Coalescence mobile surface

In the case of the particles accommodating amine ligands, a new phenomenon has been evidenced, namely, a dynamic exchange at the NMR timescale between free and coordinated amines. It has been correlated to the TEM and HREM results, which show that, at the early stage of the reaction, the particles display a spherical aspect and a small size (ca. 2-3 nm), and that after a few hours, the particles coalesce into elongated wormlike particles, still constituted of pure, unoxidized hep ruthenium. This NMR observation is particularly interesting since it evidences for these particles a fluxionality similar to that of molecular clusters, which is well documented. The ruthenium nanoparticles contain coordinated mobile surface hydrides, as recently demonstrated by a combination of NMR techniques in solution, gas phase, and in the solid state. ... 

Coalescence of Drops with a Mobile Surface in a Turbulent Flow of the Emulsion... 

The assumptions made allow us to consider the coalescence of drops with a mobile surface in the same manner as that of drops with a fully retarded surface. The main difference from the case considered in Section 13.6 is in the form of the hydrodynamic resistance factor. If the drops are placed far apart, the factor of hydrodynamic resistance for the relative motion of drops is determined by the formula (11.71), where each of the factors hi and hi is determined according to Hadamar-Rubczynskis formula... 

Curves relating the corrected retention volume to the concentration of moderator (methanol) in the mobile phase [3] are shown in Figure 4. In pure water, the hydrocarbon chains of the brush phase interact with each other and collapse onto the surface in much the same way as drops of an hydrocarbon will coalesce on the... 

In a collision, droplets are flattened a condition for the occurrence of coalescence is, that, within the time scale of passing each other, the layer of liquid polymer between the droplet can be squeezed out until a critical distance of approach has been reached. The rate of approach of the flattened surfaces strongly depends on the nature of the interface this can be rigid or mobile ... 

On a heated substrate the deposited material forms islands as the increased surface mobility and surface tension cause the deposit to coalesce on the surface. With increased deposition the islands grow laterally until the islands become interconnected to form a continuous layer. For FePt the substrate temperature also transforms the sample into the FCT. The island sizes vary with the nominal thicknesses of the deposited layer. Figure 20 is a plot of the coercivity vs. layer thickness for FePt deposited on MgO (001) single crystal substrates at the two temperatures listed on the plot. The coercivity follows a functional form very similar to that predicted for particles in Fig. 2. 

In the Au/Al203/NiAl(100) system, hemispherical particles occur even at low coverage,7 unlike the situation with titania size distribution was narrow, and particles were stable to 600 K, implying low mobility of adsorbed atoms. Paradoxically, on alumina large particles migrate and coalesce faster than small ones, presumably because the metal-support interaction is weaker but with Au/FeO the diffusivity of atoms is higher due to a lower concentration of surface defects. 

Figure 11. Schematic representation of the electrophoretic mobility (A) measurement showing the major components. In an applied electric field, emulsion droplets move according to their surface charge. These charges can electrostatically stabilize an emulsion system by preventing the droplets from coming into contact and coalescing. The motion of the droplets is visually observed, and the electrophoretic mobilities of a number of particles are measured to determine zeta potential. The sedimentation potential (B) is also illustrated.

Figure 13. Electrophoretic mobility (Fen Kem 3000) of the emulsion from Figure 12 after cationic polymer addition (A). The cationic polymer has neutralized the oil droplet surface charge and electrostatically destabilized the emulsion. The photomicrograph (B) shows this destabilized emulsion that has begun to flocculate or a lomerate but that is not coalescing. This electrostatic destabilization is not the only factor affecting emulsion stability. Factors such as interfacial tension and film strength can prevent coalescence of the emulsion droplets, even though they can now closely approach each other and ag omer-...

---