Fabrication of a Hydrophobic Coating Using Acacia mearnsii De Wild Tannin Melamine Formaldehyde Microcapsules

The aim of this study is to develop and investigate the effect of applying microcapsules containing a melamine formaldehyde resin shell and a tannin extract as a core to form a hydrophobic coating. The microcapsules were obtained by in situ polymerization. Morphological analysis was performed by focused ion beam/scanning electron microscopy. The chemical composition of the tannin extract, the melamine formaldehyde resin, and the polymeric microcapsules with the core of the tannin extract was determined by Fourier transform infrared spectroscopy. The thermal stability of tannin, melamine formaldehyde resin, and tannin microcapsules was investigated by thermogravimetric analysis. In addition, the durability of the coating over time was tested in an environmental test chamber. The polymeric microcapsules containing tannin extract are quasi-spherical, rough, and dense, with a diameter ranging from 1 to 5 μm and a shell thickness of 50 nm. The coating exhibited a hierarchical structure with improved hydrophobic properties, resulting in a contact angle of up to 148°.