Nanomanipulation using Atomic Force Microscope (AFM) is one of the new emerging approaches to manufacturing in nano scale. Wide spread applications of nanorods and lack of real time imaging in nanotechnology cause necessity of process modelling. This article presents a new dynamic model for flexible nanorods on elastic substrate. This model is presented a nine steps strategy to push nanorod and considered the three basic nano forces

van der Waals, friction and contact force to quantitative analysis of effective parameters. Dynamic analysis of nanorod pushing considering depression on elastic substrate, indention between tip-nanorod and deflection along straight path is presented. Using beam on elastic substrate assumption complete model up to now for nanorod manipulation is obtained. This model is verified by available (theoretical and experimental) results. A polystyrene nanorod is simulated and snap in /pull out distances, critical force and time, maximum deflection and safety factor of process are obtained. Also, it is determined that dynamic mode of micro and nanorods is different. Despite of rolling mode being dominant in micro rod manipulation, sliding mode is observed to be dominant dynamic mode in the pushing of nanorods. Our model can be used in mechanical behaviours of nanorod.

Keywords:
Nanomanipulation, Atomic Force Microscope (AFM), Pushing Strategy, Nanorod on Elastic Substrate, JKR Contact Theory.

Different types of polymer/clay nanocomposites were prepared and evaluated for their application as hard and anti-scratch coating materials. Photo-curable nanocomposites based on 2,2-bis[4-(methacryloxypropoxy)-phenyl]propane (Bis-GMA ) and tri(ethylene glycol)dimethacrylate (TEGDMA ) (50/50 wt.%) were prepared using three types of clays at different loading levels. The adhesion properties and scratch resististivity of the coatings on polymethymethacrylate slabs were investigated. The results were correlated with the clay dispersion state determined by transmission electron microscopy, X-ray diffraction and the surface morphology by atomic force microscopy. It was concluded that exfoliation or intercalation plays an important role primarily on the surface roughness which in turn affects adhesion by changing the characteristics of the coating–substrate interface. The highest scratch resistivity with appropriate adhesion quality was obtained for sample containing 1 wt.% of more compatible clay, Cloisite® 30B in the nanocomposite resin mixture.

Keywords:
Nanocomposite

Coating
Anti Scratch
Poly(methylmethacrylate)
Bis-GMA
TEGDMA

We investigated vapour-phase-epitaxy grown ZnO NWs on a Si substrate by SEM. SEM investigations show that there are single NWs and ensembles of NWs, among which we found straight and bend, perfect (with regular facets and smooth surfaces) and non-perfect (with irregular facets, not smooth surfaces, variable width, damages and particles) NWs, as well as NWs with clean surfaces and surfaces with the dark spots and features. After FIB polishing we found that every NW has a clean homogeneous surface, which allow us to conclude that all those dark spots and surface features of the NWs really are just surface features. The FIB milling gives information of the deeper interior of the NWs, i.e. buried structures within the NWs and whether those structures are propagating within the NWs. But also here we found that there are no buried structures inside the NWs and the dark spots and features are not propagating within the NWs, which leads to the result that the NWs are totally homogeneous. The hexagonal facets of the NWs were observed on SEM images, which emphasizes the good crystalline quality of the NWs. The sizes of the NWs were determined: the length is about 2-24 µm, and the width and height are about 200-500 nm.

Keywords:
Scanning Electron Microscope, NANOWIRES on Si(111), FIB milling

A series of freeze-thawed polyvinyl alcohol nanocomposite hydrogels were prepared using various loading levels (0-15 wt.%) of hydrophilic natural Na-montmorillonite nanoclay. The morphology of nanocomposite hydrogels, their dehydration kinetics at different temperatures and the effect of Na-montmorillonite on the gelation process were investigated. The results showed a partially exfoliated morphology for the prepared nanocomposite hydrogels. Also, by increasing the amount of nanoclay incorporated into the specimens, the gel fraction values of nanocomposite hydrogels were increased. According to the dehydration tests, the dehydration rates of nanocomposite hydrogels exhibited an inverse dependency on the nanoclay loading level and a direct dependency on the dehydration temperature. Finally, it was concluded that the dehydration mechanism of all specimens prepared is non-Fickian at 20 ◦C, while it is Fickian at 37 and 55◦C.

Keywords:
Dehydration kinetics

Nanocomposite hydrogel
Polyvinyl alcohol
Na-montmorillonite.

A nanocomposite coating based on Glycidioxypropyltrimethoxysilane and Aminoethylaminopropyltrimethoxysilane was prepared using silica nano particles in a sol-gel process by the addition of silica suspension. The good level of adhesion was attributed to the formation of Si-O-Si bonds between the coating and the substrate. Moreover, another factor in improving adhesion was linked to the tendency of silica particles to form aggregates in the continuous phase. This morphology enhances the organic phase mobility of the coating which leads to flexibility of the coating in stress support and improving adhesion. In order to evaluate the hypothesis, the relaxation properties of this coating were compared with those of a coating synthesized by in situ polymerization of tetramethoxysilane by means of Dynamic mechanical thermal analysis. The results proved the validity of the theory that silica particles of the coating prepared with silica suspension tend to form aggregates and produce particle-matrix morphology which lets the organic phase to find further mobility. Scanning Electron Microscopy was employed to monitor the surface of the coating. Atomic Force Microscopic technique was used to monitor the surface roughness of the coating. Transmission Electron Microscopy showed that the dimension of silica particles remains at nano scale.

Keywords:
Coating, Nanocomposite, Silica suspension, Morphology