Ethylene oxide , polymer brushes

Keywords Chitosan Graft copolymers Poly(ethylene oxide) Polymer brushes Surface forces... 

Recently, Quirk and Mathers [264] performed LASIP of isoprene on silicon wafers. A chlorodimethylsilane-functionalized diphenylefhene (DPE) was coupled onto the surface and lithiated with n-BuLi to form the initiating species. The living poly(isoprene) (PI) was end- functionalized with ethylene oxide. A brush thickness of 5 nm after two days of polymerization (9.5 nm after four days) was obtained in contrast to a polymer layer thickness of 1.9 nm by the grafting onto method using a telechelic silane functionahzed PI. 

So far, there have been only few reports about the synthesis of amphipolar polymer brushes, i.e. with amphiphilic block copolymer side chains. Gna-nou et al. [115] first reported the ROMP of norbornenoyl-endfunctionalized polystyrene-f -poly(ethylene oxide) macromonomers. Due to the low degree of polymerization, the polymacromonomer adopted a star-like rather than a cylindrical shape. Schmidt et al. [123] synthesized amphipolar cylindrical brushes with poly(2-vinylpyridine)-block-polystyrene side chains via radical polymerization of the corresponding block macromonomer. A similar polymer brush with poly(a-methylstyrene)-Wocfc-poly(2-vinylpyridine) side chains was also synthesized by Ishizu et al. via radical polymerization [124]. Using the grafting from approach, Muller et al. [121, 125] synthesized... 

The polymer most commonly used to prepare brushes is poly (ethylene oxide) (PEO), which is alternatively called poly (ethylene glycol)(PEG). This is primarily because in an aqueous environment PEO molecules are highly mobile22 and strongly hydrated, attaining large exclusion volumes.23 Furthermore, PEO is biocompatible.24 Sometimes the role of polysaccharides to prevent bioadhesion is reported.25... 

A. Roosjen, H. C. van der Mei, H. J. Busscher, and W. Norde, Microbial adhesion to poly (ethylene oxide) brushes influence of polymer chain length and temperature, Langmuir 20, 10949-10955 (2004). 

Barentin C, Muller P, Joanny JF (1998) Polymer brushes formed by end-capped poly(ethylene oxide) (PEO) at the air-water interface. Macromolecules 31 2198-2211... 

Zhou Y, Lledberg B et al (2007) Chitosan-N-poly (ethylene oxide) brush polymers for reduced nonspecific protein adsorption. J Colloid Interface Sci 305 62-71... 

Busscher HJ, Kaper HJ, Norde W. 2003. Characterization of poly(ethylene oxide) brushes on glass surfaces and adhesion of Staphylococcus epidermidis. J Biomater Sci Polym Ed 74 313-324. 

Tsarevsky has found that hypervalent iodine compounds can be used for the direct azidation of polystyrene and consecutive click-type functionalization [49]. In particular, polystyrene can be directly azidated in 1,2-dichloroethane or chlorobenzene using a combination of trimethylsilyl azide and (diacetoxyiodo)benzene. 2D NMR HMBC spectra indicate that the azido groups are attached to the polymer backbone and also possibly to the aryl pendant groups. Approximately one in every 11 styrene units can be modified by using a ratio of PhI(OAc)2 to trimethylsilyl azide to styrene units of 1 2.1 1 at 0 °C for 4 h followed by heating to 50 °C for 2 h in chlorobenzene. The azidated polymers have been further used as backbone precursors in the synthesis of polymeric brushes with hydrophilic side chains via a copper-catalyzed click reaction with poly(ethylene oxide) monomethyl ether 4-pentynoate [49],... 

Leckband D, Sheth S, Halperin A. Grafted poly(ethylene oxide) brushes as nonfouUng surface coatings. J Biomater Sci Polym Ed 1999 10(10) 1125 7. 

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