Particle functionalization and encapsulation by initiated chemical vapor deposition (iCVD)

Initiated chemical vapor deposition (iCVD) represents a novel CVD method for functionalization and encapsulation of particle substrates with polymeric materials. Three demonstrations of iCVD coatings on particle substrates are described. In the first, iCVD polytetrafluoroethylene (PTFE) coatings on an array of vertically aligned carbon nanotubes created a superhydrophobic surface. Second, iCVD polyglycidyl methacrylate (PGMA) coatings on microparticles and nanotubes provided reactive surfaces for subsequent binding to produce fluorescent and high refractive index coatings. Finally, iCVD methacrylic acid copolymers on ibuprofen microcrystals delivered enteric drug release properties based on the pH-responsive swelling behavior of the copolymers. Mathematical modeling suggested surface-driven iCVD polymerization kinetics that were analogous to liquid-phase free radical polymerization.