Piezoresistive strain sensors based on conductive elastomeric nanocomposites of silicone rubber with carbon nanotubes

• Grant number: 24/01236-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2024
• End date: April 30, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Rafael Barbosa
• Grantee: João Victor Bergamasco Gremaschi
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Investigating the processing method and resulting properties of conductive silicone rubber nanocomposites to act as piezoresistive sensors is a promising line of research based on the great needs for flexible electronic devices. Carbon-based fillers can be incorporated with the aim of improving electrical properties in polymers, in particular, graphene and its derivatives, carbon nanotubes (CNT) and conductive amorphous carbons (NFC). The solution, melt and latex suspension mixing methods are the main ones when it comes to incorporating fillers into elastomers. However, mixtures in the liquid state become more efficient, due to the possibility of using high-power sonication to deagglomerate and disperse nanometric fillers. Therefore, this work will evaluate the incorporation of conductive nanotubes in a silicone rubber matrix solubilized in tetrahydrofuran (THF) to increase electrical conductivity. The rubber will also be characterized as a strain sensor, with simultaneous measurement of electrical conductivity and elongation in tension carried out by a uniaxial testing machine. Both electrical conductivity and piezoresistivity results will be obtained by Electrochemical Impedance Spectroscopy (EIS), which provides several specific electrical transport properties in solid materials. Differential scanning calorimetry (DSC) and thermogravimetry (TGA) tests will be performed to evaluate the behavior and thermal stability of the prepared nanocomposites. With this study, we intend to advance the development of elastomer processing technologies, aiming at better incorporation of nanometric particles, and also in the application of these materials in deformation sensing in engineering systems in general.