Topography films

Besides phase identification XRD is also widely used for strain and particle size determination in thin films. Both produce peak broadenings, but they are distinguishable. Compared to TEM, XRD has poor area resolution capability, although by using synchrotron radiation beam diameters of a few pm can be obtained. Defect topography in epitaxial films can be determined at this resolution. 

Fig. 2. Maps (2x2 pm) of. sample topography (height variation) and pull-off adhesive force for a Langmuir-Blodgett film on mica consisting of a I I mixture of palmitic (Cl6) and lignoceric (C24) fatty acids [46].

Figure 6-14. Average domain size vs. inverse deposition temperature Tor different film thicknesses. Error bars represent the mean absolute error and straight lines the best lit for each film thickness. Doited line is the locus of the transition from grains to lamellae. Data for 50-nm films are estimated from the correlation length of the topography fluctuations. Adapted from Ref. [501.

Fig. 16—Topography of star-shaped Cgo-Pst L-B films (scan range 2 y m), (a) monolayer, (b) four layers.

AFM is used in the surface analysis. Figure 16 is the AFM topography of the monolayer and the multilayer L-B films. It shows that the monolayer L-B film is well packed and highly ordered on the mica surface. The surface of the monolayer film (shown in Fig. 16(a)) has a higher packing density than that of the four-layer L-B film (shown in Fig. 16(b)). This is because the molecules form the different structures in the monolayer film from those in four-layer... 

Fig. 21 —Friction force and topography images of the L-B films of Cgo-Pst hyperbranched polymer under load 2 nN using AFM/FFM, image (a) and (b) are friction force images and image (c) is the topography.

Fig. 26—AFM topography of monolayer L-B film for two different areas [(a) point A, (b) point B] (a) scan range 2 /i.m (b) scan range 1 /u.m.

Though most experiments get similar results, some special results are also obtained in the measurements, e.g., the result shown in Fig. 31. The surface roughness of the point in the experiments of Fig. 31 is a little larger than for most other parts of the film. This shows that the topography of the L-B film plays an important role in the friction properties obtained by using FFM measurement. Therefore having the well-prepared and highly ordered L-B film is one important factor for friction measurements. However, results like the one shown in Fig. 31 can still be accepted. Because there are so many factors that can affect the experiment results at the nanometer scale, more experiments need to be done. 

It has been shown that surface-modihed C5Q-Pst polymer was synthesized and was transferred onto mica chips by using the vertical dipping method of L-B film techniques. Though the surface was scanned many times, only a small amount of transfer could be found on the surface of the L-B Hlms. L-B films of C5Q-Pst polymer, even with only one layer, showed good microtribological performance. The topography and the order of the hlms are the most important factors influencing the microscale friction and wear. 

The Influence of the PFAM Concentration on the Film Thickness, the Water Contact Angle, and the Surface Topography... 

It can be concluded that the concentrations of the PFAM solution is an important factor for the PFAM film formed on the slider surface to affect the stiction and friction in the CSS tests. If the concentration is controlled around 500 ppm, an ideal surface topography, good hydrophobic nature, a preferred film thickness, and better frictional and anti-wear properties can be obtained. 

Formation from Template Surfaces Recently, a new method for the preparation of LUV was reported by Lasic et al. (1988). The method is based on a simple procedure which leads to the formation of homogeneous populations of LUV with a diameter of around L vim. Upon addition of solvent to a dry phospholipid film deposited on a template surface, vesicles are formed instantly without any chemical or physical treatment. The formation of multilamellar structures is prevented by inducing a surface charge on the bilayers. The size of the vesicles is controlled by the topography of the template surface on which the phospholipid film was deposited (Lasic, 1988). 

The chain architecture and chemical structure could be modified by SCVCP leading to a facile, one-pot synthesis of surface-grafted branched polymers. The copolymerization gave an intermediate surface topography and film thickness between the polymer protrusions obtained from SCVP of an AB inimer and the polymer brushes obtained by ATRP of a conventional monomer. The difference in the Br content at the surface between hyperbranched, branched, and linear polymers was confirmed by XPS, suggesting the feasibility to control the surface chemical functionality. The principal result of the works is a demonstration of utility of the surface-initiated SCVP via ATRP to prepare surface-grafted hyperbranched and branched polymers with characteristic architecture and topography. 

As we have seen in the previous chapter, the apparent topography and corrugation of thin oxide films as imaged by STM may vary drastically as a function of the sample bias. This will of course play an important role in the determination of cluster sizes with STM, which will be discussed in the following section. The determination of the size of the metallic nanoparticles on oxide films is a crucial issue in the investigation of model catalysts since the reactivity of the particles may be closely related to their size. Therefore, the investigation of reactions on model catalysts calls for a precise determination of the particle size. If the sizes of the metal particles on an oxidic support are measured by STM, two different effects, which distort the size measurement, have to be taken into account. 

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