Ultrasonic deposition

Shiffelt M.B. and Foley H.C. (1999) Ultrasonic deposition of high-selectivity nanoporous carbon membranes. Science 5435, 1902-1905. 

PFA was rrsed exterrsively as a precnrsor dnring the preparation of nanoporons carbon (NPC) merrtbrane for gas separation by Foley and co-workers [52-58]. An early work had rmcovered the rrse of a spray-coating techniqne in order to prodnce a thinlayer of NPC inthe pororrs snrface of a stainless steel disk snpport [51,54]. Selectivity for O2/N2 separation of np to 4 was achieved for the snpported membrane carborrized at 600°C in flowing helitrm [54]. Later Foley arrd co-workers improved their preparation techrrique by using an ultrasonic deposition system which conld rrrriformly distribute the polymeric solution on to the support [52, 53, 57], They have fabricated a number of thin film supported nonporous carbon membranes... 

For making the supported carbon membranes, various options are available for coating the supports with thin polymeric films, such as ultrasonic deposition [52, 53], dip coating [68], vapour deposition [60], spin coating [43], and spray coating [54], Ultrasonic deposition (UD) provides nearly zero spray velocity, droplet sizes that are often narrowly distributed in sizes from 10 to 10 pm, accurate compared to spray and misting [52]. 

Shiflett and co-workers coated thin uniform layers of PFA (Dija laboratories) to porous stainless steel tubes by ultrasonic deposition and carbonized at 723 K to form crack-free supported nonporous carbon (NPC) membranes [10]. Methyl chloride porometry was performed with variation in both pressure and temperatwe. Figure 6.27 shows the results of the measurement and calculation. Applying Hor-... 

The PFA membranes presented here were presented by Shiflett and Foley (1999, 2000, 2001). These membranes were synthesized by ultrasonically depositing a layer of PFA on a stainless steel support followed by drying and subsequent pyrolysis. This process was then repeated several times to form the resulting supported membranes. This process may result in an asymmetric membrane, and authors have also shown that producing reproducible properties for this type of membrane is difficult (Shiflett and Foley, 2001). The... 

As the vast majority of LC separations are carried out by means of gradient-elution RPLC, solvent-elimination RPLC-FUR interfaces suitable for the elimination of aqueous eluent contents are of considerable use. RPLC-FTTR systems based on TSP, PB and ultrasonic nebulisa-tion can handle relatively high flows of aqueous eluents (0.3-1 ml.min 1) and allow the use of conventional-size LC. However, due to diffuse spray characteristics and poor efficiency of analyte transfer to the substrate, their applicability is limited, with moderate (100 ng) to unfavourable (l-10pg) identification limits (mass injected). Better results (0.5-5 ng injected) are obtained with pneumatic and electrospray nebulisers, especially in combination with ZnSe substrates. Pneumatic LC-FI1R interfaces combine rapid solvent elimination with a relatively narrow spray. This allows deposition of analytes in narrow spots, so that FUR transmission microscopy achieves mass sensitivities in the low- or even sub-ng range. The flow-rates that can be handled directly by these systems are 2-50 pLmin-1, which means that micro- or narrow-bore LC (i.d. 0.2-1 mm) has to be applied. 

Flower shaped crystalline deposit on the surface of the solid non-crystalline mass of platinum sulphide was probably due to the precipitation of elemental sulphur, which deposited as a floral growth on the non-crystalline platinum sulphide precipitate. Ultrasonic irradiation seemed to have broken tender sulphur flakes and cleaned the surface. The free sulphur, however, did not deposit further. This was probably due to the formation of other compounds of sulphur such as H2S, S02, etc. which could have been removed from the solution due to the phenomenon of degassing. 

Nina P, Galina A, Claudio R, de la Fernando Vega, Aharon Gedanken (2009) Sonochemical deposition of magnetite on silver nanocrystals. Ultrason Sonochem 16(1) 132—135... 

Three different reactors were used to deposit CuInS2 films via AACVD. Reactor A, shown schematically in Fig. 6.11a, was primarily used in the parametric studies described below. This is a horizontal, atmospheric pressure, hot-wall reactor with a plate-type 2.5-MHz ultrasonic nebulizer from Sonaer Ultrasonics. The precursor (1.5-3.5g) was dissolved into distilled toluene (50-400 ml) and fed into the nebulizer using a syringe pump. The nebulizer... 

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