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Nanoscale science and technology has today mainly focused on the fabrication of nano devices. In this paper, we study the use of lithography process to build the desired nanostructures directly. Nanolithography on polymethylmethacrylate (PMMA) surface is carried out by using Atomic Force Microscope (AFM) equipped with silicon tip, in contact mode. The analysis of the results shows that the depth of scratches increases with the increase of applied normal force. The scanning velocity is also shown to influence the AFM patterning process. As the scanning velocity increases, the scratch depth decreases. The influence of time and number of scratching cycles is also investigated.

Predicting how proteins fold and adsorb onto surfaces is a complex problem of strong relevance to the health and environmental sectors. In this work, two nano-patterning techniques, namely focused ion beam (FIB) milling and atomic force microscopy (AFM) nanoindentation were used to develop hydrogenated amorphous carbon (a-C:H) model surfaces with similar nano-topography but different local composition. On the un-patterned surfaces, bovine plasma fibrinogen (BPF) resulted in a thicker and rougher adsorbed film than bovine serum albumin (BSA), although FTIR analysis indicated that, the secondary structure of the proteins changed similarly, with an increase of the β-sheet component (+ 27% and + 34% for BSA and BPF, respectively). AFM analysis on the FIB-patterned surfaces indicates that patterning can modify specific protein adsorption behaviors. Moreover, the patterns were compared by imaging the AFM tip/surface adhesive force for BSA adsorbed on either AFM tips or patterned surfaces. The results show an electrostatic interaction between the implanted Ga + and BSA surface, modifying the adsorption behavior and the adhesive force. Modelling this interaction gave an estimate of the surface charge per protein, a significantly lower value than in dilute solution (− 1.8e instead of -18e). This finding is indicative of protein misfolding, as detected in the FTIR analysis. [ABSTRACT FROM AUTHOR]

Abstract: Nanopatterning of silicon surfaces by means of He+ ion implantation through self-organized colloidal masks is reported for the first time. Nanosphere lithography (NSL) masks with mask openings of 46–230nm width were deposited on Si(100) wafers. He+ ions were implanted through these masks in order to induce a local cavity formation and Si surface swelling. The surface morphology and the subsurface structure were studied using atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM), respectively, as a function of mask and implantation parameters. It is demonstrated that regular arrays of both individual hillocks and trough-like circular rings can be generated. [Copyright &y& Elsevier]

Abstract: Micro-dot arrays and micro-walls of acrylic acid/melamine resin were fabricated on aluminum by anodizing, atomic force microscope (AFM) probe processing, and electrophoretic deposition. Barrier type anodic oxide films of 15nm thickness were formed on aluminum and then the specimen was scratched with an AFM probe in a solution containing acrylic acid/melamine resin nano-particles to remove the anodic oxide film locally. After scratching, the specimen was anodically polarized to deposit acrylic acid/melamine resin electrophoretically at the film-removed area. The resin deposited on the specimen was finally cured by heating. It was found that scratching with the AFM probe on open circuit leads to the contamination of the probe with resin, due to positive shifts in the potential during scratching. Scratching of the specimen under potentiostatic conditions at −1.0V, however, resulted in successful resin deposition at the film-removed area without probe contamination. The rate of resin deposition increased as the specimen potential becomes more positive during electrophoretic deposition. Arrays of resin dots with a few to several tens μm diameter and 100–1000nm height, and resin walls with 100–1000nm height and 1μm width were obtained on specimens by successive anodizing, probe processing, and electrophoretic deposition. [Copyright &y& Elsevier]

An offline measurement of surface ripples propagation has been proposed using sequential ion beam irradiation approach. First, the ripple patterns were grown on Si (100) using 100 keV Ar+ at a fluence of 9 × 1017 ions/cm2 and then subsequent second stage irradiation was performed on partially masked rippled surface to study the ripple's propagation and surface erosion. Offline atomic force microscopy (AFM) study shows that with increase in fluence from 3 × 1017 ions/cm2 to 7 × 1017 ions/cm2, in second stage irradiation, the ripples are found to propagate along the projection of the ion beam's incident direction onto the surface. This observation of ripples propagation contradicts several existing models for ion-beam-induced ripple development. Furthermore, surface erosion rate due to sputtering was measured using stylus profilometer. A prediction of relation " v ~0.75 v o " between ripple's propagation velocity (v) and surface erosion rate (v o) shows the importance of Navier-Stokes viscous flow in near surface layer for the evolution of ripple patterns under ion beam irradiation (IBI). • A new approach of measuring ripples velocity in offline mode. • First time measurement of surface erosion rate using offline atomic force microscopy and stylus profilometer. • Correlation between ripples propagation velocity and surface erosion rate. • Experimental evidence of Navier stokes flow in ripples propagation. [ABSTRACT FROM AUTHOR]