AVS 59th Annual International Symposium and Exhibition
    Thin Film Wednesday Sessions
       Session TF-WeM

Paper TF-WeM6
Preparation of Hydrophobic Coatings on Si/SiO2 by Incorporation of Nano- and Microdiamond in a Layer-By-Layer Deposition

Wednesday, October 31, 2012, 9:40 am, Room 10

Session: Thin Films for Encapsulation, Packaging, and Biomedical Devices
Presenter: A. Diwan, Brigham Young University
Authors: A. Diwan, Brigham Young University
J. Wilcock, Brigham Young University
M.R. Linford, Brigham Young University
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Hydrophobic coatings are required in a wide variety of applications. We are preparing robust hydrophobic coatings on silicon from nano-/microdiamond and polyallylamine (PAAm) deposited in a layer-by-layer fashion. After deposition of PAAm/diamond multilayers, two different approaches were considered for preparing hydrophobic surfaces. The first involved the reaction of the amine groups of PAAm with the epoxy groups of 2-(1H,1H-perfluoroundecyl)oxirane to yield hydrophobic surfaces. However, due to the formation of hydroxyl groups in this ring opening reaction, the roll off of water drops, i.e., their receding contact angles, was poor although the surface showed high static and advancing water contact angles. The other approach, which appears to produce more robust coatings, used only nano-diamond and PAAm for the growth of electrostatically bound layers. The amine of the PAAm was reacted with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) in a closed pressure vessel at 100°C, which should provide crosslinking to the film and also active sites for subsequent reaction. The final step involved the chemical vapor deposition of a fluorinated silane (F-13 silane) to give a hydrophobic surface. The static water contact angle of a flat PAAm/GPTMS/F-13 silane surface was 107°, which showed good roll off properties. The prepared coatings are evaluated and analyzed at every step using atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy, ellipsometry for thickness measurements and water contact angles measurements.