Dip-coating techniques

Dip and Spin Coating. The dip coating technique described for webs can also be used to coat discrete surfaces such as toys and automotive parts. The surface to be coated is suspended on a conveyor and the part dipped into the coating solution. The surface is then removed, the coating drains, then levels to give the desired coverage. The object is then dried or cured in an oven. 

The use of the dip-coating technique allows to obtain different overlay thicknesses by acting on the solution viscosity and extraction speed as stated by the Landau-Levich equation (see (3.14)). In particular, thicker overlays can be obtained by increasing the extraction speed and/or by increasing the solution viscosity. 

According to results obtained with different dsDNA concentrations, 16 ig/mL was chosen as the optimum concentration for full coverage surface of PGE by dip-coating technique, due to its having better reproducibility and sensitivity. 

For instance, a dip-coating technique can be used to prepare GaN films from either [Ga(N3)3]o= or the base-stabilized species . A unique azide that contains no carbon or hydrogen is [Cl2GaN3]3. It can be used to form GaN under ultra high vacuum CVD conditions . A related derivative, monomeric Cl2GaN3-NMe3, has a higher vapor pressure and can be used to form pure GaN (1-2 atom % carbon and chlorine) more effectively ... 

The precipitate was separated from the excess liquid by centrifugation and washed once with acetone. The precipitate was dried at 120 °C for 10 h. The dried powder was consecutively calcined at 1000 °C and then at 1200 °C for 4 h each. Samples were taken out after each calcination. Finally a small fraction of the powder was aged at 1400 °C in 15% steam for 10 h. The main fraction of the powder was ball-milled and washcoated onto cordierite monoliths (Coming 400 cpsi) by dip-coating technique. The washcoated catalysts were then calcined at 1000 °C for 4 h. 

Sanchez, M. and Rincon, M. E. (2009) Sensor response of sol-gel multiwalled carbon nanotubes-Ti02 composites deposited by screen-printing and dip-coating techniques . Sens. Actuat. B, 140,17-23. 

Patil et al. synthesized PPy/polyacrylic acid (PAA)Zsilver (Ag) composite electrodes by chemical polymerization via a simple and cost-effective dip-coating technique for supercapacitor application [75]. The higher SC and specific energy of the PPY/PAA/Ag composite of 226 F/g and 17.45... 

Pd [22], Si02 [45], and Ti02 [85] films deposited on the surface of Nafion membranes by sputtering, plasma vapour deposition, and dip-coating, respectively, does not show relevant characteristics for DMFC. However, Si02 layers deposited on both surface of Nafion 117 membranes by a simple dip-coating technique [38] leads to the highest reported values of relative selectivity (P =650 at 25 °C, and Pi = 220 at 80 °C), not shown in Fig. 6.22. These membranes show an unexpected... 

PV is a promising option to enhance the conversion of reversible condensation reactions in which water is formed as a by-product. Peters et al. (2005) prepared composite catalytic membranes by a dip-coating technique. Composite catalytic membranes have been prepared by applying a zeolite coating on top of ceramic hf silica membranes. In the PV-assisted esterification reaction, the catalytic manbrane was able to couple catalytic activity and water removal. A reactor evaluation proved that the outlet conversion of the catalytic PV-assisted esterification reaction exceeded the conversion of a conventional inert PV membrane reactor, with the same loading of catalyst dispersed in the bulk liquid. Further, the performance of the zeolite-coated PV membranes can be increased by optimization of the catalytic layer thickness or by an increase in catalytic activity. 

Non-destructive surface-functionalization of carbon nanofibers can be achieved by using poly(3,4-ethylenedioxythiophene) (PEDOT) since PEDOT is an electron donor and carbon nanofiber is an electron acceptor [40]. PEDOT/carbon nanofiber nanocomposites can be prepared by chemical polymerization process. This includes an initial adsorption of EDOT monomers on the carbon nanofibers, which is followed by the polymerization process. The adsorption of monomers on the fiber surface occurs due to the electrostatic n-n interaction. PEDOT poly(styrenesulfonate) (PEDOT PSS)/carbon nanofiber bilayer system is used particularly for electrode applications [41]. Such bilayer systems can be easily prepared with dip-coating technique.The advantage of dip-coating is that only a small amount of polymer will be adsorbed on the carbon nanofiber surface and hence nanometer thick coating is achievable. The surface area of electroactive materials can be enhanced in such bilayer systems prepared with carbon nanofibers. 

The influence ofTiOj morphology on permeate flux through a photocatalytic polymer membrane prepared by the dip coating technique. (Adapted from Bai eta ., 2010.)... 

The dip coating technique has been shown to yield uniaxially planar aligned eolum-nar fibers onto substrate surfaces. Dovetailed HBC 52 (Scheme 3.17) revealed... 

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