Immersion process

Platinum Platinum-coated titanium is the most important anode material for impressed-current cathodic protection in seawater. In electrolysis cells, platinum is attacked if the current waveform varies, if oxygen and chlorine are evolved simultaneously, or if some organic substances are present Nevertheless, platinised titanium is employed in tinplate production in Japan s. Although ruthenium dioxide is the most usual coating for dimensionally stable anodes, platinum/iridium, also deposited by thermal decomposition of a metallo-organic paint, is used in sodium chlorate manufacture. Platinum/ruthenium, applied by an immersion process, is recommended for the cathodes of membrane electrolysis cells. ... 

Ultrafiltration (UF) is an important component in wastewater treatment and in food industry [109,110]. With increasing concerns and regulations in environment as well as in food safety, the process of ultrafiltration has become more critical, whereby new technology development to provide faster and more efficient water treatment is not only necessary but also urgent. Currently, conventional polymeric UF membranes are prepared mainly by the phase immersion process, typically generating an asymmetric porous structure with two major limitations (1) relatively low porosity and (2) fairly broad pore-size distribution [111,112],... 

Silica particles surface-imprinted with a TSA of a-chymotrypsin were applied for the enantio-selective hydrolyzation of amides. Surprisingly, the particles showed reverse enantio-selectivity, i. e., the sol-gel imprinted with the L-isomer of the enzyme s TSA showed a higher selectivity for the D-isomer of the substrate [125]. Also Ti02 gels have been imprinted, e.g., with 4-(4-propyloxypheny-lazo)benzoic acid. QCM coated with ultrathin films of this gel were prepared by an immersion process and showed selective binding of the template [ 126]. These examples demonstrate once more the broad applicability of the concept of molecular imprinting. 

Adsorption and immersion processes can also be related through the heat effects. The integral heat of adsorption of Na moles of adsorbate in the vapor state at equilibrium pressure p and temperature T is... 

Heat evolution during immersion processes involving surface rehydration has been found to occur over a 20- to 40-minute interval, so that high precision methods are required if immersion heats include a contribution due to rehydration. The immersion heat determinations were carried out in a microcalorimeter having a temperature sensitivity of 5 X 10 6° C., rapid thermal response, and carefully determined heat transfer characteristics. The calorimetric system has a demonstrated capability of handling heat input rates as low as 0.005 joule per second (15). Samples for immersion were contained in very thin-walled bulbs holding... 

It has long been realized that the heat of adsorption can be calculated more accurately from determinations of heats of immersion than from equilibrium vapor pressures of adsorbates. Harkins and Boyd (8) and Jura and Harkins (10) have discussed the emersion process and have developed an expression for the enthalpy of desorption that is the negative of the one above. That the immersion process is equivalent to the process we are discussing can readily be shown with the aid of the following two-step process ... 

Figure 2.10 Illustrates schematically the Immersion process. Before immersion the enthalpy of the system is...

The change from a closed circle on the dotted line to corresponding open square or closed triangle represents the recovery on drying. The extent of recovery from a water-immersed sample is dependent on how the sample was treated. The heat treatment at higher temperature caused the greater extent of the recovery. The extent of recovery is inversely proportional to the crystallinity in both heat treatments, confirming the trend found on the immersion process. 

The arrows in figs. 5.8b and c Indicate the adhesion and immersion process, respectively. The corresponding work w of adhesion is the isothermal reversible work needed to create one unit area of SG interface, plus one unit area of LG interface under the simultaneous annihilation of 1 unit are of SL interface. 

H-chemical shift NMR imaging patterns of a poly(methacrylic acid) gel containing water with paramagnetic praseodymium ions (Pr " ) were successfully observed, in order to elucidate spatial distribution of Pr " ions in the gel. The chemical shift of water associated with Pr ions in the gel moves largely downfield. By analysing these experimental results, the immersion process of Pr + ions into the network of the polymer gel was spatially clarified. 

The subscript number indicates the sequence of process, while the time (in bracket) shows the immersion/process period. All the components added were... 

Where the corrosion resistance of a coating depends upon its passivity, it is common to follow plating with a conversion coating process to strengthen the passive film. Zinc, cadmium and tin in particular are treated with chromate solutions which thicken their protective oxides and also incorporate in it complex chromates (see Section 1S.3). There are many proprietary processes, especially for zinc and cadmium. Simple immersion processes are used for all three coatings, while electrolytic passivation is us on tinplate lines. Chromate immersion processes are known to benefit copper, brass and silver electrodeposits, and electrolytic chromate treatments improve the performance of nickel and chromium coatings, but they are not used to the extent common for the three first named. 

Kondo et al. reported a novel fabrication method of polymer nanotubes by combination of an alternate layer-by-layer (LbL) assembly of PLLA and PDLA and the siliea template method. Silica nanoparticles with a diameter of 300 nm were alternately immersed in aeetonitrile solutions of PLLA and PDLA at 50 °C. The immersion process was performed for 10 cycles to deposit 10 double layers of PLLA and PDLA. The resulting partieles were then treated with 2.3% aqueous hydrofluoric acid to remove the siliea core. The hollow eapsules have a spherical shape with a diameter of 320 nm and a shell thiekness of approximately 60 nm. Tubular assemblies with an average diameter of 300 nm and lengths of 2-5 pm are obtained by evaporating water at ambient temperature from a water dispersion of the hollow eapsules on a polyethylene terephthalate (PET) substrate. 

The immersion process starts at time t = 0. At all times i > 0, solvent will diffuse out of the film and nonsolvent will diffuse in. If there is a net volume outflow (solvent flux larger than nonsoivent flux) then the film/bath interface is shifted from z = 0, i.e. the actual thickness is reduced. This process will continue until equilibrium is reached (at time t = t) and the membrane has been formed. In order to describe diffusion processes involving a moving boundary adequately, a position coordinate m must be introduced (eq. HI - 44)... 

In this study we present the generation and characterization of PLL-g-PEG gradients prepared by means of an immersion process originally developed for alkanethiols [Fig. 1(b)]. Two different types of PLL-g-PEG gradients with either nonfunctionalized [Fig. 1(c)] or biotinylated PEG chains [Fig. 1(d)] were prepared on titanium and niobium oxide surfaces, respectively, and characterized by means of variable angle spectroscopic eUipsometry (VASE) and x-ray photoelectron spectroscopy (XPS). 

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