Poly -b-PEO

A thiol-ene click coupling reaction can also be apphed to combine hving AROP and reversible addition-fragmentation polymerization (RAFT) techniques to yield PEO-b-poly(N-isopropylacrylamide) and PEO-h-poly(N-(2-hydroxypropyl)methacry-lamide) block copolymers (Scheme 11.5) [30]. The couphng yield of 90% was... 

A-B-C structures are another possibility to develop new properties of polymeric nanocarriers for drug release. This approach was examined for instance by Kim ef a/. [ 310 ], with PEO-PPO-PCL triblock copolymers, by Deng et al. [ 108] with PEG-b-PLLA-b-PLGA and by Gadzinowski etal. [311] with PEO-b-poly(glycidol)-b-PLLA. 

Mean-field lattice theory proved to be capable of predicting the phase behaviour of the ternary block copolymer polyethylene-b-poly(propylene oxide)-b-poly(ethylene oxide), PE-b-PPO-b-PEO in the selective solvent water [164], The ethylene block is known to be highly hydrophobic, and its hydrophobicity does not depend strongly on temperature. The difference in hydrophobicity between PPO and PEO, on the other hand, is moderate... 

Analogous alkoxides, phenoxides, and carboxylates will also initiate the ROP of epoxides, all forming propagating alkoxide species.779 Block copolymers of epoxides with /3-butyrolactone have been prepared via the addition of EO or PO to living poly(ester) chains.782 The oxygen-bound enolate of living PMMA will also react with epoxides to yield diblocks such as PEO-b-PMMA and PPO-b-PMMA (Mn= 12,800, Mw/Mn = 1.16) 787... 

PDMS-fc-PEO poly(dimethylsiloxane) -b-poly(ethylene oxide)... 

Gohy JE, Lohmeijer BGG, Alexeev A, Wang XS, Manners 1, Winnik MA, Schubert US (2004) Cylindrical micelles from the aqueous self-assembly of an amphiphilic poly(ethylene oxide)-b-poly(ferrocenylsilane) (PEO-b-PES) block copolymer with a metallo-supramolecular linker at the block junction. Chem Eur J 20 4315 323... 

Citrate-capped Au NPs have been coated with a layer composed of the double hydrophilic block copolymer polyethylene oxide)-block-poly(2-(dimethylamino)eth-yl methacrylate)-SH (PEO-b-PDMA-SH) leading to core-shell, almost spherical, Au NPs of about 18 nm. The shell cross-linking of these hybrid Au NPs gives rise to high colloidal stability [122]. 

Poly(ethylene oxide)-b-polyspermine (PEO-b-PSP) Block copolymer, primary and secondary amino groups Delivery of antisense oligonucleotides in vitro and in vivo (Kabanov etal., 1995)... 

Poly(ethylene oxide)-b-poly (L-lysine) (PEO-h-PLL) Block copolymer In vitro transfection, systemic administration of plasmids, encapsulation of oligonucleotides (Kataoka et al., 1996 Wolfert et al., 1996)... 

The technique of self-nucleation can be very useful to study the nucleation and crystallization of block copolymers that are able to crystallize [29,97-103]. Previous works have shown that domain II or the exclusive self-nucleation domain disappears for systems where the crystallizable block [PE, PEO or poly(e-caprolactone), PCL] was strongly confined into small isolated MDs [29,97-101]. The need for a very large number of nuclei in order to nucleate crystals in every confined MD (e.g., of the order of 1016 nuclei cm 3 in the case of confined spheres) implies that the amount of material that needs to be left unmolten is so large that domain II disappears and annealing will always occur to a fraction of the polymer when self-nucleation is finally attained at lower Ts. This is a direct result of the extremely high number density of MDs that need to be self-nucleated when the crystallizable block is confined within small isolated MDs. Although this effect has been mainly studied in ABC triblock copolymers and will be discussed in Sect. 6.3, it has also been reported in PS-b-PEO diblock copolymers [29,99]. 

Scheme 4.1 Chemical structures of the principal membrane, a poly(ethylene glycol)diacrylate (PEGda). b poly(ethylene oxide) (PEO). c poly(propylene glycol)diacrylate (PPGda). d 2-aminoethylmethacrylate (AEMA) hydrochloride, e poly(ethylene glycol)urethane dimethacrylate (PEGudm) [53]...

Norbornenyl-ended macromonomers from poly(ethylene oxide) (PEO), 15, as well as from PEO-b-PSt or PSt-b-PEO block copolymers, 16a, 16b, have been prepared by the initiation or termination method of living anionic polymerization [22, 23]. The ROMP of 16 afforded various types of controlled, core-shell... 

Bates and coworkers have shown the enhanced mechanical properties of polymersomes compared to liposomes evaluated from different BC systems including poly(ethylene oxide)-b-poly(ethylene) (PEO-b-PE) and poly(ethylene oxide)-h-polybutadiene (PEO-h-PB) BCs with various block compositions [72]. Moreover, the... 

Firestone et al. investigated the relationship between the molecular architecture of a series ofpoly(ethyleneoxide)-b-poly(propylene oxide) (PEO—PPO) di- and triblock copolymers and the nature of their interactions with lipid bilayers [213], The number of repeat units in the hydrophobic PPO block has been found to be a critical determinant for the polymer-lipid bilayer association. Further studies showed that temperature, polymer architecture and concentration also control the mode of interaction of PEO—PPO—PEO copolymers with lipid bilayers. Increasing either the number of repeat units in the PEO block or the polymer concentration promotes a greater degree of structural ordering [197],... 

A system with interesting properties is the poly(ethylene oxide)-Wock-poly[2-(diethylamino) ethyl methacrylalc -.sfa -[3-(trimclhoxysilyl)propyl methacrylate] (PEO-b-P(DEA-sfaf-TMSPMA)) block copolymer. This self-crosslinkable copolymer formed vesicles which demonstrated pH-tunable membrane permeability [223],... 

Fig. 14 a, b Chemical structures of a poly (ethylene glycol)-Wock-poly(a, P-aspartate) (PEG- -PAsp) and polyethylene glycol)-Wock-poly(a, P-aspartamide) (PEG-b-PAspA), b poly (ethylene oxide)-Wocfc-polystyrene-protoporphyrin IX (PEO- -PS-PPIXZn) and crystal structure of horse radish peroxidase (HRP) the arrow marks the positioning of the cofactor... 

Polyethylene oxide) and poly(N-alkylacrylamide)s are known to undergo a temperature-dependent phase change whereupon they separate from an aqueous phase at increased temperatures [14]. This inverse temperature dependence, i.e., the occurrence of a lower critical solution temperature, can be related to an entropi-cally favorable decrease in hydrogen bonding between water and the polymer with increasing temperature. In order to exploit this physical property for catalyst recovery, Bergbreiter et al. attached phosphines covalently to commercially available PEO or PEO-b-PPO-b-PEO block copolymers [Schemes 1 and 2 PPO = polypropylene oxide)] [9a],... 

Following the same line of thought. Yuan et al. [86] applied DLS to thermally responsive systems such as poly(N-isopropylacrilamide) (PNIPAM) or poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) in water. Similar to the PS/cyclohexane... 

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