Homogeneous coating

Whatever application method is used, there is always a heating step. When p.v.c. plastisol is heated to over 100°C the p.v.c. resin which is suspended in plasticiser stabiliser etc. starts to dissolve in the plasticisers. When solution is complete the system is cooled to room temperature and a solid homogeneous coating results. 

TEM micrographs of a neat PS particle (a) and those coated with one to five Si02/PDAD-MAC multilayers (b-f). The nncoated PS latices are spherical and feature a smooth surface (a). The presence of SiOi/PDADMAC mnltilayers on the PS latices result in both an increase in surface roughness (dne to SiOi) and a systematic increase in the diameter of the PS latices (b-f). Consistent with the SPLS and SEM measnrements, the PS particles are homogeneously coated with nanoparticles. The TEM data (Fig. 6) yield an average diame-... 

Du, N., et al., Homogeneous coating ofAu andSn02 nanocrystals on carbon nanotubes via layer-by-layer assembly a new ternary hybrid for a room-temperature CO gas sensor. Chemical Communications, 2008(46) p. 6182-6184. 

In the development of the aforementioned time-dependent systems, care has to be taken to ensure a homogeneous coating. If the coat is not homogenous, its rigidity will be affected, possibly leading to undesirable infiltration of the aqueous medium and, in turn, imdesired alteration of the lag time before which the drug is supposed to be released. 

Fig. 35 Crystallization of non-spherical particles homogeneously coated with DNA. (a, b) Schematic of a hexagonal close-packed 2D layer in assemblies of gold nanorods and corresponding structure factor S(q) obtained from SAXS measurements (blue line) and simulations (red line), (c, d) Schematic of ID columnar assembly of gold triangular nanoprisms and corresponding SAXS patterns, (e, f) Schematic of the 3D fee assembly of gold rhombic dodecahedra (the lines indicate the fee unit cell) and corresponding SAXS patterns. Adapted with permission from [152]...

Care had to be taken in the preparation of suitable homogeneous coated tubular bromide-selective electrodes from silver bromide. Maximum contact area is obtained by using a tubular electrode that is well-coated. The maximum sensitivity was obtained when the electrode was coated, tested, left in ca. 500 mg/dm3 bromide solution, recoated, etc., until maximum response was obtained, and then conditioned overnight in 20 mg/dm3 bromide solution. It was also necessary to carry out an actual test run of about ten minutes. 

In a first experiment with fibroblasts in culture, an extended 73-nm-spaced pattern was compared with a 2-pm-patterned 58-nm array. Although the total nanoparticle density of the micropatterned surface was considerably lower than that of the homogeneously coated one, the cells could only form FAs on 58-nm-spaced RGD motives. It is thus obvious that integrin function critically depends on the spatial confinement of integrins to favour clustering but not on the total number of bound integrins [82],... 

Homogeneous coatings were obtained by driving a constant current density of 5 mAcm 2 at 50 °C, without stirring for 60 min. 

The impact of symmetry control on the homogeneity of film properties for large-area ZnO Al coating is shown in Fig. 5.30. Homogeneous coatings with acceptable variation of transmittance and sheet resistance have been achieved. The concept of symmetry control described here is well known in the glass industry. Other implementations have been realized using multiple PEM sensors [43],... 

A homogeneously coated 6.6 nm layer was used and part of the layer was removed by increasing etching times. Two (major) effects have been noted ... 

Carbon coating can be achieved using pyrolysis of hydrocarbons at elevated temperatures [69]. Figure 2 shows a device used for carbon coating via hydrocarbon pyrolysis. In the example described here, an alumina-washcoated monolith is covered with carbon by pyrolysis of cyclohexene. A gas mixture of cyclohexene in nitrogen is passing the reactor at a certain flow rate. The monolith block to be coated is placed in the middle of the heated tubular reactor. The reaction takes place at 873-973 K, and the amount of carbon deposited can be controlled by the temperature and the time on stream. Up to 3-10 wt% carbon can be homogeneously coated onto the monolith in this way. It appears that the surface area of the carbon-coated alumina-washcoated cordierite monolith is of... 

It is well known that experimental CVs for species in solution phase frequently diverge from theoretical ones for -electron reversible couples. The divergence can be caused by a variety of factors deviations from reversibility, occurrence of coupled chemical reactions and/or surface effects, and resistive and capacitive effects (Nicholson and Shain, 1964 Nicholson, 1965a). These last effects will be briefly treated here because of their potential significance when microheterogenous deposits or more or less homogeneous coatings of microporous materials cover the electrode surface. 

Late in the 1960s, it became apparent that catalyzed lacquers, the hardest, most durable nitrocellulose lacquers commercially available for coating wood, had less resistance to alcohol, cosmetics, and chemicals than did the best quality alkyd-amine compositions or high-pressure melamine overlays. This situation was soon remedied by the development of nitrocellulose-urethane "super lacquers" based on nitrocellulose-isocyanate prepolymers (16). Nitrocellulose as manufactured contains free hydroxyl groups that can provide sites for true cross-linking with an isocyanate-bonded homogeneous coating. Laboratory studies confirmed the theoretical reaction ... 

---