Electrophoretic deposition of materials using lithocholic acid as a dispersant

Lithocholic acid (LCA) was used as an anionic biosurfactant for the dispersion and electrophoretic deposition (EPD) of electrically neutral materials, such as poly(tetrafluoroethylene) (PTFE) and diamond from suspensions in ethanol. The steroid structure of LCA facilitated its adsorption on PTFE and diamond, which allowed for particle charging and deposition by anodic EPD. LCA was used as a co-dispersant for the fabrication of composite PTFE-diamond coatings. PTFE coatings provided corrosion protection of stainless steel in 3% NaCl solutions. Potentiodynamic studies revealed increased corrosion potential and decreased corrosion current of coated steel in comparison with uncoated steel. Impedance spectroscopy studies and analysis of the equivalent circuit showed that PTFE coating acted a barrier for electrolyte diffusion. LCA is a promising surfactant for EPD of other hydrophobic electrically neutral materials.