A series of epoxy nanostructured coatings based on diglycidyl ether of bisphenol A (DGEBA) and an isophorone diamine crosslinker was prepared. Top-down nanocomposites (3% nanofiller) were obtained by the mechanical dispersion of nanoalumina, silanized nanoalumina, and organomodified clays. Bottom-up hybrids were instead achieved after the silanization of the DGEBA resin and after cocrosslinking with tetraethylorthosilicate through a self-catalyzed sol-gel process. The curing process of the nanocomposites was studied by differential scanning calorimetry and suggested an overall increase in the crosslinking kinetics in the presence of nanoparticles. Other characterization included dynamic mechanical analysis, Buchholtz indentation hardness testing, and Taber abrasion testing. Finally, atomic force microscopy (AFM) techniques were used to study the surface morphology of the coatings and to produce nanoscratches. We concluded that, in the top-down nanocomposites, there were minor changes in the surface hardness and a slight improvement in the abrasion resistance, whereas the nanoscratch resistance assessed by AFM tests showed significantly better performances in the hybrid coatings obtained through sol-gel chemistry.

Elastomeric compounds from hydrogenated acrylonitrile butadiene rubber, organomodified clay, and perfluoropolyether (PFPE) additives were prepared. Characterization of the materials included X-ray diffraction, dynamic mechanical analysis (DMA), tensile mechanical properties testing, environmental scanning electron microscopy, and solvent permeability measurements, from which the solubility coefficient (S) and diffusion coefficient (D) values were determined. A synergistic effect of the two additives was observed because the presence of clay reduced D, whereas PFPE mainly decreased S. Increasing the mixing time facilitated the dispersion of the clay layers. DMA and the diffusivity data were used to estimate the aspect ratios of the solid inclusions in the rubber.

Model high density DNA arrays have been realized by direct deposition with Dip-Pen Nanolithography of acrylamido-functionalized oligonucleotides (23-mer) on spin-coated, flat polystyrene surfaces. A highly specific interaction between the acrylamide end functionality and polystyrene was found. The surface morphology of the model array was studied by atomic force microscopy (AFM). Spots are clearly seen both in topography and demodulation modes. The array withstands the hybridization process with label free, complementary oligonucleotides and the following cleaning procedures. The final AFM characterization showed significant changes especially in demodulation images which may be an indication that molecular recognition between complementary oligos has occurred.

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