Plasma polymerization membrane

The most extensive studies of plasma-polymerized membranes were performed in the 1970s and early 1980s by Yasuda, who tried to develop high-performance reverse osmosis membranes by depositing plasma films onto microporous poly-sulfone films [60,61]. More recently other workers have studied the gas permeability of plasma-polymerized films. For example, Stancell and Spencer [62] were able to obtain a gas separation plasma membrane with a hydrogen/methane selectivity of almost 300, and Kawakami et al. [63] have reported plasma membranes... 

The process shown in Figure 9.21 was first developed by Separex, using cellulose acetate membranes. The separation factor for methanol from MTBE is high (>1000) because the membrane material, cellulose acetate, is relatively glassy and hydrophilic. Thus, both the mobility selectivity term and the sorption term in Equation (9.5) significantly favor permeation of the smaller molecule, methanol, because methanol is more polar than MTBE or isobutene, the other feed components. These membranes are reported to work well for feed methanol concentrations up to 6%. Above this concentration, the membrane is plasticized, and selectivity is lost. More recently, Sulzer (GFT) has also studied this separation using their plasma-polymerized membrane [56],... 

G. Ellinghorst, H. Steinhauser and A. Hubner, Improvement of Pervaporation Plant by Choice of PVA or Plasma Polymerized Membranes, in Proceedings of Sixth International Conference on Pervaporation Processes in the Chemical Industry, R. Bakish (ed.), Bakish Materials Corp., Englewood, NJ, pp. 484-493 (1992). 

Since dicyclohexyl-18Crown-6 (DC18C6) has the ability to take up ions and to transfer them across a lipophiUc medium, it has widely been used in or nic synthesis, in ion-extraction into nonpolar solvents, as chiral complexing agents, etc. Osada, Shinkai, et al. have found that membranes prepared under proper conditions retain the structure of the original crown compounds sufficiently to recognize metal ions and v,j+/Vl,+ and V,j+/vcs+ (ratios of ion-permeation rates) for plasma-polymerized membranes were 3.7 and 3.4, respectively [75],... 

Yamamoto M, Sakata J, Hirai M. 1984. Plasma polymerized membranes and gas permeabihties. J. Appl. Polym. Sci. 29 2981-2987. 

Matsuyama, H., Hirai, K. and Teramoto, M. 1994. Selective permeation of carbon dioxide through plasma polymerized membrane from diisopropylamine. J Memh a. 3 257-265. 

Kita, H. Sakamoto, T. Tanaka, K. Okamoto, K.-L, Preparation of Plasma-Polymerized Membranes from l-(Trimethylsil)d)-I-Propyne and Gas Permeability Through the Membranes. Polym. Bull. 1988,20, 349-354. 

Roualdes, S., Topala, I., Mahdjoub, H., Rouessac, V., Sistat, P., Durand, J. (2006) SuRonated polystyrene-type plasma-polymerized membranes for miniamre direct methanol fuel cells. Journal of Power Sources, 158, 1270-1281. 

In a previous section, the effect of plasma on PVA surface for pervaporation processes was also mentioned. In fact, plasma treatment is a surface-modification method to control the hydrophilicity-hydrophobicity balance of polymer materials in order to optimize their properties in various domains, such as adhesion, biocompatibility and membrane-separation techniques. Non-porous PVA membranes were prepared by the cast-evaporating method and covered with an allyl alcohol or acrylic acid plasma-polymerized layer the effect of plasma treatment on the increase of PVA membrane surface hydrophobicity was checked [37].The allyl alcohol plasma layer was weakly crosslinked, in contrast to the acrylic acid layer. The best results for the dehydration of ethanol were obtained using allyl alcohol treatment. The selectivity of treated membrane (H20 wt% in the pervaporate in the range 83-92 and a water selectivity, aH2o, of 250 at 25 °C) is higher than that of the non-treated one (aH2o = 19) as well as that of the acrylic acid treated membrane (aH2o = 22). 

Yasuda, H. "Composite Reverse Osmosis Membranes Prepared by Plasma Polymerization," in "Reverse Osmosis and Synthetic Membranes," Sourirajan, S., Ed., National Research Council, Canada, Ottawa, 1977, p.263. 

Plasma polymerization of films was first used to form electrical insulation and protective coatings, but a number of workers have also prepared selective membranes by this method [60-63], A simple plasma polymerization apparatus is... 

H. Yasuda, Plasma Polymerization for Protective Coatings and Composite Membranes, 7. Membr. Sci. 18, 273 (1984). 

Figure 11.1 Model of a composite membrane, bending because of a stress in the thin layer deposited by plasma polymerization onto a flexible polymeric substrate layer and substrate have thickness d and D and Young s module e and E, respectively.

Figure 34.3 Modes of plasma polymerization coating, (a) on nonporous membrane, and (b) on porous membrane.

Figure 34.13 Reverse osmosis characteristics of composite membranes prepared by plasma polymerization of benzene/H20/N2 compared with those from acetylene/H20/ N2 represented by the solid line porous polysulfone film as the substrate, 3.5% NaCl at 1500 psi.

Figure 34.16 Change of salt rejection and water flux with time (1.2% NaCl, 1300 psi) membrane of plasma-polymerized 4-vinylpyridine on Millipore vs filter.

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