Analysis of a Hybrid Micro-Electro-Mechanical Sensor Based on Graphene Oxide/Polyvinyl Alcohol for Humidity Measurements

Abstract

In this paper, we present a redundant microsensor based on the bulk and etch silicononinsulator (BESOI) process for measuring relative humidity (RH), by using a grapheneoxide/polyvinylalcohol (GO/PVA) composite. The MEMS is a mechanical oscillator, composed of a proof mass with multilayer of nanomaterials (GO/PVA) and suspended by four crab-leg springs. The redundant approach realized concerns the use of different readout strategies in order to estimate the same measurand RH. This is an intriguing solution to realize a robust measurement system with multiple outputs, by using the GO/PVA as functional material. In the presence of RH variation, GO/PVA (1) changes its mass, and as consequence, a variation of the natural frequency of the integrated oscillator can be observed; and (2) varies its conductivity, which can be measured by using two integrated electrodes. The sensor was designed, analyzed and modeled; experimental results are reported here to demonstrate the effectiveness of our implementation.

Toward Humidity-Independent Sensitive and Fast Response Temperature Sensors Based on Reduced Graphene Oxide/Poly(vinyl alcohol) Nanocomposites

“…The resulting temperature sensitivity was due to fiber temperature dependence. 24 The use of GO/PVA as a humidity sensor in a redundant measurement approach with a micro-electromechanical system (MEMS) oscillator was demonstrated by employing the variation of its conductivity and mass, resulting in a change of the resonance frequency of the oscillator 25 To the best of our knowledge, there are only very few publications on temperature sensors based on GO/PVA composites. Temperature sensitivity was observed in a GO/PVA hydrogel flexible strain/pressure sensor 26 with high sensitivity and a temperature coefficient of resistance (TCR) of 3.5%.…”