Low-temperature decomposable industrial surfactant for stabilization of few-layered graphene in water

Abstract

Surface-active agents, such as surfactant molecules, are essential for stabilizing liquid-exfoliated graphene and other 2D nanosheets in water through electrostatic or steric repulsion. It is important to note that surfactants are no longer necessary for solutions converted into thin films for electronic devices, sensors, and composite applications. High-temperature (∼400–500 °C) thermal annealing is one of the performed methods to remove surfactant molecules. However, the surfactant residues present on the graphene nanosheets by post-annealing may adversely impact the electronic properties of the graphene film, potentially resulting in additional doping and defects. To address this challenge, we report a low-temperature decomposable (∼320 °C), eco-friendly and industrially viable surfactant, i.e., coco-glucoside, for the efficient liquid-phase exfoliation and stabilization of graphene nanosheets in water. Compared with the well-studied surfactants in liquid exfoliation such as sodium dodecyl benzene sulphonate (SDBS) and sodium cholate (SC), ∼90 % of this surfactant molecules completely decomposed at ∼320 °C in an air atmosphere for coco-glucoside. Electrical conductivity studies suggested that annealing at 320 °C enhanced the conductivity by 15 times for the coco glucoside-stabilized graphene film; however, marginal change in the conductivity was observed for the SDBS and SC-stabilized graphene film. To demonstrate the viability of the concept, a wallpaper-based rapid fire alarm application utilizing coco glucoside-stabilized graphene/cellulose paper was demonstrated.