Microtopographical surfaces

Interfacial behavior of different silicones was extensively studied, as indicated in Section 3.12.4.6. To add a few more examples, solution behavior of water-soluble polysiloxanes carrying different pendant hydrophilic groups, thus differing in hydrophobicity, was reported.584 A study of the aggregation phenomena of POSS in the presence of amphiphilic PDMS at the air/water interface was conducted in an attempt to elucidate nanofiller-aggregation mechanisms.585 An interesting phenomenon of the spontaneous formation of stable microtopographical surface domains, composed primarily of PDMS surrounded by polyurethane matrix, was observed in the synthesis of a cross-linked PDMS-polyurethane films.586... 

Majumdar, P., Stafslien, S., Daniels, J., and Webster, D.C. (2007) High throughput combinatorial characterization of thermosetting siloxane-urethane coatings having spontaneously formed microtopographical surfaces. J. Coat. Technol. Res., 4, 131-138. 

K. Onuma, K. Tsukamoto, and I. Sunagawa, Effect of buoyancy driven convection upon the surface microtopographs of BalNOjjj and Cdl crystalsJ. Crystal Growth, 98,1989, 384-90... 

Figure 4.14. Changes observed on Tracht and surface microtopographs of 100 and 210) faces of pyrite crystals as growth proceeds (see ref. [1], Chapter 2).

Figure 5.1. Surface microtopographs seen on three types of crystal faces (Kossel crystal), (a) F face (b) S face (c) K face.

The earliest interest in surface microtopographs observable on crystal faces developed in the 1920s these observations were made using reflection-type microscopes on etch figures seen in natural mineral crystals [1], [2]. At that time. 

An example is shown in Fig. 5.10(b). However, step patterns observed on the same crystal face of the same crystal species collected from different locations usually exhibit characteristic patterns that are recognizable enough to indicate the locality of origin. This is because surface microtopographs reflect very sensitively the difference in growth conditions at respective sites. 

We may assume that the surface microtopographs that appear due to growth are symmetrical to those that appear by dissolution, since the processes of... 

Figure 9.11. (a) Surface microtopograph (phase contrast photograph taken by K. Tsukamoto) and (b) X-ray topograph (taken by T. Yasuda [12]) of a (111) face. Steps with height of less than 0.5 nm spread from the outcrops of dislocations HI and H2. 

Sunagawa, K. Tsukamoto, and T. Yasuda, Surface microtopographic and X-ray topographic study of octahedral crystals of natural diamond from Siberia, InMoterioIs Science of the Earth s Interior, ed. I. Sunagawa, Dordrecht, D. Reidel, 1984... 

Figure 10.12. Change in form and surface microtopographs observed in regrowth experiments on ajapanese twinned sample used as a seed [15]. When thejapanese twin grows freely, the form changes from a V-shape to a Y-shape.

From the surface microtopographic characteristics summarized above, it is concluded that the order of morphological importance of p5U ite is 100 > 111 > 210. This order is in agreement with the results of PBC analysis. 

The morphology of single crystals, the surface microtopographs of crystal... 

In volcanic rocks formed by the solidification of magma near the Earth s surface, small cavities of millimeter to centimeter order are often present, in which idiomorphic crystals of phlogopite and hematite occur. All these crystals grown from the vapor phase show typical spiral patterns. However, they grow in a much-reduced free space as compared to the case of pegmatite, and this characteristic is well represented on their surface microtopographs. 

Figure 12.13. Surface microtopograph of hematite from a druse of ryoUte. A large number of minute hematite crystals adhere and affect the advancement of the spiral growth layers on the host crystal.

Figure 13.1. Two examples of surface microtopographs of kaolinite using the decoration method [1].

Biologically active molecules are sometimes trapped in PDMS when end-functionalized PDMS chains are linked into a network structure. This method has been done, for example, with a lipase enzyme. The PDMS plays a beneficial role as an activator or protective agent. Similar results were found for the enzyme a-chymotripsin, with some short-chain poly(ethylene oxide) used to enhance enzymatic activity. It is also possible to generate microtopographic patterns that affect Escherichia coU biofilm formation on PDMS surfaces. 

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