AVS 51st International Symposium
    Advanced Surface Engineering Monday Sessions
       Session SE-MoM

Paper SE-MoM11
Nano-coatings for Complex Uneven Surfaces Cellular Foams & Nano-fibers of Carbon

Monday, November 15, 2004, 11:40 am, Room 303D

Session: Nanolayered and Gradient Coatings for Surface Engineering
Presenter: R.V. Pulikollu, Wright State University
Authors: S.M. Mukhopadhyay, Wright State University
R.V. Pulikollu, Wright State University
P.P. Joshi, Wright State University
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The concept of surface coatings to enhance or prevent bonding with a second phase is not new, but when the surface in question has complex shape, and the coating needs to be effective at the nanometer scale, new challenges emerge. In this presentation, effectiveness of plasma-assisted nano-coatings (4-5nm thick) on two carbon structures will be presented. These are: (i) microcellular foam that has about 80% porosity and the surface consists of open, interconnected cell walls, and (ii) vapor-grown fibers having diameter of about 200nm. Both these structures are useful as reinforcing materials for composites. Coatings for enhancement surface wettability are obtained in microwave plasma using siloxanes. This treatment forms a strongly bound SiO2-type layer on the surface and causes noticeable enhancement of polar fluid infiltration in these materials. This results in micro-structural differences and enhancement of mechanical properties of composites formed. A different type of coating, that makes the surface inert by attaching CF2 groups on it, is effective in making these surfaces moisture-repellent. This coating appears to influence composite behavior in different ways. Additional aspects of these coatings, specific to different applications, such as bonding with metals and polymers, and possibility of creating multi-layer and multi-functional nano-coatings will be discussed.