunghwan Lee1
Purdue University1
Recent advances in 3D printing have demonstrated splendid promises in next-generation high performance sensor applications due to freedom of design, cost-effectiveness, and rapid prototyping. In this work, we showcase a new manufacturing paradigm to exclude conventional mold-dependent manufacturing of pressure sensors, which requires a series of complex and expensive patterning processes such as mask aligning, photolithography, and etching. Our mold-free fabrication leverages high resolution 3D printed multiscale microstructures as substrate and a gas-phase conformal polymer coating technique to complete the mold-free sensing platform. Micropatterning through a cutting-edge 3D printer enables one to fabricate a non-trivial structure with complex geometry and customized shapes. The array of dome and spike structures with a controlled spike density was applied for a substrate, ensuring a high surface area. For uniform coating on the microstructured surface, oxidative chemical vapor deposition (oCVD) is leveraged to deposit a highly conformal and conductive electrode, poly(3,4-ethylenedioxythiophene) (PEDOT) at low temperature (< 120 °C). The fabricated pressure sensor reacts sensitively to various ranges of pressures depending on the density of the spike and shows high response (I/I<sub>0</sub> > 10<sup>4</sup>) even pressures under 1 kPa. The mechanism of the high performance achieved was verified through the finite element analysis, which allowed us to identify a correlation between surface structure and sensor characteristics. Our unique findings are expected to be of significant relevance to the technology that requires higher sensing capability, scalability, and facile adjustment of sensor geometry in a cost-effective manufacturing manner.