Enhancement of Porosity and Surface Roughness of Cured Phenolic Resin by Ion Implantation

We present recent results using ions such as C., O, Si, Fe, Zn, and Au at energies between 100 keV to 10 MeV to increase the roughness and porosity of the partially and fully cured precursor phenolic resins. The fully cured phenolic resin is called Glassy Polymeric Carbon (GPC). GPC is chemically inert, biocompatible and useful for medical applications, such as heart valves and other prosthetic devices. Ion implantation enhances biological cell/tissue growth on, and tissue adhesion to, prosthetic devices made from GPC. We have previously shown that increased porosity of GPC is also useful for drug delivery devices. The porosity of the ion implanted partially and fully cured precursor phenolic resins was measured by introducing lithium from a molten LiCl salt into each sample. By using Li(p,2α) nuclear reaction analysis (NRA) we measured the concentration of Li retention in the pre- and post-implanted samples. The surface roughness was measured using optical microscopy. The curing process was monitored using micro-Raman microscopy. We have correlated the NRA measurements of increased pore availability with the observations of increased surface roughness.