While investigating isolated or agglomerates of treated Vaccinia virus intracellular mature (IMV) particles in atomic force microscopy (AFM) equipment we noticed that in some occasions the enveloped particles had been totally disrupted, with the interior being spread around. We have also observed in these samples what appear to be some rather intriguing viral surface interactions. Instead of showing a clear division between individual virions the particles seem to be continuous at the interfaces that show coalescence. In order to understand what was happening we focused our attention on the analysis of the images of the interface between virions particles, trying to find out what was the explanation for such type of particle surface interaction and in which conditions it would take place.

Atomic force microscopy (AFM) is a powerful tool for direct visualization of supported biological membranes [1]. Moreover, in-situ AFM measurements permit investigations of biological phenomena in real time and in physiological environments. In a previous work, we have studied the morphology and stability of supported phospholipid layers prepared by solution spreading (casting) on mica [2]. The images were acquired in the contact or contact-intermittent modes and the samples analyzed ex-situ just after solvent evaporation and after a hydration step, and in-situ with immersion in a buffer solution. Contact-mode imaging is less suitable for soft or weakly attached materials, since the tip can often scrape or drag the membranes during scanning, a disadvantage that can be overcome by applying intermittent methods. However, studies have also demonstrated that by adjusting the operative force it is possible to use contact-mode to obtain AFM images of soft phospholipids layers [3]. In the present work, we applied successfully in-situ AFM contact-mode to characterize phospholipid layers of 1,2-dimyristoyl-sn-glycero-3-phosphatitidylcholine (DMPC) and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC), as well as a binary mixture of these phospholipids. The supported membranes were prepared on mica substrates by vesicle fusion method.

The adsorption of polysaccharides onto solid substrates provides an environment for the immobilization of biomolecules [1] giving rise to conditions for the development of biosensors [2] and kits for immunoassays. One can find in the literature reports about the adhesion of proteins on cellulose ester membranes [3]. However, studies about the formation of cellulose ester ultrathin films have been seldom reported. Cellulose esters are nontoxic materials largely used as coating layers, fibers, inks and films.

In the last decades several investigations have been conducted with the objective of studying the microstructural characteristics and mechanical properties in low carbon microalloyed steel [1,2]. These steels contain a polyphase microstructure, with complex mixture of bainite, MA constituent (martensite-austenite residual), pearlite, ferrite and martensite. They are often used in the automobile industry, in the production pipelines for the transport of gas and oil in areas of sub-zero temperature and in the naval ship construction, because they possess high strength, high toughness at low temperature and good weldability.

Scanning probe microscopy (SPM) is unique among the imaging techniques in which it provides three-dimensional (3-D) real-space images and among surface analysis techniques in which it allows spatially localized measurements of structure and properties. Under optimum conditions, subatomic spatial resolution is achieved. The development given has not been only because of its ability to obtain topographic and structural images of the surface at micro and nano scale, but also for the possibility of performing analysis of superficial properties such as local adhesion properties, chemical heterogeneity, and local mechanical properties [1]. The SPM has different variations depending on the interaction between the tip and the sample surface, such as AFM, which has the ability of showing topographic characteristics at atomic scale, LFM, which measures local friction differences, FMM and PDM that measure differences of local elasticity. The instrument counts with the spectroscopy mode and with this it is possible to obtain Force — distance (F-d) curves that give information about the local elastic properties of the sample surface. In this work, TiN and ZrN thin films grown by the PAPVD by pulsed arc technique were studied, using the AFM, LFM, FMM, PDM and spectroscopy F vs. d techniques.

Silicon based devices are expected to achieve the limit of possible downscaling in 10 to 15 years. Thus, the search of new materials to construct smaller, faster and more energy efficient devices has been a very active research area. Carbon nanotubes (CNTs) are very good candidates to construct nanoelectronic and nanophotonic devices [1,2,3] due to unique physical properties, such as its metallic or semiconducting characteristics depending only its diameter and chirality [4,5] and capability of caring high current densities (up to 1010A/cm2). In this work we develop nanofabrication techniques of single-walled carbon nanotubes (SWNTs) based devices using a combination of electron beam and optical lithography with Atomic Force Microscopy (AFM). We used both CVD-grown nanotubes [6] and HipCO-NTs [7] suspended on aqueous solution and deposited on the substrate. Atomic Force Microscopy (AFM) in tapping mode (Multimode Nanoscope IV, Digital Instruments) was used to CVD sample characterization, study of CNT deposition and to localize and index the nanotubes on substrate using lithography patterns as references, making possible to selectively construct metallic contacts on the CNTs.

Stable and defect-free films are required for many technological applications, while controlled dewetting processes are important for producing thin film microstructuring for microelectronics, optical devices and biochip technology. In this work, we study the dewetting features formed by drying an aqueous solution of a charged polymer deposited on a mica substrate. A rich variety of morphologies can be formed, including holes, polygonal networks, droplets and elongated structures. The dewetting behavior depends on film thickness and on the charge density on the polymer that can be controlled by surfactant addition. The various nanoscale morphological patterns that are formed may be applied as a potential method for surface nanostructuring.

The use of ultrathin polymer films as sensoactive layers in chemical sensors has received great interest in recent years due to many advantages such as the wide choice of polymeric system (polymer types and/or combination, dopants in conducting polymers, etc), and the possibility of tailoring the properties of these films in terms of sensitivity and selectivity by an efficient control of the film formation process [1]. Among the techniques used for ultrathin films formation, self-assembly (SA) offers several advantages since the substrate can take any form and size, deposition time is independent of the substrate area, there are no requirements for additional equipments and/or clean rooms, and a large quantity of materials can be assembled into thin films [2-8].

Tin oxide (TO) or fluorine doped tin oxide (FTO) has been frequently used as a transparent electrode in our organic opto-electronic devices [1-3]. In general, these devices are fabricated in a sandwich structure where an organic thin layer (approx. 100nm thick) stays between two conducting electrodes, TO or FTO and Al. Due to higher conductivity FTO is normally our choice. The morphology of the electrodes influences the morphology of the organic layer, mainly when the deposition of the organic layer is done electrochemically.

Polymer blends are of increasing interest in the field of surface technology because they can be used to change or tailor the properties of surfaces for special application. In most cases not only the chemical nature of the components is important for the physical properties of the blend but also the components distribution on the blend surface. This distribution is strongly dependent on the adsorption energy of the polymers onto the substrate. According to the Flory-Huggins theory, the criterion for polymer miscibility in blends is that the average interaction parameter for a binary mixture of polymers, 12, must be less than a critical value cri, which is calculated from weight-average degrees of polymerization of the two polymers [1]. This parameter also describes the difference of the interaction energies between similar and different monomers. During the spin coating process the system tries to reach a state of low energy, indicating that the substrate surface and the vapor phase influence the wetting and dewetting of the substrate by the resulting polymer films. However, one should notice that spin-coated film structure may not correspond to the equilibrium one due to the rapid solvent evaporation during the spin coating process and to solvent effects [2].

Thin film morphology and electrical resistivity play an important role in modern technologies. In particular, subcomponents fabricated by Ti play an increasing role in microelectronic device technology as well as in the biomedical area [1-2]. Here the influence of substrate temperature (during deposition) and film thickness on the surface morphology and electrical resistivity of polycrystalline Ti and Zr thin films have been investigated.

The possibility of analyzing surfaces at the nanoscale provided by atomic force microscopy [1] (AFM) has been explored for various materials, including polymers [2], biological materials [3] and clays [4]. Further uses of AFMs involved nanomanipulation [5] and measurements of interaction forces, where the latter has been referred to as atomic force spectroscopy (AFS) [6]. Measurements of surface-surface interactions at the nanoscale are important because many materials have their properties changed at this range [7]. For samples in air, the interactions with the tip are a superimposition of van der Waals, electrostatic and capillary forces. A number of surface features can now be monitored with AFS, such as adsorption processes and contamination from the environment. Many implications exist for soil sciences and other areas, because quantitative knowledge of particle adhesion is vital for understanding technological processes, including particle aggregation in mineral processing, quality of ceramics and adhesives. In this paper, we employ AFS to measure adhesion (pull-off force) between the AFM tip and two types of substrate. Adhesion maps are used to illustrate sample regions that had been contaminated with organic compounds.

The incorporation of soft rubber into a thermoplastic matrix can lead to tough blends. Generally, such binary blends are immiscible and exhibit poor mechanical properties caused by the unfavorable interactions between the two phases. Thus, there is an enormous interest in polymer blend compatibility to improve the properties of the polymer blends by the addition of an appropriate compatibilizer [1,2].

The need of techniques for determining the mechanical properties of thin films, e.g. hardness coatings on ion beam treated surfaces has prompted a study of the microindentation hardness technique. The present interest is driven to a good understanding of the adhesion, friction, wear, and indentation processes. In most of the solid-solid interfaces of technological relevance, it occurs contact in many asperities, and this is why the study of fundamental properties of micro-mechanic and tribology of surfaces and interfaces is very important. The recent developments of different microscopic techniques based on tips and force surface devices (i.e. AFM, FM, LFM) allowed investigations of interfacial problems with high resolution and have led to the nanoscale regime the mechanical properties study for a wide spectrum of materials. In this work a method for Young's modulus determination of hard coatings multilayers of TiN/ZrN is evaluated. This method is based on AFM and spectroscopy-force modes [1-2].

Molecular level organization has been a subject of great relevance in supramolecular chemistry and nanotechnology. Supramolecular chemists count on the ability of molecules to form several kinds of organization, allowing the development of nanoscaled devices. In this way, the scanning probe microscopy provides a great tool for characterization, manipulation and interfacing such devices [1]. Regarding the ruthenium complexes [Ru(bpy)2Cl(BPEB)](PF6) and {[Ru(bpy)2Cl]2(BPEB)}(PF6)2, where bpy = 2,2'-bipyridine, the presence of the BPEB (1,4-bis[4-pyridyl)ethenyl]benzene) ligand has an important role as a recognition site for van der Waals interactions (Figure 1). On the other hand, cyclodextrins are macrocyclic molecules bearing a hydrophobic cavity that can support several types of guest molecules [2-3]. In this work we are showing the influence of the recognition site of the BPEB ligand and the formation of an inclusion compound in the patterning structures of films deposited over mica substrates, by SFM microscopy.

Although the development of conducting polymers is very recent, such materials have already been shown to possess a number of useful properties that may be exploited in a range of technological applications. In particular, the representative conducting polymer polypyrrole (PPy) has been the subject of considerable research interest owing to its facile polymerisation and practical application in products as diverse as gas sensors [1], electrochromic devices [2] and battery / capacitor components [3].

Cold rolled sheets of AISI 430 ferritic stainless steel have been widely used in kitchen utensils, ornamental articles, among other products due to their corrosion resistance and good formability. However, a localized increase of the surface roughness, known as ridging, develops during ferritic stainless steel forming [1]. The ridging is caused by anisotropic plastic flow of the material containing alternated bands of different crystallographic textures. These bands, or grain colonies, are formed during hot rolling fabrication step. During this step, the deformed grains can undergo dynamic recrystallization and/or recovery. In the regions where recovery takes place these texture bands are formed. In order to study ridging, it is necessary to identify the recovered regions (regions containing sub grains with nearly the same crystal orientation) and recrystallized regions (regions containing grains with different crystal orientations). Two well established techniques are applied to the characterization of recrystallized and recovered grains: the optical microscopy with polarized light, normally done in samples prepared with colored etching, and the electron backscatter diffraction (EBSD). In this work, atomic force microscopy (AFM) and magnetic force microscopy (MFM) were used to study the recrystallization and the recovery of the deformed specimens.

In this study, the surface morphology of electrodeposited Ni on single crystal GaAs (001) was investigated by atomic force microscopy (AFM). The images show granular deposits with stepped contours typical of single-crystalline grains. The correlation length correlates very well with the size of the grains, indicating that the layers grow as columns with diameter increasing with thickness. This growth mechanism is observed for layers with thicknesses in the range of 10 to 500 nm at a deposition rate of ~0.5 nm/s.

The controlled construction of nanostructures on solid surfaces for technological applications depends primarily on a deep understanding of the physical chemistry of the interface. Several methods have been devised to grow metallic nanostructures on solid surfaces, notably physical vapor deposition and electrodeposition. The electrochemical method led to the creation of a very promising technology called Electrochemical Step Edge Decoration (ESED) by the Penner group in Irvine, Ca. In this method, metallic nano and mesowires are built through electrochemical deposition on the step edges of the basal plane of Highly Oriented Pyrolytic Graphite (HOPG) [1]. The proposed growth mechanism is based on the Terrace-Ledge-Kink (TLK) model [2], in which the foreign adatoms nucleate the electrochemically induced growth of nanoparticles in the lower plane of step edges. White and collaborators [3], while studying the stability of gold nanoparticles electrodeposited on HOPG, noticed the preferential nucleation on the upper plane of step edges in stark opposition to the TLK model. They proposed that this preferential deposition is associated with a slippage of the atomic layer near the edge. This proposition indicates that the surface in the upper plane near the edge will present a decrease in the atomic distance in the plane, disrupting the registry with the underlying plane. To further assess this proposition we have devised another experimental approach where, instead of electrodepositing foreign adatoms for nucleation and growth, we deposited fully formed silver nanoparticles on HOPG through a Self Assembly mechanism and studied its spatial distribution. Through this approach, we intend to study the surface mobility of nanoparticles, as opposed to atomic species as studied in electrochemical deposition.

Surface chemistry and topography of materials are generally preponderant factors in a series of material properties, such as adhesion, wettability, friction and optical properties [1]. Wettability of films, for example, can be altered significantly by modifying its surface roughness and also by incorporating functional groups. Plasma treatment is a powerful and versatile way to modify surface properties of amorphous nitrogen-incorporated carbon thin films (a-C:H(N)) and obtain materials with improved properties, once it is possible to modify the surfaces in a controlled way by specific settings of plasma conditions. [2 - 4]