Superhydrophobic silicone/PTFE films for biocompatible application in encapsulation of implantable microelectronics devices

In this paper, the novel biocompatible materials were created on the basis of creation of the bio-inert superhydrophobic surfaces using a heat curable polydimethylsiloxane (PDMS, Sylgard 184, a product of Dow Corning) and polytetrafluoroethylene (PTFE) particles. The incorporation of PTFE nanoparticles in the PDMS matrix allows the formulation of superhydrophobic films with contact angles of ~160deg. Evaluation of the effect of PTFE particle size on the superhydrophobicity was conducted by using a larger particle size (5 mum); the resulting film yielded a contact angle of only 136.4deg. The effect of the ratio of PTFE to PDMS resin and the ratio of PDMS resin to solvent were investigated. The coating methods including dipcoating, barcoating and spincoating were also investigated and SEM and AFM imaging of the micro/nano structured surface was conducted. And the surface chemistry from XPS analysis and its roughness effect on the superhydrophobicity were discussed. The application of this superhydrophobic film for the anti-adhesion of cells in biocompatible encapsulation of implantable microelectronics devices were also studied using E. coli as model cells