Surface morphology, degradation

Another kind of treatment, to which substrates are often subjected prior to the growth, is the plasma cleaning procedure. It appears, however, that this treatment is not always suitable for PSC substrates, since it causes both surface morphology degradation and coarsening of the... 

The effect of °Co y-ray irradiation on the mechanical properties, surface morphology, and fractography of blends of plasticized PVC and thermoplastic copolyester elastomer, Hytrel (E.I. Du Pont de Nemours Company, Inc., Wilmington, Delaware), have been studied by Thomas et al. [445]. Radiation has two major effects on the blend cross-linking of the Hytrel phase and degradation of PVC phase. Both effects are found more prominent at higher radiation dose. 

Having said this, it was felt therefore that there is a need for a book addressing analysis and characterisation of polymers from the point of view of what we wish to call the primary analytical question. Many excellent textbooks and reference works exist which address one or more individual analytical techniques, see, for example, references [1-10]. These books form the basis of the knowledge of the technique expert. They also contain many excellent and varied examples on successful applications of analytical techniques to polymer analysis and characterisation. There are also books which address the multitude of analytical techniques applied in polymer analysis, see, for example, references [11-24], However, a synthetic chemist may wish to know the constitution of his/her polymer chain, a material scientist may want to find out the reasons why a fabricated sample had failed. What technique is best or optimal to study chain constitution will depend on the situation. Polymer failure may result from morphological features, which needs to be avoided, a contaminant, a surface property degradation, etc. When a sample has been processed, e.g., a film blown, molecular orientation may be the key parameter to be studied. A formulation scientist may wish to know why an additive from a different supplier performs differently. It is from such points of view that polymer analysis and characterisation is addressed in this book. 

The photochemical properties of titania surfaces are of interest for several reasons. They determine the stability of pigmented paint systems [76], the rate at which pollutants can be degraded in systems designed to purify air and water [77], and are the root cause of poorly understood phenomena such as water photolysis [78] and super hydrophilicity [79]. Using thin rutile epilayers with five low index orientations, it has been shown that the relative rates of photochemical reactions catalyzed by titania depend on the surface orientation [80]. In this chapter, experiments used to map the complete orientation dependence of the relative photochemical reactivity of TiO are described [81-83]. In this case, the relevant reactions are carried out at room temperature and this gives us the opportunity to fix both the surface morphological structure and stoichiometry. For the reactions described here, all of the surfaces were... 

Unfortunately, the electrodeposition of metals summarized in Table 4 is accompanied by increased HTSC degradation under cathodic polarization [53, 55]. In nonaqueous media, electrocrystallization processes can be inhibited due to the peculiarities of the intermediate Cu+ species solvation [286]. Moreover, the surface morphology of deposits can be adversely affected by the formation of dendrites this can be overcome by the addition of a brightening agent [497]. 

Surface nano-morphology changes of photoreactive molecular crystals are an attractive area of research, because the phenomena could potentially be applied to photodriven nanometer-scale devices and provide important information on crystal-line-state reaction mechanisms and dynamics [2a, 21]. As described in Section 25.3.2, the single crystal of lEt, in which the CpEt rings have no reorientation freedom in the crystal, tends to collapse and degrade as the reaction proceeds. This observation for the crystal of lEt can be explained by the local stress induced by the photoreaction that is not suitably released by the crystal lattice. In such a crystal, does the surface morphology of the crystal change ... 

As seen in Fig. 10 the steel surface of the wheel is modified by PTFE-PA material. The surface morphology is the same as the disc surface (used the PTFE-PA-6 test specimen). The examined PTFE PA-6 material consisting of 15-wt% PTFE micropowder (= 8.1 vol%) has only a small volume content but the AFM picture shows nearly 50% of the area of low adhesion. This means a surface modification takes place during tribological application. PTFE particles are degraded, removed and distributed on the surface by wear and tear and fixated on PA... 

SEM examination shows continuous britfle cracks on the surface of iPP irradiated to 1000 kGy these cracks are attributable to chain scission and oxidative degradation of the iPP (see Section 11.3.2). In comparison, the surface morphology of the irradiated blend (1000 kGy) containing 50% iPP is quite different it shows mainly holes and cavities associated with the detachment of the dispersed mbber particles from the continuous iPP matrix, along with minute discontinuous cracks. The irradiated surface of EVAc (1000 kGy) shows brittle cracks, which are more intense and wider than those in iPP. The tensile failure surface of non-irradiated and irradiated iPP exhibits... 

Bonartsev, A. R et al. Hydrolytic degradation of poly(3-hydroxybutyrate),polylactide and their derivatives kinetics, crystallinity, and surface morphology. Mole. Cryst. Liquid Cryst 2012, 556(1), 288-300. 

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