Surface activity of N-graphene quantum dot in presence of CTAB surfactant

Abstract

An interface can be subtly engineered utilizing nanoparticle-surfactant interactions by controlling surface activity and surface charge balancing. In this research, the effect of N-doped Graphene Quantum Dot particles (N-GQDs) and Cetyl trimethylammonium bromide surfactant (CTAB) presence in the air/water interface is explored. We found on the study of interplay of N-GQD with CTAB that N-GQDs are surface active particles. Thereafter, the effect of concentration ratio of CTAB to N-GQD on surface tension and elasticity is investigated up to critical micelle concentration (CMC). The results demonstrate the surface activity of N-GQDs when there is no surfactant molecules (1 wt% N-GQD, surface tension (ST) ∼53). In addition, the results manifest that due to CTAB molecules' attachment to the N-GQD particles, more efficient surface-active mixtures are created. At higher surfactant loadings, the excess CTAB monomers compete with CTAB/ N-GQDs mixtures to reach the interfaces, causing mixture to come back into the bulk of liquid verified by elasticity evaluations. The preparation of N-GQDs and as a result its mixture includes economical and easy experimental protocols, and according to the synergistic effects defeat the individual components constraints i.e. –at 1% N-GQD+0.25 CMC CTAB the dynamic surface tension lies below pure CTAB CMC line.