Film-forming apparatus

In the ink-jet method, since the material is jetted and is scattered, if a distance between a coated surface and a nozzle of a head for ink-jet is not made suitably, there can occur the problem of a so-called flying curve in which a droplet falls to a position other than intended. To overcome this undesired behavior, an improved thin film-forming apparatus has been constructed. ... 

The apparatus used to make small sections of water-cast composite membranes is shown in Figure 3.23. The dilute polymer solution is cast on the surface between two Teflon rods. The rods are then moved apart to spread the film. The thin polymer film formed on the water surface is picked up on a microporous support. The main problem with this method is the transfer of the fragile, ultrathin film onto the microporous support. This is usually done by sliding the support... 

Characterization of the bearing surface film, and film formed in a lubricated cam/tappet friction apparatus have been analyzed by reflectance-absorption infrared, X-ray photoelectron (XPS) and Auger electron (AES) spectroscopies (Lindsay et al., 1993). The two lubricants used were similar to fully formulated engine oils. 

The blue film, formed by distillation of l-alkyl-2-carbomethoxypyridinyl radical, 2, onto a 77 K surface, disappears on warming. The thin film spectroscopy apparatus depicted in Fig. 3 allowed a) direct cooling of the condensing surface so that tern-... 

The mutual attraction through the slit gap affects liquid film stability, and at a certain critical vapor pressure (or film thickness) the two films form a liquid bridge (Fig. 1-1 c) followed by a spontaneous filling up of the slit (assuming the film is in contact with the bulk liquid phase). The liquid-vapor interface moves to the plate boundaries. This phase transition from dilute vapor to a dense liquid is known as capillary condensation and was observed experimentally with the surface force apparatus by Christenson (1994) and Curry and Christenson (1996). Extensive theories for this phenomenon and its critical points are provided by Derjaguin and Chu-raev (1976), Evans et al. (1986), Forcada (1993), and Iwamatsu and Horii (1996). In general, slit-shaped pores fill up at a film thickness of about HI3, or when <) l(H,h)/dh = 0, such that... 

Microsublimation is less often complicated by inclusion of involatile impurities in the film formed on sublimation. If formed, this film coats the surface of the solid, thus hindering vaporization of the material in the interior of the crystals thus it is always advisable to add the substance in solution and then to evaporate the solvent slowly, so that the substance forms a thin layer in the lower part of the apparatus. 

For these main forms components were designed which may be assembled to give multistage thin-film distillation apparatus for degassing and distillation at various temperatures. Further development has led to short-path distillation units with internal condensation and rotating wipers, which may also be combined to operate as multistage apparatus (see chap. 5.4.4). 

The apparatus used in our study of thin liquid films is shown diagrammatically in Fig. 1 [16, 17, 85, 86]. There is a hole (0.5 mm in diameter) in the side of the Teflon chamber, which separates two aqueous solutions. The oil phase containing film-forming substances is introduced into the hole with the aid of a small syringe (ATP Inc., MI, USA). The film capacitance (Cm) and resistance were measured by a Multi-Function Analyzer (Sino-Jinke Electronics Co. Ltd, Tianjin, China). The thickness of thin liquid films, according to the parallel-plate formula, is given by... 

FIG. 13 Schematic diagram of the cell for formation of films formed by a frame pulled out of a solution. The sizes of the apparatus are shown in mm. 

The die is a circular apparatus with a slit around the circumference of the die where the molten polyethylene exits the extruder to begin the blown-film-forming step. 

FIGURE 4.82 Effect of spherical hydrophobed silica particles on stability of pseudoemulsion film formed by heptanes in saline aqueous solutions of AOT. (a) Apparatus used. Contact angles were varied by changing AOT concentration, (b) Plot of heptane drop half-life against + Bow (see text). (Aveyard, R., Clint, J.H., JCS Faraday Trans., 91, 2681, 1995. Reproduced by permission of The Royal Society of Chemistry.)... 

Fig. 12. Transfer film formed on abraded steel (AISI 02 tool steel) surface (i a = 0.11 fim) as a result of dry sliding (a) unfilled and (b) filled PEEK after 70,000 cycles of sliding. The filled specimen had 25 vol% of CuS + 10 vol% of PTFE. The unfilled PEEK specimen does not show uniform film formation and, in contrast, the filled specimen forms uniformly covered film on the steel counterface. The tests were conducted on a pin-on-disk apparatus with 63 mm track diameter, sliding velocity 1 m/s and a normal load of 19.6 N (pressure 0.654 MPa). There was about 90% reduction in the wear rate as a result of transfer film formation, while the coefficient of friction for the composite was higher ( 0.43) in comparison to that for the virgin PEEK ( 0.4) (75). It was concluded in this work that first Cu atoms are formed as a result of reduction of CuS during the sliding interaction. Then fluorine atoms in the PTFE molecules react with Fe atoms of the counterface in the presence of Cu and thus forming FeF2. This chemical reaction helped in the formation of strong transfer layer on the counterface which was not possible for the case of PEEK with CuS (40 vol%) alone without the presence of PTFE molecules. Reprinted from Ref. 75, copyright 1995, with kind permission om Elsevier Science.

---