Nanoscale surface modification is reported for styrene butadiene rubber using an electrically biased conducting atomic force microscope tip. Under appropriate bias conditions, the local electric field magnitude is of the order of 10 8 -10 9 V m −1 , which is sufficiently large to initiate cross-linking in the rubber. Peaklike surface features, surrounded by a circular trough and a raised ring, are created by careful and controlled retraction of the biased tip. The features' aspect ratios can be controlled by modifying the tip retraction protocol, tip geometry, and bias voltage. Typical feature dimensions reported here vary from approximately ͑0.5-10͒-nm high and up to several hundreds of nanometer in diameter. Although the temperature of the rubber is above the glass transition and the rubber is in a viscous state, the features are stable over a period of several days once created-which is believed to be due to cross-linking of the rubber during feature formation. Modeling of the electric field distribution in the vicinity of the tip is presented, which strongly supports the assertion that the resulting nonuniform electric field induces nanostructure formation and initiates cross-linking. A mechanism is proposed whereby source material is redistributed in the proximity of the tip/surface region to form the observed features.

Water condensation is shown to have a major influence on electric charge transport and nanostructure formation in polymer-, and semiconductor-thin-film surfaces in the proximity of a biased Atomic Force Microscope (AFM) tip. The water forms a meniscus bridge between the AFM tip and the surface to form a three-component system comprised of the AFM tip, water meniscus, and the surface. The associated electric field in the meniscus is spatially non-uniform and has a magnitude of the order of 10 8 -10 10 Vm -1 . An intensive experimental analysis of the input and output electric currents in the AFM tip/water meniscus/surface system, performed at various relative humidity levels between 10 and 60%, indicates that the magnitude of the output current, drained from surface, reaches values as large as several μA which exceeds the input current, injected via the AFM tip (0.01-10 nA), by at least an order of magnitude. This effect is particularly evident when the relative humidity is greater than 20-25%, suggesting that the water meniscus is ionized by the strong electric field to produce electrons. Since the method described here for nanopatterning is applicable for materials with significantly different physical, electronic, and optical properties, and is dependent largely on the ambient humidity level and the strength of the electric field, it is suggested that the method may be extended to a variety of other materials.