Comparing the nanoscale topography and interface properties of chitosan films containing free and nano-encapsulated copaiba essential oil: An atomic force microscopy (AFM) and Fractal Geometry study

Abstract

This article compared chitosan films containing copaiba essential oil (CO) and nano-encapsulated CO using nanoscaled topographic characteristics and interface properties. The CO-loaded nanocapsules (CO-NC) were prepared by the polymer nanoprecipitation method, whereas the composite films were produced by the casting method. The films’ surface was evaluated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Wettability and adhesion were also investigated by measuring the contact angle and AFM. The results suggested that the film’s surface containing CO-NC presented characteristics that favor interface interactions at the nanoscale. Furthermore, these films showed greater interaction with water and superior adhesion force than the control and CO-loaded chitosan films. Thus, considering the surface characteristics and the evaluated properties, CO-NC seems to be a promising alternative for incorporating CO in chitosan films.