Facile Fabrication of Conductive Graphene/Polyurethane Foam Composite and Its Application on Flexible Piezo-Resistive Sensors

Abstract

Flexible pressure sensors have attracted tremendous research interests due to their wide applications in wearable electronics and smart robots. The easy-to-obtain fabrication and stable signal output are meaningful for the practical application of flexible pressure sensors. The graphene/polyurethane foam composites are prepared to develop a convenient method for piezo-resistive devices with simple structure and outstanding sensing performance. Graphene oxide was prepared through the modified Hummers method. Polyurethane foam was kept to soak in the obtained graphene oxide aqueous solution and then dried. After that, reduced graphene oxide/polyurethane composite foam has been fabricated under air phase reduction by hydrazine hydrate vapor. The chemical components and micro morphologies of the prepared samples have been observed by using FT-IR and scanning electron microscopy (SEM). The results predicted that the graphene is tightly adhered to the bare surface of the pores. The pressure sensing performance has been also evaluated by measuring the sensitivity, durability, and response time. The results indicate that the value of sensitivity under the range of 0–6 kPa and 6–25 kPa are 0.17 kPa−1 and 0.005 kPa−1, respectively. Cycling stability test has been performed 30 times under three varying pressures. The signal output just exhibits slight fluctuations, which represents the good cycling stability of the pressure sensor. At the same stage, the response time of loading and unloading of 20 g weight turned out to be about 300 ms. These consequences showed the superiority of graphene/polyurethane composite foam while applied in piezo-resistive devices including wide sensitive pressure range, high sensitivity, outstanding durability, and fast response.

A Green Approach to Modify Surface Properties of Polyurethane Foam for Enhanced Oil Absorption

“…We can see that the PU/PHFBA i foam exhibits a relatively smoother surface compared to the control PU foam when both samples are examined under higher magnification (×20,000). The small white dots on the surface of the control foam are the protrusions that are naturally found in PU foam [ 26 , 27 ]. The changes in the surface morphology can indicate the impact of CVD modification on the surface properties of foam at the nm level.…”

Linearly Sensitive and Flexible Pressure Sensor Based on Porous Carbon Nanotube/Polydimethylsiloxane Composite Structure

“…To fulfill these requirements, polymer-based flexible sensors have been investigated. Previous studies have reported polymer-based flexible sensors utilizing piezoresistive [9][10][11][12][13], capacitive [14][15][16][17], piezoelectric [18,19], and triboelectric sensing technologies [20,21]. Among these, piezoresistive devices, which transduce pressure into a resistance signal, have been widely used because of their cost-effective fabrication, simple working principle, and easy signal processing.…”

Preparation of Bamboo-Like Carbon Nanotube Loaded Piezoresistive Polyurethane-Silicone Rubber Composite

“…These polymeric materials act as supporting substrates for the nanofiller to achieve a mechanically flexible pressure sensor [ 50 ]. PU, with its high porosity and low elastic modulus [ 51 ], provides a promising matrix material for piezoresistive sensors. The manufacturing of polyurethane-based FPPSs involves the use of dip-coating in solutions dispersed with nanofiller materials.…”