Methods for patterning metal thin films at the microscale and nanoscale by applying the patterns to metallic and polymeric materials for use in shape and deformation measurements in a scanning electron microsope (SEM) or other high magnification imaging system are described. In one approach, thin films of metallic materials (e.g., Au, Ag, Cu, and Cr) are applied to a variety of substrates. The coated samples are then placed into a reaction vessel, where the specimens are heated and exposed to a nitrogen atmosphere saturated with selected volatile chemicals. This process results in nano-scale remodeling of the metallic films, thereby affording high contrast random patterns with different morphologies. In a second approach, thin films of metallic materials, including gold and silver, also have been applied using a simplified UV photolithographic method requiring a minimum amount of laboratory preparation. Using selected substrates, both methods have been used successfully to transfer patterns onto polymeric and metallic materials ranging from 50-500 nanometers with chemical vapor rearrangement and 2 to 20 microns with UV photolithography, providing a pattern that can be used with digital image correlation to quantify both the surface profile and also surface deformations at reduced length scales.

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A method is presented for patterning polymers with nanoscale gold networks and using the pattern to measure strain in the polymer. A gold film is first coated on a porous alumina template. After coating, the template is impressed into a polymer, and the template is dissolved to leave a continuous metal network on or slightly below the surface of the polymer. The network has a random structure and is electrically conductive and has potential applicability to structural health monitoring. We show that it can be used as a means of measuring deformation through changes in electrical conductivity and continuity and also as a means to measure local material response during controlled loading.

We report studies on the modifications induced by the evaporation of copper overlayers on a self-assembled monolayer (SAM) of the oligo(phenylene-ethynyl) dithiol, 1-thio-4-[4'-[(4'-thio)phenylethynyl]-1'-ethynyl]-benzene (TTPEB). These SAMs were characterized after deposition from a tetrahydrofuran solution on polycrystalline gold substrates and after copper evaporation and its subsequent removal by nitric acid. Monolayers were studied via cyclic voltammetry (CV), UV-vis multiwavelength ellipsometry, external reflectance infrared (IR) spectroscopy, and ion scattering spectroscopy (ISS). The results obtained indicate that TTPEB SAMs display the same packing characteristics before and after copper evaporation and removal. However, as shown by IR spectroscopy, the monolayers undergo a reorganization process that involves an increase in tilt angle accompanied by rotation of aromatic rings that results in a decrease in the average molecular twist angle. ISS data suggest that copper diffuses through the monolayer after copper evaporation, a result that is significant for applications of this molecule in molecular electronic devices.