Mold‐Free Manufacturing of Highly Sensitive and Fast‐Response Pressure Sensors Through High‐Resolution 3D Printing and Conformal Oxidative Chemical Vapor Deposition Polymers

Abstract

AbstractA new manufacturing paradigm is showcased to exclude conventional mold‐dependent manufacturing of pressure sensors, which typically requires a series of complex and expensive patterning processes. This mold‐free manufacturing leverages high‐resolution 3D‐printed multiscale microstructures as the substrate and a gas‐phase conformal polymer coating technique to complete the mold‐free sensing platform. The array of dome and spike structures with a controlled spike density of a 3D‐printed substrate ensures a large contact surface with pressures applied and extended linearity in a wider pressure range. For uniform coating of sensing elements on the microstructured surface, oxidative chemical vapor deposition is employed to deposit a highly conformal and conductive sensing element, poly(3,4‐ethylenedioxythiophene) at low temperatures (<60 °C). The fabricated pressure sensor reacts sensitively to various ranges of pressures (up to 185 kPa−1) depending on the density of the multiscale features and shows an ultrafast response time (≈36 µs). The mechanism investigations through the finite element analysis identify the effect of the multiscale structure on the figure‐of‐merit sensing performance. These unique findings are expected to be of significant relevance to technology that requires higher sensing capability, scalability, and facile adjustment of a sensor geometry in a cost‐effective manufacturing manner.