Interactions of polyvinyl acetate dispersions with nanostructured superhydrophilic and superhydrophobic Ti6Al4V alloy surfaces

Nanostructured bilayer thin films with superhydrophobic and superhydrophilic surfaces were prepared using Ti6Al4V alloy substrates which allowed for the comparative analysis of polyvinyl acetate (PVAc) particle adsorption as a function of the interface structure. The PVAc particles were obtained from emulsion polymerization of vinyl acetate. A superhydrophilic TiO2 nanofiber-based 3D network was created on the Ti6Al4V alloy substrate by application of a hydrothermal method. Subsequent UV-grafting of ultra-thin polydimethylsiloxane (PDMS) layers resulted in a superhydrophobic surface. The modification steps were followed via Diffuse Reflectance Infrared Fourier Transform Spectroscopy, X-ray Photoelectron Spectroscopy, Field Emission-Scanning Electron Microscopy, contact angle and Electrochemical Impedance Spectroscopy. A mechanism for the adsorption of PVAc at the two electrolyte/substrate interfaces could be revealed. Superhydrophobic and superhydrophilic surfaces were created based on a Ti-alloy by combining topography and chemistry on a nanometer scale. Polymeric polyvinyl acetate particle fouling was significantly reduced by generation and employment of a superhydrophobic surface. Particle/surface interactions were explained based on the performed experiments and the results were summarized in an interface model.