Interaction of metal compounds with ‘double-hydrophilic’ block copolymers in aqueous medium and metal colloid formation

Bronstein, Lyudmila M.; Sidorov, Stanislav N.; Gourkova, A.Y.; Valetsky, Pyotr M.; Hartmann, J.; Breulmann, Michael; Cölfen, Helmut; Antonietti, Markus

doi:10.1016/s0020-1693(98)00208-4

Cited by 140 publications

(141 citation statements)

References 28 publications

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“…The molecular weight of the copolymer is on the order of 100 kg. 12 Increasing salt concentration increases the number of nucleation sites, namely particle density on the fibers.…”

Section: Discussionmentioning

confidence: 99%

“…11 A number of studies were performed to synthesize noble metal particles of different elements starting from micellization of polymeric templates in aqueous medium. 12,13 The important key factor of this method is to synthesize a soluble copolymer making micellar 13 or dendritic 12 structures which have enough space at the core for smaller metal salt molecules. Following the reduction process of the metal salt, uniform sized stable metal nanoparticles were formed.…”

Section: Introductionmentioning

confidence: 99%

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Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Demir¹,

Gülgün²,

Menceloǵlu³

et al. 2004

Macromolecules

284

172

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Catalytic palladium (Pd) nanoparticles on electrospun copolymers of acrylonitrile and acrylic acid (PAN-AA) mats were produced via reduction of PdCl2 with hydrazine. Fiber mats were electrospun from homogeneous solutions of PAN-AA and PdCl2 in dimethylformamide (DMF). Pd cations were reduced to Pd metals when fiber mats were treated in an aqueous hydrazine solution at room temperature. Pd atoms nucleate and form small crystallites whose sizes were estimated from the peak broadening of X-ray diffraction peaks. Two to four crystallites adhere together and form agglomerates. Agglomerate sizes and fiber diameters were determined by scanning and transmission electron microscopy. Spherical Pd nanoparticles were dispersed homogeneously on the electrospun nanofibers. The effects of copolymer composition and amount of PdCl 2 on particle size were investigated. Pd particle size mainly depends on the amount of acrylic acid functional groups and PdCl2 concentration in the spinning solution. Increasing acrylic acid concentration on polymer chains leads to larger Pd nanoparticles. In addition, Pd particle size becomes larger with increasing PdCl 2 concentration in the spinning solution. Hence, it is possible to tune the number density and the size of metal nanoparticles. The catalytic activity of the Pd nanoparticles in electrospun mats was determined by selective hydrogenation of dehydrolinalool (3,7-dimethyloct-6-ene-1-yne-3-ol, DHL) in toluene at 90°C. Electrospun fibers with Pd particles have 4.5 times higher catalytic activity than the current Pd/Al 2O3 catalyst.

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“…The molecular weight of the copolymer is on the order of 100 kg. 12 Increasing salt concentration increases the number of nucleation sites, namely particle density on the fibers.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Demir¹,

Gülgün²,

Menceloǵlu³

et al. 2004

Macromolecules

284

172

View full text Add to dashboard Cite

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“…Under physiological salt concentration, however, the ionically stabilized GNPs tend to aggregate because of charge shielding. To improve their dispersibility in solutions with appreciably high ionic strength, various types of low-molecular-weight stabilizers, as well as water-soluble polymers such as starches, are often added to the solution [27]. An alternative way to stabilize such a dispersion is to form a brushed layer of hydrophilic polymer strands on the surface of the GNPs.…”

Section: Introductionmentioning

confidence: 99%

“…An alternative method was proposed using water-soluble polymers possessing coordination ability with metal surfaces, such as poly(2-vinylpyridine) and poly(ethyleneimine), as stabilizers for metal colloids [27,36]. To improve the long-term stability of PEGylated GNPs under physiological conditions, we have used PEG-b-polyamine block copolymers.…”

Section: Introductionmentioning

confidence: 99%

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

Nagasaki

2010

Science and Technology of Advanced Materials

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A poly(ethylene glycol)-b-poly [2-(N,N-dimethylamino)ethyl methacrylate] block copolymer possessing a reactive acetal group at the end of the poly(ethylene glycol) (PEG) chain, that is, acetal-PEG-b-PAMA, was synthesized by a proprietary polymerization technique. Gold nanoparticles (GNPs) were prepared using the thus-synthesized acetal-PEG-b-PAMA block copolymer. The PEG-b-PAMA not only acted as a reducing agent of aurate ions but also attached to the nanoparticle surface. The GNPs obtained had controlled sizes and narrow size distributions. They also showed high dispersion stability owing to the presence of PEG tethering chains on the surface. The same strategy should also be applicable to the fabrication of semiconductor quantum dots and inorganic porous nanoparticles. The preparation of nanoparticles in situ, i.e. in the presence of acetal-PEG-b-PAMA, gave the most densely packed polymer layer on the nanoparticle surface; this was not observed when coating preformed nanoparticles. PEG/polyamine block copolymer was more functional on the metal surface than PEG/polyamine graft copolymer, as confirmed by angle-dependent x-ray photoelectron spectroscopy. We successfully solubilized the C 60 fullerene into aqueous media using acetal-PEG-b-PAMA. A C 60 /acetal-PEG-b-PAMA complex with a size below 5 nm was obtained by dialysis. The preparation and characterization of these materials are described in this review.

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“…24 The polymer has a high content of amine nitrogen able to donate electrons and coordinate with transition metal ions. 25,26 This property may be applied for the immobilization of proteins and enzymes, [27][28][29] anchoring metal nanoparticles, 30 or drug delivery. 31,32 Different authors have reported ionomer complex micelles of PEI grafted with methoxypolyethylene glycol (mPEG) and anionic surfactants, 9,33 metal ions (AuCl 3 or PtCl 6 2-), 26,34 oligonucleotides, 35 or plasmid DNA.…”

Section: +mentioning

confidence: 99%

Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

Abolmaali¹,

Tamaddon²,

Yousefi³

et al. 2014

IJN

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A functional polycation nanonetwork was developed for delivery of water soluble chemotherapeutic agents. The complexes of polyethyleneimine grafted methoxy polyethylene glycol (PEI-g-mPEG) and Zn 2+ were utilized as the micellar template for cross-linking with dithiodipropionic acid, followed by an acidic pH dialysis to remove the metal ion from the micellar template. The synthesis method was optimized according to pH, the molar ratio of Zn 2+ , and the cross-link ratio. The atomic force microscopy showed soft, discrete, and uniform nano-networks. They were sensitive to the simulated reductive environment as determined by Ellman’s assay. They showed few positive ζ potential and an average hydrodynamic diameter of 162±10 nm, which decreased to 49±11 nm upon dehydration. The ionic character of the nano-networks allowed the achievement of a higher-loading capacity of methotrexate (MTX), approximately 57% weight per weight, depending on the cross-link and the drug feed ratios. The nano-networks actively loaded with MTX presented some suitable properties, such as the hydrodynamic size of 117±16 nm, polydispersity index of 0.22, and a prolonged swelling-controlled release profile over 24 hours that boosted following reductive activation of the nanonetwork biodegradation. Unlike the PEI ionomer, the nano-networks provided an acceptable cytotoxicity profile. The drug-loaded nano-networks exhibited more specific cytotoxicity against human hepatocellular carcinoma cells if compared to free MTX at concentrations above 1 μM. The enhanced antitumor activity in vitro might be attributed to endocytic entry of MTX-loaded nano-networks that was found in the epifluorescence microscopy experiment for the fluorophore-labeled nano-networks.

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Interaction of metal compounds with ‘double-hydrophilic’ block copolymers in aqueous medium and metal colloid formation

Cited by 140 publications

References 28 publications

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

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Interaction of metal compounds with ‘double-hydrophilic’ block copolymers in aqueous medium and metal colloid formation

Cited by 140 publications

References 28 publications

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl2 Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl2 Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

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Product

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Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity

Palladium Nanoparticles by Electrospinning from Poly(acrylonitrile-co-acrylic acid)−PdCl₂ Solutions. Relations between Preparation Conditions, Particle Size, and Catalytic Activity