Interphase analysis

Multiplex ampMcation of several STR loci with sizing by fluorescent detection Interphase analysis of X and Y... 

This route to interphase analysis may also be described as the thin-film approach, inasmuch as the basic principle involves the deposition of extremely thin layers (< 2 nm) of the mobile phase onto a substrate. In the work described here the mobile phase is the organic component of the system, but the same approach is applicable to studies of the metallization of polymer substrates. 

In the case of metallic adsorbates (metal deposits, underpotentially deposited upd-layers, catalytically active metal deposits), the type of coordination to surface sites (one-, two- or three-fold) and the distance to these sites may be of interest. Vice versa the same type of data may be of importance in the case of adsorbed ions on metal electrodes or about the atomic environment of a given atom/ion in an interphase. Analysis of the fine structure of X-ray absorption (EXAFS, XANES) close to the X-ray absorption edge of the species (atom) of interest will yield this data provided the sample can be prepared in a very thin layer in order to exclude unwanted bulk interference. Otherwise the experiment can be done in reflection (SEXAFS). Information about the distance between the atom of interest and its first and sometimes even second shell of surrounding species can be derived from the spectra [95]. Availability of a suitable light source, generally a synchrotron (for details see p. 15), is an experimental prerequisite. The method has been applied in studies of passive and corrosion layers on various metals [96-102] and of molecular and ionic adsorbates on single crystal surfaces [103]. 

Adhesion involves a detailed understanding of polymer synthesis and characterization, mechanics, and surfaces. This chapter reviews surface analysis and interphase analysis emphasizing polymer/metal systems. The interphase is a thin region between the bulk adherend and the bulk adhesive, as depicted in Figure 1. A surface oxide, either native or one produced by pretreatment, is present on most metal adherends. A primer is often applied in a production process after pretreatment and before the application of an adhesive. Typical thicknesses for the oxide are 0.003-0.4 jLm, for the primer 4 xm (0.16 mil), and for the adhesive 40 fim (1.6 mil). The interphase region is expected to have mechanical properties different from either the adherend or the adhesive. Measurement of these properties is important in understanding adhesion, for example, poorly durable bonds are often a consequence of poor interphase properties.0 2) Thus, one of the frontier areas in adhesion science today is determining interphase properties. 

Depth concentration measurement is an important application of surface analytical methods. Examples are depth distribution of additives in plastics, or interface analysis where polymers are in contact with metals or ceramics. All surface methods with a good depth resolution (XPS, AES, SIMS) are suitable for depth or profile measurements. Complete multilayer coating systems require analytical methods that are applicable to small sample sizes and low concentrations. Techniques for obtaining chemical composition and component distribution depth profiles for automotive coating systems, both in-plane (or slab) microtomy and cross-section microtomy, include /xETIR, /xRS, ToE-SIMS, optical microscopy, TEM, as well as solvent extraction followed by HPLC, as illustrated by Adamsons et al. [5]. Surface and interface/interphase analysis can now be done routinely on both simple monolayer coatings and complex multicomponent, multilayered... 

The plateau of the adsorption isotherm indicates the concentration(s) at which all adsorption sites for the adsorbing species are occupied, in surface chemistry terms the fractional surface coverage of the substrate by the adsorbate is unity. Such a specimen provides an ideal opportunity to probe the interfecial chemistry of adhesion directly using what is sometimes referred to as the thin film approach. As the layer of organic material, such as adhesive, is very thin (as a result of monolayer coverage) the contribution of interfacial chemistry at the interface will be maximized in the resultant XPS or ToF-SIMS spectrum. For this reason, the construction of adsorption isotherms is often used as a precursor to direct interphase analysis in this manner. 

Static mixing of immiscible Hquids can provide exceUent enhancement of the interphase area for increasing mass-transfer rate. The drop size distribution is relatively narrow compared to agitated tanks. Three forces are known to influence the formation of drops in a static mixer shear stress, surface tension, and viscous stress in the dispersed phase. Dimensional analysis shows that the drop size of the dispersed phase is controUed by the Weber number. The average drop size, in a Kenics mixer is a function of Weber number We = df /a, and the ratio of dispersed to continuous-phase viscosities (Eig. 32). 

It was concluded that the filler partition and the contribution of the interphase thickness in mbber blends can be quantitatively estimated by dynamic mechanical analysis and good fitting results can be obtained by using modified spline fit functions. The volume fraction and thickness of the interphase decrease in accordance with the intensity of intermolecular interaction. 

Jean-Claude Charpentier, Mass-Transfer Rates in Gas-Liquid Absorbers and Reactors Dee H. Barker and C. R. Mitra, The Indian Chemical Industry-lts Development and Needs Lawrence L. Tavlarides and Michael Stamatoudis, The Analysis of Interphase Reactions and Mass Transfer in Liquid-Liquid Dispersions... 

The interfacial zone is by definition the region between the crystallite basal surface and the beginning of isotropy. Due to the conformationally diffuse nature of this region, quantitative contents of the interphase are most often determined by indirect measures. For example, they have been computed as a balance from one of the sum of the fractional contents of pure crystalline and amorphous regions. The analysis of the internal modes region of the Raman spectrum of polyethylene, as detailed in the previous section of this chapter, was used to quantify the content of the interphase region (ab). 

A factor analysis of the Raman spectra of a set of linear polyethylenes identified the existence of a third component in addition to the pure crystalline and pure amorphous components [78]. The characteristics of the Raman spectrum of the interphase were very similar to that of the crystalline spectrum indicating that the interphase retains a significant degree of order. Using the Raman method, the content of interphase in linear polyethylenes was found to increase with molecular weight [74—76,78]. For molecular weights below... 

By virtue of the conditions xi+X2 = 1>Xi+X2 = 1, only one of two equations (Eq. 98) (e.g. the first one) is independent. Analytical integration of this equation results in explicit expression connecting monomer composition jc with conversion p. This expression in conjunction with formula (Eq. 99) describes the dependence of the instantaneous copolymer composition X on conversion. The analysis of the results achieved revealed [74] that the mode of the drift with conversion of compositions x and X differs from that occurring in the processes of homophase copolymerization. It was found that at any values of parameters p, p2 and initial monomer composition x° both vectors, x and X, will tend with the growth of p to common limit x = X. In traditional copolymerization, systems also exist in which the instantaneous composition of a copolymer coincides with that of the monomer mixture. Such a composition, x =X, is known as the azeotrop . Its values, controlled by parameters of the model, are defined for homophase (a) [1,86] and interphase (b) copolymerization as follows... 

Conventional Chromosome Analysis versus High-Resolution Interphase Cytogenetics... 

A2. Anastasi. J., Interphase cytogenetic analysis in the diagnosis and study of neoplastic disorders. Am. J. Clin. Pathol. 95 Suppl. 1, S22-S28 (1991). 

Fig. 2. Exchange of histones Hl.l and H2B from chromatin in interphase cells by analysis with fluorescence recovery after photobleaching (FRAP). Half of a nucleus of an SK-N cell expressing GFP-Hl.l was bleached (upper panel), and the recovery monitored over the times shown. Similarly, a region of a nucleus of an SK-N cell stably expressing H2B-CFP was bleached (lower panel), and the recovery monitored over the times shown. Whereas unbleached HI molecules move into the bleached region after a few minutes, the H2B histones are much less mobile, since the bleached region shows no recovery (from Ref [23]). Scale bar 5 pm.

This breakdown of electroneutrality in the solution, in the vicinity of the electrode, is a fundamental characteristic of the double-layer region. The next question is how far this double-layer region (interphase) extends out from the electrode into the solution. This question can be answered on the basis of analysis of the potential variation (distribution) in the double layer. 

Thomason, J.L. (1990). Investigation of composite interphase using dynamic mechanical analysis artifacts and reality. Polym. Composites 11. 105-113. 

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