AVS 46th International Symposium
    Nanometer-scale Science and Technology Division Tuesday Sessions
       Session NS1-TuM

Paper NS1-TuM7
Interphase Nanomechanical Properties in a Model Epoxy-Silane-Glass Composite as Revealed by Interfacial Force Microscopy

Tuesday, October 26, 1999, 10:20 am, Room 612

Session: Nanomechanics
Presenter: R.M. Winter, S.D. School of Mines and Technology
Authors: H. Cabibil, University of Texas, Austin
J.M. White, University of Texas, Austin
J.E. Houston, Sandia National Laboratories
R.M. Winter, S.D. School of Mines and Technology
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The interfacial force microscope (IFM), a scanning probe microscope utilizing a self-balancing differential capacitance force sensor, was used to measure directly the interphase elastic and visco-elastic properties in model epoxy-silane-glass systems. Model composites were fabricated from diglycidyl ether of bisphenol F, diethyltoluenediamine and gamma-aminopropyltrimethoxysilane; an epoxy, amine curing agent, and organosilane respectively and optical silica fibers as the reinforcement and chemical sensor. The elastic modulus was determined directly from the force profiles using a contact mechanics analysis. It was found that the elastic modulus varies significantly with respect to the bulk in a 1-5 micron region surrounding the 50 micron glass fibers. The relaxation and creep response of the interphase was probed to investigate the visco-elastic response of the interphase. An organosilane-epoxy-glass system was also developed to model the interphase region and was probed with the IFM. Visco-elastic analysis of the model interphase yields storage and loss moduli. Fourier transform infrared evanescent wave spectroscopy, utilizing the fibers or a parallelepiped (the model interphase substrate) as both a waveguide and an evanescent sensor, and x-ray photoelectron spectroscopy were used to characterize the bulk and interphase chemistry of the systems. The relationship between interphase chemistry and nanomechanical properties were examined and will be discussed. The portion of this work done at Sandia, which is a multiprogram laboratory operated by Sandia Corporation - a Lockheed Martin Company, was supported by the United States Department of Energy under Contract DE-AC04-94AL85000.