Exploring two-dimensional soap-foam films using fullerene (C60) nanosensors

Abstract

A large number of studies have been devoted to the investigation of foam structure formation, characteristics, and stability. In this paper, we use fullerene (C60) spheres as Raman active nanosensors to probe the local chemical environment in a two-dimensional soap foam. It has been found that the position of the Raman active pentagon pinch mode around 1469 cm−1 shifts to lower wave numbers with the increase in the angle between foam-cell boundaries. The observed shift is due to changes in the local chemical interaction between the nanosensor and its environment. The study demonstrates that fullerenes may be used as sensitive nanoscale sensors to probe the local chemical potential in soft and interfacial materials, and more importantly in thermodynamically small systems.