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CHEMICAL FORCE MICROSCOPY: AIDING IN THE DESIGN OF NEXT GENERATION COMPOSITES Mark A. Poggi†, Lawrence A. Bottomley†, and
Peter T. Lillehei‡ Chemical Force Microscopy/Spectroscopy are important new methods for probing interactions between molecules and surfaces. We have utilized these methods to examine the affinity of substituted alkanes with the surface of single walled carbon nanotubes (SWNT). Force volume images of SWNTs were obtained using gold-coated AFM tips functionalized with terminally-substituted alkanethiols. Analysis of these images enabled quantification of the adhesive interactions between the functionalized tip and the SWNT surface. The resultant adhesive forces were shown to be dependent upon surface topography, tip shape, and the terminal group on the alkanethiol. Additionally, nanotube "peel tests" were performed on self-assembled monolayers to further characterize the nanotube/thiol interaction. Biological modifications of the AFM tip or substrate with lipids or single stranded DNA is also of interest because it has been shown that these types of biomolecules have a high affinity for the wall of the nanotube. Since the tensile modulus, strength, and strain of SWNTs are greater than steel, they are ideal components for next generation composite materials. The information presented herein will aid in the design of new, light-weight, high-strength composite systems with uniform mechanical properties. |