We redevelop a theoretical model that, in conjunction with atomic force microscopy (AFM), can be used as a noninvasive method for determination of the elastic modulus of a polymer nanodroplet residing on a flat, rigid substrate. The model is a continuum theory that combines surface and elasticity theories for prediction of the droplet's elastic modulus, given experimental measurement of its adsorbed height. Utilization of AFM-measured heights for relevant droplets reported in the literature and from our own experiments illustrated the following: the significance of both surface and elasticity effects in determining a polymer droplet's spreading behavior; the extent of a continuum theory's validity as one approaches the nanoscale; and a droplet size effect on the elastic modulus.

Experimental investigations of plastic flow have demonstrated temporal intermittency as deformation proceeds in a series of intermittent bursts with scale-free size distribution. In the present investigation, a corresponding spatial intermittency is demonstrated for plastic flow of KCl single crystals. Deformation bursts lead to large surface steps with a height distribution that is consistent with the distribution of strain increments in deformation of micro-columns, and the energy distribution of acoustic emission bursts observed in deformation of macroscopic single crystal samples of a wide class of materials.

The use of low-energy femtosecond laser beam combined with chemical etching has been proven to be an efficient method to fabricate three-dimensional structures in fused silica. For high-volume application, this technology -like other serial processes -suffers from a moderate production rate. Here, we show that femtosecond laser can also be employed to fabricate silica molds and other patterned surfaces, including surfaces with high aspect ratio features (> 10). Through appropriate tailoring of silica"s surface property and subsequent creation of, for instance, simple elastomeric molding, new opportunities for the indirect 3D, multi-scale spatial characterization of deep laser-fabricated microstructures come along. We demonstrate that those moldings are characterized by a high fidelity (down to the nanometer scale) to the silica mold. These results further advance the applicability of femtosecond laser processing to glass.

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We use scanning white-light interferometry to investigate the surface morphology evolution of KCl single crystals during plastic deformation in hardening stages I and II. We demonstrate that during deformation initially almost smooth as-cleaved surfaces develop self-affine roughness over several orders of magnitude in scale. The roughness exponent ζ of one-dimensional surface profiles is found to be close to 0.7. The kinetics of surface roughening is investigated, and the rate of roughening is shown to correlate with the hardening rate. During hardening stage II, a marked acceleration of the surface roughening rate is observed. The morphology of surface profiles changes at the transition between hardening stages I and II.