AVS 52nd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP13
Functionalization of Rough Polymer Surfaces and Porous Micron-Sized Beads Using Atmospheric Pressure Plasmas@footnote 1@

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Plasma Science and Technology Poster Session
Presenter: A.N. Bhoj, University of Illinois at Urbana-Champaign
Authors: A.N. Bhoj, University of Illinois at Urbana-Champaign
M.J. Kushner, Iowa State University
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Pulsed atmospheric pressure plasma discharges, such as corona and dielectric barrier discharge devices, are commonly used to functionalize surfaces (e.g., polymer sheets) with the advantages of high throughput and in-line continuous processing. These materials have surface roughness of 100s nm to 10s µm often resulting from the manufacturing process. Porous materials also have highly non-planar surfaces that can be functionalized for novel applications such as drug delivery. In this paper, results from a computational multiscale investigation of atmospheric pressure plasma treatment of rough polymer surfaces and porous polymeric beads are discussed. The investigation was conducted with a 2-dimensional plasma hydrodynamics model using an unstructured mesh capable of resolving a dynamic range of 1000 in spatial scale.@footnote 2@ This capability enables a multi-scale approach in which the reactor scale plasma hydrodynamics and penetration of plasma produced species into surface structures can be simultaneously addressed. A surface kinetics model is integrated with the plasma hydrodynamics model to assess the uniformity of treatment of the surface structures. The model geometry is a dielectric barrier-corona configuration at atmospheric pressure with a gap of a few mm to the surface. Nitrogen-containing gas mixtures produce amine functionalities on rough polymer surfaces and porous polymer beads of 10s µm sizes with pore diameters less than 2 µm. Radicals and ions generated in the plasma diffuse through the pores and access the internal surfaces, a process that depends on polarity of the corona. The uniformity of treatment of the nooks-and-crannies of the rough surfaces and on the internal surfaces of the polymer beads depends on the relative rates of transport and reaction limited processes, and evolves over successive pulses as the surface functionalization is saturated. @FootnoteText@ @footnote 1@ Work supported by NSF (CTS03-15353). @footnote 2@ A. N. Bhoj and M. J. Kushner, J. Phys. D. 37, 2910 (2004).