Multifunctional properties of chemically reduced graphene oxide and silicone rubber composite: Facile synthesis and application as soft composites for piezoelectric energy harvesting

Abstract

The 6th element of the periodic table is undoubtedly one of the most incredible aspects of creation. Graphene has a 2-D sheet structure comprised of strong covalent bonds between sp2 hybridized carbon atoms and has attracted much research interest because of its unique physicochemical properties. However, the controlled syntheses of mono-layered and few-layered graphene remain topics of research concern. In the present work, chemically reduced graphene oxide (CRGO) was synthesized by ‘top-down’ using the modified Hummers’ method. CRGO and room-temperature-vulcanized silicone rubber (RTV-SR) were mixed to prepare composites with different CRGO loadings. We found that as little as 2 per hundred parts of rubber [phr] CRGO in RTV-SR transformed the normally rigid RTV-SR into a soft composite with a hardness decrease to 15. Moreover, the compressive modulus falls to 0.6 MPa. However, the dissipation losses decrease at 2 phr CRGO, which is a good property. For tensile mechanical properties, the fracture strain increases to 100% while tensile strength falls sharply to 0.1 MPa. Moreover, the electrical conductivity increases as the amount of CRGO increases. So, composite with soft nature and higher electrical properties are useful for various applications such as soft robotics or soft piezoelectric energy harvesting. In this work, the piezoelectric energy harvesting was performed by monitoring the output voltages generated. Output voltages were stable for RTV-SR but increased with increasing cycle number for RTV-SR/CRGO-based composites. This study provides insights into the use of soft RTV-SR/CRGO composites for soft robotics, actuation, energy harvesting, and vehicle applications.

Keywords

• polymer composites
• chemically reduced graphene oxide
• silicone rubber