Surface properties INDEX

The applications of fluorinated telomers or fluoro oligomers are linked to their exceptional properties [1] excellent thermostability,remarkable surface properties, low refractive indexes, low dielectric constants and very high chemical stabilities. 

In recent years, cyclic polymers (also referred to as polymer rings or macrocycles) became easier to prepare. By a number of different approaches and advances in cyclization techniques, a wide range of novel cyclic polymers have been prepared in good yields [10]. In contrast to linear polymers, cyclic polymers are topologically distinct species, and all monomer units of cyclic polymers are chemically and physically equivalent. This equivalence is due to the fact that their properties are not affected by the nature of the end groups, since cyclic polymers have no chain ends. They include the radius of gyration, intrinsic viscosity, translational friction coefficient, critical solution temperature, refractive index, density, dipole moment, glass transition temperature, and surface property [11]. 

The examination of surface properties of three low-index surfaces of Pt3Ni(/j/ 0 has also been pursued recently by a combination of low-energy electron diffraction (FEED) and LEIS [23]. As summarized in Fig. 3.2, the PtjNi(l 11) surface exhibits a (1 X 1) FEED pattern (Fig. 3.2d) the atomically less dense PtjNi(lOO) surface shows a clear (1 x 5) reconstruction pattern (the so-called hex phase) in both the... 

Recently systematic studies of the surface properties of glass and other insulators have been made after bombardment with ions in the 40 to 100 keV range. Refractive index modifications were observed which are caused by phase changes, micropo-... 

Kilduff, J.E., Belfort, G., Nayak, A. and Zhou, M. 2004. Progress report Graft polymerization as a route to control nanofiltration membrane surface properties to manage EPA candidate contaminants and reduce NOM fouling. http //c ub.epa.gov/ncerabstracts/index.cfm/ fuseaction/display.abstractDetail/abstract/6236/report/2004 (accessed April 23, 2009). 

Fluorinated poly(methacrylates) or poly(acrylates), rich in trifluoromethyl groups, exhibit superior performance of chemical inertness, excellent weatherability, low refractive index, lower dielectric constant, and special surface properties [14,61]. Poly(2,2,2-trifluoroethyl methacrylate), poly(MATRIF), is an important class of such materials. It has been extensively used in high performance coatings [17], photoelectric communications, and microelectronics [62]. Poly(MATRIF) is easily produced by free radical polymerization using bulk, solution, and emulsion polymerization methods [63]. Structural characterization of NMR of poly(MATRIF) prepared by radical and anionic polymerization has been studied. Syndiotactic structure was obtained by radical initiator in contrast to an isotactic structure achieved by anionic polymerization [64]. 

The specific surface area and pore structure are the most basic macroscopic physical properties of solid catalysts. Pore and surface are the reactive rooms of heterogeneous catalytic reactions, and the amount of surface area directly influences the level of catalytic activity. If the surface properties of catalyst are uniform, then their activity is directly proportional to their surface area. Catalytic reactions are generally influenced by the diffusion under industrial conditions, and the activity, selectivity and lifetime and almost all properties of catalyst are related to these two macroscopic physical properties. Although the activity for most catalysts is not proportional to their surface area, the surface area is still a visual physical quantity to evaluate catalyst performance, and sometimes acts as a control index of preparation. 

As can be inferred from the refractive index profiles, the porosity profiles in films may be quite complex, depending on the coating sol structure and its condensation as well the substrate surface properties and its pretreatment. If highly condensed sols are used the profiles of porosity increase from the minimum values at the substrate surface to level out with a rise in distance from the substrate surface. 

---