Zein–sodium alginate based microcapsules for essence controlled releasing coating as leather finishes

Currently the development and application of leather are strongly limited by the peculiar smells of the leather itself and the chemical residues in the leather. However, traditional finishing materials containing essences have a short release period, but also weaken the mechanical properties of the coating. Herein, we first report a route of crafting essence controlled releasing coatings as leather finishes comprising zein–sodium alginate microcapsules loaded with Artemisia argyi essence ([email protected]) and casein modified by caprolactam (Ca-Cpl), of which [email protected] was prepared by anti-solvent precipitation technique before physically blended with Ca-Cpl to prepare composite coating. The results showed that the average particle size of [email protected] was about 5.7 μm, and the accumulative release rate of essence in [email protected] was 48.3% after continuous release for 120 h. Besides, the [email protected]+Ca-Cpl film is transparent and has good flexibility, with pores and microspheres uniformly distributed inside. Moreover, the inhibition zones of the leather samples finished by [email protected]+Ca-Cpl against Escherichia coli (E. coli) (1st d) and Staphylococcus aureus (S. aureus) (2nd d) were 2.6 cm and 4.2 cm respectively, which hardly changed after continuing culture for 2 days. Moreover, expected sanitary, mechanical and antibacterial properties of the leather finished could be given by [email protected] based composites. This study provides a feasible way to prepare composite coating materials with functionality based on natural protein, polysaccharide and plant essence.