PEO-PPO block copolymers

Tan, J. S., D. E. Butter eld, C. L. Voycheck, K. D. Caidwell, and J. T. Li. 1993. Surface modi cation of nanoparticles by PEO/PPO block copolymers to minimize interactions with blood components and prolong blood circulation in rat iomaterials14 823-833. 

Though 85% of the amino acid residues in the SF protein are compact with small side chains (glycine, alanine, and serine), near both the N- and C-termini of the SF chain, several quite bulky amino acid residues (proline, histidine, trypthophan) are present in the SF primary structure [100], At first glance, the possibility that y-CDs (9-10A channel diameter) have completely threaded over SF protein chains to form the SF-y-CD IC seems unlikely. However, there is precedence for such an observation in the study of the complexation of propylene oxide-fe-ethylene oxide-fe-propylene oxide (PPO-PEO-PPO) block copolymer with a-CD [101], As pointed out in this study, PPO and PEO homopolymers are known to form CD-ICs only with (3- and a-CDs, respectively. Nevertheless, it was observed there that a-CDs are able to thread over the bulkier PPO end-blocks and complex with the central PEO... 

R Alexandridis, U. Olsson, P, Linse, B. Lindman, Structural polymorphism of amphiphilic block copolymers in mixtures with water and oil Comparison with solvent-free block copolymers and surfactant systems. In Amphiphilic Block Copolymers. Self-Assembly and Applications, Ed. P. Alexandridis, U. Olsson, B. Lindman, p. 169, Elsevier, Amsterdam (2000) (overview over the phase behavior of PEO-PPO block copolymers). 

Pluronic-coated carbon nanotubes The applicability of carbon nanotubes for neural tissue engineering was further proved by Bardi et al. (2009), wherein the carbon nanotubes when coated with Pluronic F127 (PF127), a PPO-PEO-PPO block copolymer, showed more distinctive biocompatibility properties than the individual components. The researchers proposed that PF127 stabilized and solubilized the CNTs due to its surfactant action, whereas CNTs circumvented the PF127-induced apoptosis by the so-called surfactant sequestration mechanism (Bardi et al., 2009). 

PEO-based copolymers have received much attention. In this respect, PEO-PPO and PEO-PPO-PEO Pluronic copolymers were investigated in organic solvents such as formamides, as illustrated by the works of Lindmann and coworkers and Alexandridis et al. [92-94], However, the formation of reverse micelles in organic solvents from PEO-based block copolymers has been shown to be a complex phenomenon due to the ability of PEO to crystallize. 

Recent studies on PEO-PPO, PEO-PBO di- and triblock copolymers include the works of Bahadur et al. [121], who examined the role of various additives on the micellization behavior, of Guo et al. [122], who used FT-Raman spectroscopy to study the hydration and conformation as a function of temperature, of Booth and coworkers [ 123], who were mainly interested in PEO-PBO block copolymers with long PEO sequences, and of Hamley et al., who used in situ AFM measurements in water to characterize the morphology of PEO-PPO micelles [56,57]. 

Polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) (Pluronic) block copolymer is a very efficient reducing agent and nanoparticle stabilizer. Au NPs of about 10 nm can be stabilized with PEO-PPO-PEO block copolymer solutions in water and at room temperature and using HAuC14 as precursor. The formation of gold nanoparticles is controlled by the overall molecular weight and relative block length of the block copolymer [118]. 

TPS may be regarded as an extension of ABS in that it substitutes thermosetting polymers for the polymer-polymer or polymer-salt systems of the latter (see, e.g., Johansson et al., 1998 Persson et al., 1998). Examples of the polymers used are poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), PEO-PPO block polymers (Ploronic) and PEO-PPO random copolymers (UCON) (Hurter et al., 1995). This technique is particularly relevant in organic synthesis since it can be used in the production of pharmaceuticals (Alexandridis et al., 1994 Lopes and Loh, 1998). 

L. Xu, et al., Synthesis, characterization, and self-assembly of linear poly(ethylene oxide)-block-poly (propylene oxide)-block-poly(e-caprolactone) (PEO-PPO-PCL) copolymers. J. Colloid Interface Sci. 393 (2013) 174-181, doi 10.1016/j.jcis.2012.10.051. 

Self-assembly of block copolymers that are made of poly(ethylene oxide), PEO, as the hydrophilic non-ionic block, has been extensively explored. The research interest in PEO-containing block copolymers was motivated, to a great extent, by potential biomedical applications, which rely on the finding that PEO moieties are biocompatible. Because amphiphilic block copolymers of PEO and poly(propylene oxide) PPO (pluronics) are produced on an industrial scale, research on these nonionic polymeric surfactants resulted in many technological applications. Both PPO and PEO are thermoresponsive, having a low solution critical temperature (LSCT),... 

Block copolymers combine different physical or/and chemical properties in one polymer. Hence, some new properties (e.g., amphiphUicity) can be achieved for this type of polymer. Because of their unique properties, copolymers are used everywhere in everyday life. For example, poly(ethylene oxide) (PEO) and poly(propyl-ene oxide) (PPO) block copolymers (PEO-PPO-PEO, commercially known as Pluronics) are widely used as nonionic surfactants in daily care products. One commercial thermoplastic elastomer is made from styrene-butadiene-styrene (SBS) triblock copolymers. 

Block copolymers are introduced into the PEO chain to reduce its regularity. For example, with PS-PEO-PPO block polymer, both the ionic conductivity and the mechanical performance of the prepared electrolytes are better than those of normal PEO because PS and PPO blocks destroy the crystallites in PEO and improve the mechanical strength. Linear block copolymers formed with siloxanes have amorphous structures and the Li+-ionic conductivity can be nearly two orders of magnitude higher. The Tg of the compounds shown in Figure 10.16a and b are -60°C and -123°C, respectively. In the case of their polymer electrolytes formed with LiC104, the ionic conductivities at room temperature are 1.5 x 10 and 2.0 x 10 S/cm, respectively. 

Two PEO-PPO-PEO three-block copolymers of the Synperonic series - F108 and P104 [28, 29] - have been employed. PPO represents the middle hydrophobic block B and both hydrophilic PEO form the two terminal chains A. These commercial, non-ionic, water-soluble polymeric surfactants were used as obtained from BASF. They are pure though not monodisperse. The molecular masses and average EO/PO contents are known from the manufacturer and yield approximate... 

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