We study epitaxial graphene on the 6H-SiC(0001) surface under ambient conditions using frequency-modulation atomic force microscopy. We observe large terraces with a self-assembled stripe structure within a highly adsorbate covered surface on top of the graphene. To identify the origin of the structure, we compare the experimental data on graphene with calculations and experiments on graphite that predict the formation of a solid-gas monolayer in the solid-liquid interface of hydrophobic surfaces.
View Article and Find Full Text PDFThe aim of this in vitro study was to evaluate the influence of physicochemical surface properties of resin-based composites on Streptococcus mutans biofilm formation. Specimens were prepared from each of four resin-based composites by polymerization against Mylar strips. Half of the number of specimens received no further surface treatment, whereas the other half were subjected to a polishing treatment.
View Article and Find Full Text PDFWe report on atomic force microscopy (AFM) in ambient and liquid environments with the qPlus sensor, a force sensor based on a quartz tuning fork with an all-electrical deflection measurement scheme. Small amplitudes, stiff sensors with bulk diamond tips and high Q values in air and liquid allow to obtain high resolution images. The noise sources in air and liquid are analyzed and compared for standard silicon cantilevers and qPlus sensors.
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