MOLECULAR-SURFACE TAILORING OF BIOMATERIALS VIA PULSED RF PLASMA DISCHARGES

A pulsed RF plasma glow discharge is employed to demonstrate molecular level controllability of surface film deposits. Molecular composition of plasma deposited films is shown to vary in a significant manner wi th the RF duty cycle. Three fluorocarbon monomers are used to illustra te the process. All three exhibit a trend towards increased surface CF 2 content with decreasing pulsed RF duty cycle, including exclusion of oxygen. Significant variations in carbon-fluorine surface functionali ties are obtained over a controllable range of film thickness. Film gr owth rate measurements reveal the occurrence of surface reactions duri ng significant portions of the off portion of the duty cycle. Albumin adsorption on fluorocarbon-treated PET films is unchanged from PET con trols for a 100-fold range of bulk concentrations and 60-fold range of adsorption times. However, increased retention of albumin is observed following incubation with protein-denaturing sodium dodecyl sulfate s olution, the retention decreasing with increasing bulk concentration o f albumin. The increased retention of albumin suggests the treated sur faces may have promise as biocompatible materials.