Interfacial polymerization method

Interfdci l Composite Membra.nes, A method of making asymmetric membranes involving interfacial polymerization was developed in the 1960s. This technique was used to produce reverse osmosis membranes with dramatically improved salt rejections and water fluxes compared to those prepared by the Loeb-Sourirajan process (28). In the interfacial polymerization method, an aqueous solution of a reactive prepolymer, such as polyamine, is first deposited in the pores of a microporous support membrane, typically a polysulfone ultrafUtration membrane. The amine-loaded support is then immersed in a water-immiscible solvent solution containing a reactant, for example, a diacid chloride in hexane. The amine and acid chloride then react at the interface of the two solutions to form a densely cross-linked, extremely thin membrane layer. This preparation method is shown schematically in Figure 15. The first membrane made was based on polyethylenimine cross-linked with toluene-2,4-diisocyanate (28). The process was later refined at FilmTec Corporation (29,30) and at UOP (31) in the United States, and at Nitto (32) in Japan. 

Because almost any diacid can be leaddy converted to the acid chloride, this reaction is quite versatile and several variations have been developed. In the interfacial polymerization method the reaction occurs at the boundary of two phases one contains a solution of the acid chloride in a water-immiscible solvent and the other is a solution of the diamine in water with an inorganic base and a surfactant (48). In the solution method, only one phase is present, which contains a solution of the diamine and diacid chloride. An organic base is added as an acceptor for the hydrogen chloride produced in the reaction (49). Following any of these methods of preparation, the polymer is exposed to water and the acid chloride end is converted to a carboxyhc acid end. However, it is very difficult to remove all traces of chloride from the polymer, even with repeated washings with a strong base. 

When the reactants involved in a step growth polymerization process are mutually immiscible, we can employ an interfacial polymerization method. Two solutions, each containing one of the monomers, are layered one on top of the other. This creates a phase boundary that forms wth the least dense liquid on top. The different monomers can then meet and polymerize at the interface. A commonly demonstrated example of this is the manufacture of nylon 610 by the interfacial reaction between an aqueous solution of hexamethylenediamine with sebacoyl chloride dissolved in carbon tetrachloride. Because the reaction only occurs at the interface, it is possible to pull the products from this interface to isolate the final product. 

Details of this experiment may be found in Ref. 1. The interfacial polymerization method to prepare polyamides involves the reaction of a diacid dichloride with a diamine between two immiscible liquids as the reaction zone (with or without stirring). The method is useful where the reactants are sensitive to high temperature and where the polymer degrades before the melt point is reached (as in melt polymerization techniques). 

Makino et al. [63] measured the electrophoretic mobility of four types M1-M4 of hydrophilic gel microcapsules containing water prepared by an interfacial polymerization method. Each type of microcapsules has membranes of different compositions. The results of the analysis of the measured mobilitiy values on the basis of Eqs. (21.128) are given in Figs 21.10 and 21.11. 

Alilla A and Kas HS. Microencapsulation technology Interfacial polymerization method. In Wise DL, ed. Handbook of Pharmaceutical Controlled Release Technology. New York, Basel Marcel Dekker, 2000, pp. 271-285. 

Solid-State Mechanochemical Synthesis Facile template-free solid-state mechano-chemical synthesis of highly branched PANI-NFs with coralloid tree-like superstrueture, via the oxidative polymerization of aniline hydrochloride with FeCl3 6H2O, has been demonstrated [194]. The synthetic yield ( 8%) was comparable to that of the solution interfacial polymerization method. Solid-phase mechanochemical synthesis of branched PANI-NFs was also achieved by using anhydrous FeCl3 as the oxidant [195]. 

PANI-CS A nanofibers, synthesized by an interfacial polymerization method, are readily dispersed in water, which could facilitate environmentally friendly processing and biological applications [133]. The nanofibers are stable in water, in contrast to conventional PANI/CSA thin films, which can be dedoped by water. PANI-NFs synthesized by dilute polymerization were also easily dispersed in various solvents, polar as well as nonpolar, and the resulting suspensions were stable for several minutes [171]. 

S. Xing, H. Zheng, and G. Zhao, Preparation of polyaniline nanofibers via a novel interfacial polymerization method, Synth. Met., 158, 59-63 (2008). 

The low temperature precipitating polymerization method comprises the polymerization reaction in an organic solvent which is sparingly soluble in water, such as methyl ethyl ketone, and in an aqueous solvent by using triethylamine as an acid acceptor. This reaction is a kind of interfacial polymerization method. ... 

Cai et at developed PEDOT/PbTe composite by adding PbTe nanoparticles into a polymerization media [20]. The PEDOT nanotubes were in-situ fabricated by an interfacial polymerization method. The PbTe nanoparticles (-20-50 nm) acted as solid stabilizer and were adsorbed on the surface of the PEDOT nanotubes at the acetonitrile/n-hexane interface (Figure 6.10). The materials exhibit extremely large Seebeck coefficient values, which is promising for TE applications. 

Y. Wang et al. fabricated PANI/PbTe composite nanopowders via an interfacial polymerization method at room temperature [22]. The... 

Till date, liquid-crystalline phases [51], colloidal particles [52], and structure-directing molecules [53[ as the soft-template have been employed to synthesize PANI nanostructures. Based on the traditional synthesis method of PANI, in particular, some simple approaches such as interfacial polymerization [54], mixed reactions [55], dilute polymerization [56] and ultrasonic irradiation [57] have also been employed to synthesize PANI. The interfacial polymerization method only allows the oxidative polymerization of aniline to take place at the interface of the organic/water phases and the product directly enters into the water phase, which could facilitate environmentally friendly processing. 

Another route for the preparation of the polyamides is the interfacial polymerization method. In this method the diamine is dissolved in water (which usually also contains a base such as potassium hydroxide for scavenging the HCl formed in the reaction). The diacid chloride is dissolved in an organic solvent such as dichloromethane or tetrachloroethylene. These two solutions are brought in contact with each other. The polymer is formed at the interface of the two immiscible solvent systems. An example of this polymerization is shown in Eq. 2.62. 

Chu et al. [70] demonstrated a simple and effective route for the hydrophilic surface modification of ceramic-supported PES membranes by synthesizing a polyfvinyl alcohol) (PVA)/polyamide (PA) composite thin sinface layer with an interfacial polymerization method (IP) method. The reaction of the interfadal polymerization is schematically shown in Figure 2.7. A prepared tubular ceramic-supported PES membrane (both ends sealed) was immersed in a terephthaloyl chloride solution in benzene and... 

The surface of the membrane opposite to the Au film was then coated with an ultrathin (ca. 50 nm) skin of a pol dimethylsiloxane) this was accomplished by using a novel interfacial polymerization method developed in these laboratories (22). Briefly, the alumina support membrane is placed on a wet filter paper, which acts as a source of water vapor. The upper face of the membrane is then exposed to dimethlydichlorosilane vapor. T causes a thin skin of poly(dimethylsiloxane) to form across the upper surface of the membrane. The films used in the sensors described here were on the order of 50 nm in thickness. 

Figure 16-1, Schematic illustration of gel film formation process hy an interfacial polymerization method.

Tsurumi T., Ozawa S., Wada S. Preparation of PZT thick films by an interfacial polymerization method. J. Sol-Gel Sci. Technol. 2003 26 1037-1040 Yamane M. Thick silicate film by an interfacial polymerization. J. Sol-Gel Sci. Technol. 1997 8 483 87... 

Interfacial polymerization techniques can be used to prepare robust microcapsules (about 4 pm) that have selectively incorporated functionality such as catalytic groups in their liquid-core domains. The synthesis of these particles is achieved via an oil-in-oil emulsion in combination with interfacial polymerization methods and allows for the encapsulation of substrates not compatible with water-in-oil or oil-in-water emulsion systems (Kobalija and McQuade, 2006). Often these capsules have polyurea shells that can be formed from w/o emulsions containing reactive polyols and isocyanates. This has been very elegantly demonstrated by McQuade and coworkers for the DMAP-catalyzed acylation transformation of an alcohol within the protected environment of polyurea microcapsules formed from reaction of a polyisocyanate and a poly(vinyl alcohol) in the presence of an amine catalyst (Price et ah, 2006 Poe et al, 2007). 

Interfacial polymerization method with embedded proteoliposomes 4 0.4 96.3 1.2 14... 

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