Quantification of dose in plasma immersion ion implantation of polymer bone scaffolds: Probe diagnostics of a pulsed dielectric barrier discharge

We demonstrate the ability of plasma immersion ion implantation to treat all surfaces of a porous polymer structure designed to act as a bone scaffold. We prove that the internal pore surfaces receive ion bombardment by examining the ultraviolet (UV) absorption spectrum of a thin polymer sheet placed inside pores of different diameters and locations. The current-voltage characteristics of a Langmuir probe in a pulsed dielectric barrier discharge are studied and interpreted to give measurements of the ion current drawn from plasma in the pores. An existing one-dimensional model of the plasma is adapted and combined with the Langmuir probe measurements to predict the ion dose to the pore surfaces. Our prediction agrees with measurements from UV absorption.