Preparation of strong adhesive waterborne coating on polyester fabric based on cation-π interaction and its application in oil/water separation

Polyethylene terephthalate (PET) is widely used in industry and daily life with its excellent mechanical and thermodynamic properties, and its surface property arising from coating has a great impact on its application. However, most coatings on PET display poor fastness and environmental pollution because of inactive surface and organic solvent. Encouraged by the cation-π interaction between the cationic and aromatic groups, we designed a strong adhesive waterborne polyurethane (PU) coating on PET fabric for oil/water separation. The bis(2-hydroxyethyl) dimethylammonium chloride (BDAC) in polymer not only provides PU with self-emulsification property, but also endows the coating with strong cation-π interaction with PET substrate. The effect of hydrophilic group on the property of PU dispersion was investigated by adjusting the content of BDAC. In addition, the interaction of optimized PU dispersion with single PET fiber was also quantitatively studied by adhesion force and surface tension measurements. It was demonstrated that the introduction of BDAC as cationic group resulted in a strong adhesion of PU coating on PET fabric and the coating could withstand various harsh environments. Furthermore, the synthesized coating could be used as an intermediate adhesive layer to anchor fumed SiO2 on PET fabric, improving the surface roughness and hydrophobicity of the substrate. The modified fabric exhibited remarkable durability and excellent ability for oil/water separation.