AVS 58th Annual International Symposium and Exhibition
    Plasma Science and Technology Division Friday Sessions
       Session PS-FrM

Paper PS-FrM1
Delivering Activation Energy to Surfaces in Atmospheric Pressure Plasmas: Local and Remote

Friday, November 4, 2011, 8:20 am, Room 201

Session: Plasma Modeling
Presenter: Mark Kushner, University of Michigan
Authors: Z. Xiong, University of Michigan
N.Yu. Babaeva, University of Michigan
M.J. Kushner, University of Michigan
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Non-equilibrium atmospheric pressure plasmas (APPs) are efficient at producing chemically reactive environments by electron impact dissociation and ionization of feedstock gases. Other than generating UV photon fluxes, APPs are not thought to be sources of non-thermal activation energy in the form of energetic ions or hot atoms. Athough mean free paths of ions may be less than 1 micron, the transient production of electric fields of 100s kV/cm to 1 MV/cm when the ionization fronts of streamers intersect with surfaces provide the possibility of accelerating ions to many to tens of eV. This high quality delivery of activation energy is a function of not only the properties of the streamer but also depends on the properties of the surface. For example, delivery of high energy ions to the surface of a bulk polymer may differ from a layered polymer due to differences in their capacitive properties. These differences extend to organic material as well – the deliver of energetic ions to cells and tissue will depend on their respective dielectric properties and those of the surrounding medium. Delivery of high quality activation energy in any form (photons or ions) to remote sites or locations is challenged by line-of-site issues and the charging of surrounding materials that may reduce ion energies. Being able to deliver activation energy to the crevices of rough surfaces may be important in the context of plasma sterilization. In this talk, results from modeling studies of atmospheric pressure plasma streamers and jets intersecting with dielectric surfaces will be discussed. The delivery of activation energy by ions and photons to rough surfaces will be discussed in the context of polymer modification and sterilization. Plasma sources will include directly applied dielectric barrier discharges and remote plasma source delivered by capillary tubes. * Work supported by the Department of Energy Office of Fusion Energy Sciences.