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PEO Chains (peo + chain)
Selected AbstractsSynthesis, Characterization and Self-Assembly of Novel Amphiphilic Block Copolymers with a Polyhedral Oligomeric Silsesquioxanes Moiety Attached at the Junction of the Two BlocksMACROMOLECULAR RAPID COMMUNICATIONS, Issue 12 2009Liang Zhang Abstract A novel well-defined amphiphilic block copolymer, with the polyhedral oligomeric silsesquioxane (POSS) moiety at the junction of the two blocks of polystyrene and poly(ethylene oxide) (PEO), was designed and synthesized. First, a macroinitiator containing a POSS moiety and a PEO chain was prepared and then atom transfer radical polymerization of styrene was carried out in the presence of the macroinitiator in bulk. The polymerization results show that the process bears the characteristics of controlled/living free radical polymerizations. The structure and molecular weight of the polymers were characterized by GPC, 1H NMR, and FT-IR spectroscopy. The self-assembly behaviors of the polymers was investigated by TEM and SEM. It was observed that the polymers can self-assemble into vesicles in aqueous solution. [source] Synthesis of PEOlated Fe3O4@SiO2 Nanoparticles via Bioinspired Silification for Magnetic Resonance ImagingADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Happy Tan Abstract Inspired by the biosilification process, a highly benign synthesis strategy is successfully developed to synthesize PEOlated Fe3O4@SiO2 nanoparticles (PEOFSN) at room temperature and near-neutral pH. The success of such a strategy lies in the simultaneous encapsulation of Fe3O4 nanocrystals and silica precursors into the core of PEO-based polymeric micelles. The encapsulation results in the formation of a silica shell being confined to the interface between the core and corona of the Fe3O4 -nanocrystal-loaded polymeric micelles. Consequently, the surface of the Fe3O4@SiO2 nanoparticle is intrinsically covered by a layer of free PEO chains, which enable the PEOFSN to be colloidally stable not only at room temperature, but also upon incubation in the presence of proteins under physiological conditions. In addition, the silica shell formation does not cause any detrimental effects to the encapsulated Fe3O4 nanocrystals with respect to their size, morphology, crystallinity, and magnetic properties, as shown by their physicochemical behavior. The PEOFSN are shown to be good candidates for magnetic resonance imaging (MRI) contrast agents as demonstrated by the high r2/r1 ratio with long-term stability under high magnetic field, as well as the lack of cytotoxicity. [source] Solid-state stability and characterization of hot-melt extruded poly(ethylene oxide) filmsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2005Suneela Prodduturi Abstract Poly(ethylene oxide) (PEO) was used to prepare thin polymer films containing clotrimazole (CT) utilizing hot-melt extrusion (HME) technology. Films containing PEOs of two different molecular weights and the drug were investigated for solid-state characteristics, moisture-sorption, bioadhesivity, mechanical properties, release characteristics, and physical and chemical stability of the drug within the HME films. The solid-state characterization of the drug and the polymer were performed utilizing differential scanning calorimetry and X-ray diffractometry. A Texture analyzer was utilized to study the bioadhesive and mechanical properties of the HME films. Physical and chemical stability of the films, stored at 25°C/60% RH, was studied for up to 12 months. XRD profiles indicated that the drug was physically unstable (recrystallization of the drug occurred) after storage for 3 months at 25°C/60% RH. Based on the DSC studies, it has been proposed that the recrystallization of the drug may be due to the folding (due to HME) and unfolding (upon storage) of the linear PEO chains. Desirable bioadhesive, mechanical, and thermoplastic properties of PEO qualify it as a promising and potential drug carrier. However, further investigation is necessary to enhance the physical stability of these PEO,drug systems. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:2232,2245, 2005 [source] Multistimuli responsive micelles based on well-defined amphiphilic comb poly(ether amine) (acPEA)JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2010Chunfeng Di Abstract A series of well-defined amphiphilic comb poly (ether amine)s (acPEAs) were successfully synthesized through nucleophilic addition/ring-opening reaction of commercial available poly(propylene glycol) (PPO) diglycidyl ether and Jeffamine L100, followed by esterification of hydroxyl groups in backbone by alkyl carboxylic acid with different chain length. acPEAs are comprised of hydrophilic short PEO chains and hydrophobic alkyl chains as comb chains, which are grafted on PPO backbone alternately to form well-defined structure. With the very low critical micelle concentration (CMC) of around 3.0 × 10,3 g/L, the obtained acPEAs can self-assemble into stable nanomicelles, whose aggregation is responsive to temperature, pH, and ionic strength with tunable cloud point (CP). The CP of acPEAs' aqueous solution increases with the decrease of the length of graft alkyl chains, the decrease of pH value, and the decrease of ionic strength. A transition behavior in the responsive aggregation of micelles formed by acPEA8 and acPEA10 in aqueous solution, especially at low pH value (<7.0), was observed, which was also revealed by DLS results. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3468,3475, 2010 [source] Surface Grafting of PEO-Based Star-Shaped Molecules for Bioanalytical and Biomedical ApplicationsMACROMOLECULAR BIOSCIENCE, Issue 8 2007Peter Gasteier Abstract This article reviews surface grafting of star-shaped PEO. The use of star-shaped polymers is compared to linear PEO chains regarding the layer preparation and the ability of the resulting surfaces to resist protein adsorption. We then focus on the use of end-functionalized, star-shaped, PEO-based prepolymers that are able to form covalent crosslinks and functional polymer networks on the substrate. Examples are given for specific protein adsorption as well as for cell adhesion on such layers by covalent embedding of biofunctional molecules. The possibility of coating biomedically relevant polymer substrates in three-dimensional geometries is discussed and examples are shown for poly(ethylene terephthalate) monofilament constructs. [source] Supramolecular selectivity of poly(ethylene oxide) in semi-crystalline polymer nanocompositesPOLYMER INTERNATIONAL, Issue 12 2007Li Zhou Abstract Semi-crystalline polymer nanocomposites were prepared using successive meltings and recrystallizations techniques by intercalation of small guest molecules such as 4-chlorotoluene (PCT), 4-bromotoluene (PBT) and 1,4-dibromobenzene (PDBB) into poly(ethylene oxide) (PEO) crystals. Differential scanning calorimetry, Fourier transform infrared spectroscopy and wide-angle X-ray diffraction experimental results show that supramolecular selectivity exists for the PEO,PDBB/PBT ternary system, while there is no supramolecular selectivity for PEO,PCT/PBT ternary nanocomposites. The interactions between PEO chains and small guest molecules have an important influence on the polymer conformation, which results in the dramatic difference in intercalation behavior. Copyright © 2007 Society of Chemical Industry [source] | ||||||||||