Investigation of particle size effect on the performance of micro/nano capsules and composite coatings

Abstract

In this paper, a series of micro/nano capsules encapsulating linseed oil (self-healing agent) with different particle sizes (500 nm, 1.0 µm, 5.0 µm and 10.0 µm) were prepared by emulsion template method combined with photopolymerization and solvent volatilization. The sizes of micro/nano capsules were facilely and efficiently tuned by adjusting emulsifying method, emulsification time and emulsifier concentration. And the effects of the capsule size on the morphology, loading property, dispersibility and solvent resistance of capsule were investigated. The results showed that the larger capsules exhibited higher yield, loading rate and loading efficiency. In addition, the solvent resistance increased gradually with the increase of capsule size. The composite coating was prepared by dispersing the micro/nano capsules in coating matrix. The effect of the capsule sizes on the coating properties was systematically investigated. The nanocapsules were easily aggregated owing to its nano-size effect and thus showed a relatively poorer dispersibility in coating matrix. Whereas better dispersibility was observed for the larger capsules, and the coating with larger capsules showed better self-healing performance and corrosion resistance.