NEW CONCEPTS OF COLLOID SCIENCE: NANO-ADSORBENT AND PROTOMICELLE

Abstract

Large molecules of dyes or other substances can play the role of a nano-adsorbent in aqueous surfactant solutions and, coated with surfactant molecules, resemble surfactant micelles with a solubilizate. Such micelle-like particles were called protomicelles. Their formation does not require a critical micelle concentration (CMC) and begins immediately when the surfactant is introduced into the solution. In this spectrophotometric study of Nile red (NR) in aqueous solutions of nonanoic acid (NOA), the case where protomicelles are more important than micelles is demonstrated for the first time. It has been shown that the solubilization of NR in both premicellar and micellar solutions proceeds through protomicelles rather than NOA micelles. The article also contains a theoretical part. In it, on the basis of the chemical potential of the nano-adsorbent, it is proved that the addition of a surfactant to a solution always increases the solubility of the nano-adsorbent. The dependence of adsorption on the curvature of the nano-adsorbent surface is considered and it is shown that the adsorption equations for flat surfaces can be used for curved surfaces with high accuracy.