Membranes block copolymer

Mass-polymerized PVC also has a skin of compacted PVC primary particles very similar in thickness and appearance to the suspension-polymerized PVC skin, compared in Figure 3. However, mass PVC does not contain the thin-block copolymer membrane (7). 

Rubatat, L., Shi, Z. Q., Diat, O., Holdcroft, S. and Frisken, B. J. 2006. Structural study of proton-conducting fluorous block copolymer membranes. Macromolecules 39 720-730. 

A system with clearly defined disperse (A) and continuous (B) component phases is afforded by copolymers of styrene (A) grafted onto a polydimethyl siloxane matrix (B)101 Lack of appreciable interaction between the components was indicated by gas solubility and Tg measurements. The permeability coefficient of propane and other paraffins over a composition range vA = 0 — 0.55 followed the trend described by Eqs. (30)—(33) (with PA = 0, in view of the fact that the polystyrene phase is practically impermeable). Of particular relevance to the present discussion is the close agreement with the Bruggeman, and definite deviation from the Bottcher, equations at higher vA (cf. Fig. 11). Corresponding block copolymer membranes with vA = 0.34 also fitted into this pattern, except in one case where the structure was found to be lamellar and P was considerably lower. 

Using the block copolymer membranes described above, significant selectivi-ties for electrolytes over non-electrolytes have been observed. Some data reported by Hirahara el al. [17] are shown in Table 13.1. The ionizable electrolytes were 100 times more permeable than non-ionized solutes such as glucose and sucrose, suggesting a number of potential applications in which deionization of mixed solutions is desirable. The permeabilities of salts in these membranes are also... 

Tsujita Y, Yoshimura K, Yoshimizu H, Takizawa A, Kinoshita T, Furukawa M, Yamada Y, Wada K (1993) Structure and gas permeability of siloxane-imide block copolymer membranes 1 effect of siloxane content. Polymer 34(12) 2597... 

Dutta BK and Sikdar SK. Separation of volatile organic compounds from aqueous solutions by pervaporation using S-B-S block copolymer membranes. Env. Sci. Tech. 1999 33(10) 1709-1716. 

Tsubouchi K and Yoshikawa M. Pervaporation separation of benzene/cyclohexane mixtures through polyamide-polyether block copolymer membranes. Membrane (Maku) 1998 23(6) 322-326. 

Keywords Amphiphilic block copolymers, Membranes, Nanoreactors, Polymer-somes, Self-assembly, Stimuli-responsive vesicles... 

General Aspects of Block Copolymer Membrane Formation. 117... 

Pioneering work in the incorporation of functional proteins into polymer bilayers was performed by Meier et al., who integrated membrane proteins into black block copolymer membranes [250], This work proved that proteins could be incorporated into hyperthick triblock copolymer membranes while maintaining their functionality as measured by membrane conductance. Incorporation of proteins in black block copolymer films has been expanded for applications in sensors [251] and protein driven energy transduction [252] across polymeric biomembranes. 

Planar polymer films (either free-standing or at interfaces) are of particular interest, not only because they are preferred in many applications, but also because they allow for surface studies which could not be performed on vesicles. Langmuir monolayers from a vesicle-forming amphiphilic triblock copolymer were studied towards understanding the polymer interactions with a cation transporting peptide, alamethicin [275]. Planar solid supported block copolymer membranes are... 

Fig. 3 Left Schematic representation of a DNA-loaded triblock-based polymersome. The virus, a X phage, binds a LamB protein and the DNA is transferred across the block copolymer membrane. Right An electron micrograph of negatively stained complexes formed between X phage and vesicles bearing LamB proteins at 37° C. The X phage (large structure on the top left comer) is attached to one vesicle via its tail. Ref. [27]. Copyright (2002) National Academy of Sciences, U.S.A...

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