Multi-stimuli responsive smart elastomeric hyperbranched polyurethane/reduced graphene oxide nanocomposites

Abstract

In this report, a tough elastomeric hyperbranched polyurethane/reduced graphene oxide (HPU/RGO) nanocomposite was fabricated by an in situ polymerization technique. Reduction of graphene oxide was carried out by a green sonochemical approach using the combined effect of sonication and Fe³⁺ ions in presence of Colocasia esculenta leaves aqueous extract. The reduction occurred only in 3 min, while 8 min was required without sonication. Prepared RGO and nanocomposites were characterized by different spectroscopic and analytical tools. The nanocomposite demonstrated excellent thermal stability and mechanical properties, such as tensile strength (27.8 MPa), tensile modulus (36.3 MPa) and toughness (116 MJ m⁻³). The nanocomposite also exhibited outstanding multi-stimuli responsive shape memory behaviour under direct sunlight, microwave (360 W) and heat energy (60 °C). The performance of the nanocomposite was dependent on the loading of RGO (0.5–2.5 wt%). Thus, these nanocomposites have tremendous potential to be used as advanced non-contact triggered smart materials for different applications, including biomedical.