Evaluation of agar spray for the development of a green surfactant-free rigid emulsions

Abstract

This study addresses growing environmental and health concerns in conservation-restoration by exploring a sustainable method for varnish removal. It investigates the use of nebulized Agar hydrocolloid to formulate surfactant-free oil-in-water emulsions, even with green solvents like dibasic ester (DBE), which are difficult to mix with water. Agar gel loaded with DBE was nebulized to produce rigid, surfactant-free agar spray emulsions (ASE) for varnish removal. The study evaluated jet properties, emulsion stability, varnish removal efficiency, and possible adverse effects, comparing the nebulized method with traditional high-speed mixing techniques. Results showed nebulization affected droplet size distribution and improved emulsion stability. The green spray emulsion effectively removed dammar varnish from an oil painting without visible degradation, as shown by microscopic observations, SEM-EDS, and FTIR analyses. This biodegradable, non-toxic, surfactant-free emulsion offers a cost-effective, eco-friendly, and promising alternative for modern conservation practices.