Mechanical and self-healing properties of a water-based acrylic latex containing linseed oil filled microcapsules: Effect of pre-silanization of microcapsules' shell compound

In this study, mechanical properties and self-healing performance of a water-based acrylic coating containing linseed oil-filled ethyl cellulose (EC) microcapsules were evaluated. In order to improve interfacial interactions between microcapsules' shell and their surrounding latex matrix, EC was treated with three different trimethoxysilane coupling agents before microencapsulation process. Water-based acrylic coatings containing various amounts of different microcapsules were prepared and their tensile properties were studied. The effect of silane pre-treatment of microcapsules' shell on the self-healing performance of the coating was also evaluated via optical microscopy, UV–visible spectroscopy, AFM and SEM. Water vapor transmission (WVT) of intact and healed scratched coating samples was measured and their healing efficiency values calculated.It was found that the addition of microcapsules with pre-silanized shell compound has a positive effect on the tensile and mechanical properties of the coating. The degree of this effect depended on the silane type and microcapsules' loading wt% in the coating material. Sample containing microcapsules with amino-based silane treatment revealed appropriate tensile properties among the others owing to better compatibility with polymeric matrix, improving barrier properties of scratched area by releasing of hydrophobic oil and therefore, minimizing the penetration of water and water vapor through the coating layer.