AVS 46th International Symposium
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThM

Paper PS-ThM8
Plasma Modification of Polymeric Membranes

Thursday, October 28, 1999, 10:40 am, Room 609

Session: Plasma-Surface Interactions II
Presenter: M.L. Steen, Colorado State University
Authors: M.L. Steen, Colorado State University
E.R. Fisher, Colorado State University
N.E. Capps, Colorado State University
E.D. Havey, Colorado State University
Correspondent: Click to Email
Since most polymers have intrinsically low surface energy, poor adhesion and wettability severely limit many applications. The adhesion properties and wettability of polymers can be improved through plasma surface modification. The surface properties altered by plasma treatment include chemical composition, wettability and adhesion. These properties depend on the interaction of the plasma with the surface. Specifically, the plasma can often erode the polymer, abstracting atoms and breaking polymer chains. Reactive species in the plasma can interact at these active sites, thereby, implanting new functional groups. Alternatively, the plasma can also change the surface properties of the polymer by depositing a thin, conformal film on the surface. The primary goal of our research is to develop plasma-based treatments that render the surface of hydrophobic polymeric membranes permanently hydrophilic. A related goal is to investigate plasma treatments that produce highly hydrophobic materials. We have done an extensive parameter study of many plasma systems. For the hydrophilic treatments, we have studied OH implantation from pure H@sub 2@O plasmas and H@sub 2@O plasmas with a diluent gas, such as Ar. For the hydrophobic treatments, we have studied F atom implantation from CF@sub 4@ plasma. The membrane can also be rendered hydrophobic by depositing a fluorocarbon film from a pulsed CHF@sub 3@ plasma. We have also combined these two approaches by first depositing a hydrocarbon film from CH@sub 4@ and then fluorinating that film with a reactive gas, such as CF@sub 4@. Results from bubble point measurements, porometry, SEM, contact-angle measurements and gas permeability identify several plasma treatments that successfully impart these membranes with the desired surface properties. Specifically, Ar/H@sub 2@O, CF@sub 4@, CHF@sub 3@ and CH@sub 4@/CF@sub 4@ plasma treatments will be discussed.