Nanoreactors: Metal nanoparticles must be stabilized with carrier systems against aggregation if they are to have applications in catalysis. One such system, a thermosensitive network of poly(N-isopropylacrylamide) that surrounds polystyrene core, enables control over the catalytic activity through phase transition and leads as controllable nanoreactor. Supporting information for this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z502731_s.pdf or from...

We present a quantitative comparison of the catalytic activity palladium nanoparticles immobilized in different colloidal carrier systems, namely, (i) spherical polyelectrolyte brushes (SPB) and (ii) core−shell microgels. The first system given by SPB particles consist solid core polystyrene onto which long chains poly((2-methylpropenoyloxyethyl) trimethylammonium chloride) (PMPTAC) are grafted. These positively charged form dense layer on surface binds divalent PdCl42- ions. Reduction leads...

Selectivity in nanoreactors: A hybrid yolk–shell nanostructure that contains gold nanoparticles the core and thermosensitive microgel poly(N-isopropylacrylamide) (PNIPA) as shell is presented. The catalytic selectivity of Au-PNIPA for reduction hydrophilic 4-nitrophenol more hydrophobic nitrobenzene with NaBH4 can be tuned through volume transition PNIPA (see picture). Detailed facts importance to specialist readers are published "Supporting Information". Such documents peer-reviewed, but...

We present a study on the catalytic activity of platinum nanoparticles immobilized spherical polyelectrolyte brushes that act as carriers. The consist solid core poly(styrene) onto which long chains poly(2-methylpropenoyloxyethyl) trimethylammonium chloride are grafted. These positively charged form dense layer polyelectrolytes surface particles ("spherical brush") tightly binds divalent PtCl6-2 ions. reduction these ions within brush leads to nearly monodisperse metallic platinum. average...

We present a new system that allows us to modulate the catalytic activity of metal nanoparticles (Ag) by thermodynamic transition takes place within carrier system. Thermosensitive core−shell particles have been used as in which core consists poly(styrene) (PS), whereas shell poly(N-isopropylacrylamide) (PNIPA) network cross-linked N,N'-methylenebisacrylamide (BIS). Immersed water, these is swollen. Heating suspension above 32 °C leads volume followed marked shrinking shell. The maximum...

We describe the synthesis and solution properties of sheet- disclike Janus particles, containing an inner crosslinked polybutadiene (PB) layer two different outer sides polystyrene (PS) poly(tert-butyl methacrylate) (PtBMA). The structures formed upon adsorption flat particles onto solid substrates as well in THF are investigated. discs obtained a template-assisted synthetic pathway followed by sonication. Selectively crosslinking lamellar PB domains well-ordered microphase-separated bulk...

A controlled fabrication of wire-like assemblies cadmium sulfide (CdS) nanoparticles has been developed based on a template technique. Well-defined amphiphilic core−shell cylindrical polymer brushes were used as single molecule templates, utilizing the coordination ions with carboxylate groups in core brush. Formation CdS inside brush was carried out via reaction coordinated Cd2+ H2S. This route resulted nanoparticle about 4−5 nm diameter and 170 long. After formation nanoparticles, resumes...

Thermosensitive core-shell microgels can be used as "nanoreactors" for the immobilization of metal nanoparticles. The consist a polystyrene core and network made poly(N-isopropylacrylamide) (PNIPA) cross-linked by N,N′-methylenebisacrylamide. PNIPA shell undergoes volume transition at around 30 °C in which most water is expelled. microgel particles exhibit weak positive charge due to cationic initiator. Metal nanoparticles (such Au, Rh Pt) with high catalytic activity homogeneously embedded...

Here, we demonstrate that bimetallic Au−Pt nanorods (NRs) can be grown in situ into thermosensitive core−shell microgel particles by a novel two-step approach. In the first step, Au NRs with an average width of 6.6 ± 0.3 nm and length 34.5 5.2 (aspect ratio 0.6) were homogeneously embedded shell PNIPA networks. The volume transition network leads to strong red shift longitudinal plasmon band NRs. second platinum was preferentially deposited onto tips form dumbbell-shaped nanoparticles....

We present in-depth studies of the size tunability and self-assembly behavior Janus cylinders possessing a phase segregation into two hemicylinders. The are prepared by cross-linking lamella-cylinder morphology polystyrene-block-polybutadiene-block-poly(methyl methacrylate) block terpolymer. length can be adjusted both amplitude duration sonication treatment from micro- to nanometer length. corona biphasic particle is evidenced selective staining PS domains with RuO4 subsequent imaging....

This paper reports on the highly ordered and tunable inner structure of poly(ionic liquid) nanoparticles, which formed spontaneously by precipitation polymerization from water. Without added stabilizer, these "latexes" are much smaller (20–40 nm in diameter) than usual polymer latexes exhibit either multilamellar or unilamellar vesicular morphology, depending tail length quaternizing alkyl chains. The simplicity synthesis composition high complexity structures that resemble liposomes expand...

The thermo-reversible formation of wormlike micelles from a polystyrene-block-polyethylene-block-poly(methyl methacrylate) (PS-b-PE-b-PMMA) triblock terpolymer with crystallizable middle block in organic media is presented. rather unexpected, because PE containing diblock copolymers usually form platelet-like structures. Transmission electron microscopy (TEM) investigations revealed core−corona structure for the micelles. core formed by crystalline domains, and soluble corona exhibits...

In biomineralization, living organisms carefully control the crystallization of calcium carbonate to create functional materials and thereby often take advantage polymorphism by stabilizing a specific phase that is most suitable for given demand. particular, lifetime usually transient amorphous (ACC) seems be thoroughly regulated organic matrix, so as use it either an intermediate storage depot or directly structural element in permanently stable state. present study, we show temporal...

Membrane shapes, produced by dynamically assembled lipid/protein architectures, are crucial for both physiological functions and the design of therapeutic nanotechnologies. Here we investigate dynamics lipid membrane–neurotrophic BDNF protein complexes formation ordering in nanoparticles, with purpose innovation nanostructure-based neuroprotection biomimetic nanoarchitectonics. The kinetic pathway membrane states associated rapidly occurring nonequilibrium self-assembled nanoarchitectures...

We report the preparation of water-soluble organo-silica hybrid nanotubes templated by core-shell-corona structured triblock terpolymer cylindrical polymer brushes (CPBs). The CPBs consist a polymethacrylate backbone, poly(tert-butyl acrylate) (PtBA) core, poly(3-(trimethoxysilyl)propyl (PAPTS) shell, and poly(oligo(ethylene glycol) methacrylate) (POEGMA) corona. They were prepared via "grafting from" strategy combination two living/controlled polymerization techniques: anionic for backbone...

Abstract Calcium carbonate precipitation proceeds via a complex multistage scenario involving neutral ion clusters as precursors and amorphous phases intermediates, which finally transform to crystals. Although the existence of stable in solution prior nucleation has been demonstrated, molecular mechanisms by they precipitate are still obscure. Here, direct insight into processes that drive transformation individual nanoparticles is provided progressive colloidal stabilization different...

Extra-large nanochannel formation in the internal structure of cationic cubosome nanoparticles results from interplay between charge repulsion and steric stabilization lipid membrane interfaces is evidenced by cryogenic transmission electron microscopy (Cryo-TEM) synchrotron radiation small-angle X-ray scattering (SAXS). The swollen cubic symmetry emerges through a shaping transition onion bilayer vesicle intermediates containing fusogenic nonlamellar lipid. Cationic amphiphile particles,...

The assembly of tiny magnetic particles in external fields is important for many applications ranging from data storage to medical technologies. development ever smaller structures restricted by a size limit, where the are just barely magnetic. For such we report discovery kind solution hitherto unobserved, our knowledge. fact that occurs very relevant applications, nanoparticles either solution-processed or used liquid biological environments. Induced an field, nanocubes spontaneously...

Abstract Proteins can readily assemble into rigid, crystalline and functional structures such as viral capsids bacterial compartments. Despite ongoing advances, it is still a fundamental challenge to design synthesize protein-mimetic molecules form structures. Here we report the lattice self-assembly of cyclodextrin complexes variety capsid-like lamellae, helical tubes hollow rhombic dodecahedra. The dodecahedral morphology has not hitherto been observed in systems. spontaneously encapsulate...

Mangiferin is a natural glucosyl xanthone with antioxidant and anti-inflammatory activity, making it suitable for protection against cutaneous diseases. In this study ethosomes transethosomes were designed as topical delivery systems mangiferin. A preformulation was conducted using different surfactants in association phosphatidylcholine. Vesicle dimensional distribution monitored by photon correlation spectroscopy, while capacity cytotoxicity respectively assessed free radical scavenging...