Search

Thin films are typically bound to their substrate, limiting their integration on rough, porous, curved or chemically/thermally sensitive surfaces. Instead of employing tedious and expensive back-etching processes, specific chemical routes can enable the exfoliation of such thin structures. Herein, we demonstrate that an alkaline treatment can exfoliate a hybrid thin film comprising amorphous titania embedded in well-ordered block-copolymer micelles, which can be redeposited elsewhere. We provide sufficient evidence of the preservation of pore ordering and the importance of neutralizing the solution to spare the system from the redissolution of the titania species. [ABSTRACT FROM AUTHOR]

Here we report the soft‐template‐assisted electrochemical deposition of mesoporous semiconductors (CdSe and CdTe). The resulting mesoporous films are stoichiometrically equivalent and contain mesopores homogeneously distributed over the entire surface. To demonstrate the versatility of the method, two block copolymers with different molecular weights are used, yielding films with pores of either 9 or 18 nm diameter. As a proof of concept, the mesoporous CdSe film‐based photodetectors show a high sensitivity of 204 mW−1 cm2 at 680 nm wavelength, which is at least two orders of magnitude more sensitive than the bulk counterpart. This work presents a new synthesis route for nanostructured semiconductors with optical band gaps active in the visible spectrum. [ABSTRACT FROM AUTHOR]

Self-assembly of block copolymers (BCPs) provides a versatile strategy for controllable preparation of a broad range of functional materials with different ordered structures. In recent decades, this soft-templating strategy has been widely utilized for preparing a wide range of mesoporous materials. These porous materials have attracted tremendous interest in energy storage and conversion (ESC) applications in view of their ability to absorb, store, and interact with guest species on their exterior/interior surfaces and in the pore space. Compared with other synthetic approaches, such as template-free and hard-templating methods, BCP soft-templating protocols show great advantages in the construction of large mesopores with diameters between 10–60 nm, which are suitable for applications requiring the storage or hosting of large-sized species/molecules. In addition, this strategy shows incomparable merits in the flexible control of pore size/architecture/wall thickness, which determines the final performance of mesoporous materials in ESC devices. In the last decade, rapid development has been witnessed in the area of BCP-templated mesoporous materials. In this review paper, we overview the progress of this field over the past 10 years, with an emphasis on the discussions of synthetic methodologies, the control of materials structures (including morphology and pore size/shape), and potential applications particularly in rechargeable batteries, supercapacitors, electro-/photocatalysis, solar cells, etc. [ABSTRACT FROM AUTHOR]

Highly ordered mesoporous resol-type phenolic resin and the corresponding mesoporous carbon materials were synthesized by using poly(ethylene oxide- b-caprolactone) (PEO- b-PCL) diblock copolymer as a soft template. The self-assembled mesoporous phenolic resin was found to form only in a specific resol concentration range of 40-70 wt % due to an intriguing balance of hydrogen-bonding interactions in the resol/PEO- b-PCL mixtures. Furthermore, morphological transitions of the mesostructures from disordered to gyroid to cylindrical and finally to disordered micelle structure were observed with increasing resol concentration. By calcination under nitrogen atmosphere at 800 °C, the bicontinuous mesostructured gyroid phenolic resin could be converted to mesoporous carbon with large pore size without collapse of the original mesostructure. Furthermore, post-treatment of the mesoporous gyroid phenolic resin with melamine gave rise to N-doped mesoporous carbon with unique electronic properties for realizing high CO2 adsorption capacity (6.72 mmol g−1at 0 °C). [ABSTRACT FROM AUTHOR]

Sensing technology for biomolecules has played a key role for maintaining a high quality of life. Various kinds of sensing techniques have been developed for detecting biomolecules. Among the detection techniques which have been reported so far, non-enzymatic glucose detection, based on electrochemical mechanisms, has attracted great interest as a facile route for monitoring glucose levels in the blood. In this method, designing nanostructured electrodes is a promising strategy to improve detection performance. Owing to their fascinating physicochemical properties, including superior electrical and electrocatalytic properties, mesoporous metal films offer a wide range of useful applications which cannot be achieved by other mesoporous materials. In this work, mesoporous Au films (MpGFs) are synthesized by an effective and simple electrochemical process in the presence of a surfactant, where the mesoporous structure can be controlled by the size of the polymeric micelles. The micelles are removed using a tetrahydrofuran-based solvent-extraction method. The activity of MpGFs towards glucose oxidation is evaluated under a fixed potential in alkaline solution. Under optimal potentials, the current response for other interfering molecules is minimal, while the current response for glucose is maximal. A linear relationship between the current response and the glucose content is observed over a wide range of concentrations. Thus, our MpGF shows an excellent performance for electrochemical glucose sensing applications. [ABSTRACT FROM AUTHOR]

In this work, we report the synthesis of mesoporous nickel ferrite with an average pore size of 22 nm by using the laboratory-synthesized asymmetric polystyrene-b-polyacrylic acid-b-polyethylene oxide (PS-b-PAA-b-PEO) triblock copolymer as a soft template. Here, PS acts as a pore-forming agent, whereas PAA acts as a reaction site for the metal ions owing to its strong electrostatic interaction with positively charged metal ions. Furthermore, the PEO polymer provides stability for the micelles in solution and also promotes the orderly organization of the composite particles during assembly of the micelles. [ABSTRACT FROM AUTHOR]

Nitrogen-doped hollow carbon spheres with engineered large tunable mesoporous (∼20 nm) shells were successfully synthesized for the first time by using the colloidal silica and the diblock copolymer PS-b-PEO as the dual-template and dopamine as the precursor. The unique structural properties enable them to be promising materials as adsorbents, catalyst supports, electrode materials, drug delivery carriers and hosts for active substances. [ABSTRACT FROM AUTHOR]

Large-sized (ca. 40 nm) mesoporous Er2O3 thin films are synthesized by using a triblock copolymer poly- (styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-b-P2VP-b- PEO) as a pore directing agent. Each block makes different contributions and the molar ratio of PVP/Er3+ is crucial to guide the resultant mesoporous structure. An easy and general method is proposed and used to prepare a series of mesoporous rare-earth oxide (Sm2O3, Dy2 O3, Tb2 O3, Ho2O3, Yb2O3, and Lu2O3) thin films with potential uses in electronics and optical devices. [ABSTRACT FROM AUTHOR]

A hybrid mesoporous TiO2/Zn2Ti3O8 film with a pore size of around 40 nm is successfully synthesized by the polymeric micelle assembly approach. The chemically distinct units of polymeric micelles of the poly(styrene–2-vinylpyridine–ethylene oxide) triblock copolymer simultaneously contribute to the formation of mesoporous TiO2/Zn2Ti3O8 films with enhanced photocatalytic activity during H2 evolution reaction. [ABSTRACT FROM AUTHOR]

Herein, we report the preparation of crystalline mesoporous iron phosphate (FePO4, hereafter abbreviated as FeP) materials with 2D-plates and 1D-rods in the presence of an amphiphilic block copolymer (F127), iron nitrate, and phosphoric acid. The dimensionality of mesoporous FeP can be switched by changing the polarity of the synthetic medium. [ABSTRACT FROM AUTHOR]

A facile method for the fabrication of well-dispersed mesoporous Pt nanospheres involves the use of a polymeric micelle assembly. A core-shell-corona type triblock copolymer [poly(styrene- b-2-vinylpyridine- b-ethylene oxide), PS- b-P2VP- b-PEO] is employed as the pore-directing agent. Negatively charged PtCl42− ions preferably interact with the protonated P2VP+ blocks while the free PEO chains prevent the aggregation of the Pt nanospheres. The size of the mesopores can be finely tuned by varying the length of the PS chain. Furthermore, it is demonstrated that the metallic mesoporous nanospheres thus obtained are promising candidates for applications in electrochemistry. [ABSTRACT FROM AUTHOR]

Here we propose a novel way to construct mesoporous architectures through evaporation-induced assembly of polymeric micelles with crystalline nanosheets. As a model study, we used niobate nanosheets exfoliated by the direct reaction of K4Nb6O17⋅3 H2O crystals with an aqueous solution of propylamine. The electrostatic interaction between negatively charged nanosheets and positively charged polymeric micelles enable us to form composite micelles with the nanosheets. Removal of the micelles by calcination results in robust mesoporous oxides with the original crystalline structure. [ABSTRACT FROM AUTHOR]

Core-corona inversion of micelles of diblock copolymer poly(acrylic acid)- block-poly(N-isopropylacrylamide) (PAA- b-PNIPAM), has been successfully realized by switching either pH or temperature. The strong interaction of doxorubicin with the PAA block and the pH-sensitive drug release from the polymer make the system very useful as a controlled drug delivery system. The encapsulation of hydrophobic Nile Red molecules above the lower critical solution temperature of PNIPAM suggests that this polymer may be useful for removing hydrophobic pollutants. [ABSTRACT FROM AUTHOR]

A triblock copolymer, poly(styrene-b-2-vinyl pyridine- b-ethylene oxide) (PS-b-P2VP-b-PEO) was used as a soft template to synthesize large-sized mesoporous phosphosilicate thin films. The kinetically frozen PS core stabilizes the micelles. The strong interaction of the inorganic precursors with the P2VP shell enables the fabrication of highly robust walls of phosphosilicate and the PEO helps orderly packing of the micelles during solvent evaporation. The molar ratio of phosphoric acid and tetraethyl orthosilicate is crucial to achieve the final mesostructure. The insertion of phosphorus species into the siloxane network is studied by 29Si and 31P MAS NMR spectra. The mesoporous phosphosilicate films exhibit steady cell adhesion properties and show great promise as excellent materials in bone-growth engineering applications. [ABSTRACT FROM AUTHOR]

Fit to print: This work describes a novel vapor‐phase synthesis system to directly replicate mesoporous silica films from block copolymer films without phase transitions (see figure). [ABSTRACT FROM AUTHOR]

Polymeric micelles with core–shell–corona nanoarchitecture were designed for intracellular therapeutic anti-cancer drug carriers. Poly(styrene-b-acrylic acid-b-ethylene glycol) (PS-b-PAA-b-PEG) asymmetric triblock copolymer underwent self-assembly in aqueous solution to form spherical micelles with hydrophobic PS core, anionic PAA shell and hydrophilic PEG corona. The anti-cancer drug (doxorubicin, DOX) was successfully incorporated into the polymeric micelles. The in vitro release experiment confirmed that the release of DOX from the micelles was inhibited at pH 7.4. In contrast, an accelerated release of DOX was observed at mildly acidic conditions such as pH 4.5. The excellent biocompatibility of our PS-b-PAA-b-PEG-based micelles made the synthesized nano-carrier best suited for the delivery of anti-cancer drugs. [ABSTRACT FROM AUTHOR]

Mesoporous titania (TiO2) thin films are prepared by a spin-coating method using new laboratory-made polystyrene- block-polybutadiene- block-polystyrene-based triblock copolymers in which the polystyrene block is functionalized with hydrophilic sulfonic groups (abbreviated as sulfonated HmSEBmS). The polymer used in this study is more thermally stable than commercial Pluronic-type block copolymers (e.g. P123 and F127). As-prepared TiO2 thin films are calcined under various temperatures. The calcined films are systematically characterized by low-angle and wide-angle XRD, scanning electron microscopy (SEM), and nitrogen gas adsorption-desorption isotherms. As calcination temperatures increase, crystal growth proceeds in the pore walls and the phase transformation from anatase to rutile occurs. Even after calcination at 550 and 600 °C, the thin films nicely preserve high surface areas. On the other hand, the surface areas of mesoporous TiO2 prepared from P123 are markedly decreased after calcination at 550 °C. [ABSTRACT FROM AUTHOR]

Mesoporous alumina films with large-sized cage-type mesopores were prepared by using commercially available diblock copolymer (PS- b-PEO) and economic inorganic salt (AlCl3) as aluminum source. The obtained mesopore sizes drastically expand from 35 nm to 80 nm when the amount of ethanol in the precursor solutions were controlled. More interestingly, under an optimized amount of ethanol as co-solvent, there was no significant change of micelle morphology on the substrate, even though the relative amount of PS- b-PEO to alumina source was dramatically varied. When the amount of alumina precursor was decreased, the pore walls gradually became thinner, thereby improving pore connectivity. The ordered mesoporous alumina films obtained in this study exhibit high thermal stability up to 1000 °C, and their frameworks are successfully crystallized to γ-alumina phase. This technique could also be applicable for creating other metal oxide thin films with large mesopores. [ABSTRACT FROM AUTHOR]

Here we report the preparation of highly ordered mesoporous alumina films existing both as P63/mmcand Fm-3mmesostructures by using triblock copolymer Pluronic P123 as the structure-directing agent. 2D grazing-incidence small-angle X-ray scattering (GI-SAXS) completely proves the existence of two different mesopore structures (i.e., [001]-oriented P63/mmcand [111]-oriented Fm-3msymmetries). After calcination at 1000 °C, the amorphous alumina framework is successfully converted to γ-alumina crystals. During the crystallization process, large uniaxial shrinkage occurs along the direction perpendicular to the substrate with the retention of horizontal mesoscale periodicity, thereby resulting in formation of partially vertical mesoporosity in the film. Through detailed electron microscopic study, we discuss the formation mechanism for the vertical mesoporosity upon calcination. The obtained mesoporous γ-alumina film shows high thermal stability up to 1000 °C, which is highly useful in wide research areas such as catalyst supports and separators. [ABSTRACT FROM AUTHOR]

We report the synthesis of hydroxyapatite nanoparticles (HANPs) by the coprecipitation method using calcium D-gluconate and potassium hydrogen phosphate as the sources of calcium and phosphate ions, respectively, and the triblock copolymer F127 as a stabilizer. The HANPs were characterized using scanning electron microscopy, x-ray diffraction, and nitrogen adsorption/desorption isotherms. Removal of F127 by solvent extraction or calcination alters the structure of HANPs. The solvent-extracted HANPs were single crystals with their h001i axis oriented along the rod axis of the HANP, whereas the calcined HANPs contained two crystal phases that resulted in a spherical morphology. The calcined HANPs had much higher surface area (127m2 g-1) than the solvent-extracted HANPs (44m2 g-1). [ABSTRACT FROM AUTHOR]

We report the synthesis of mesostructured Pt films with extralarge periodicity from lyotropic liquid crystals consisting of block copolymers (polystyrene-b-polyethylene oxide, PS-b-PEO) on Au substrates by electrochemical deposition. The Pt films with three types of (two-dimensional (2D)-hexagonal, lamellar, and cage-type) mesostructures are successfully synthesized by controlling the compositional ratio between block copolymers and Pt species in precursor solutions. The mesostructured Pt films have high electrochemically active surface areas. The bumpy mesopore surfaces, which reflect the mesopore walls consisting of connected nanoparticles, greatly contribute to the enhancement of the surface areas. The mesopore walls have single crystal domains over 400 nm² region proved by the lattice fringes of Pt extending over several nanoparticles. [ABSTRACT FROM AUTHOR]

We report block copolymer assisted synthesis of a Au metal core coated with a nanodendritic Pt shell (Au@Pt). Herein, a rapid, one-step and efficient wet-chemical route is proposed to straightforwardly synthesize Au@Pt with high yield (∼100%), which was mediated by Pluronic F127 block copolymer from the reduction of Pt and Au complexes by ascorbic acid (AA). [ABSTRACT FROM AUTHOR]

Spray-drying of clear precursor solution containing inorganic-organic hybrid species and EOnPOmEOn triblock copolymer at low temperature, followed by treatment in acetone to remove the triblock copolymer, afforded spherical particles of aluminium organophosphonate (AOP) with uniform mesopores. [ABSTRACT FROM AUTHOR]

The article presents a study which describes the block copolymer mediated synthesis of dendritic platinum nanoparticles (DPN). It states that pluronic F127 molecules also played a structure-directing agent role besides action as a protecting agent. The study revealed that DPN were straightforwardly synthesized in high yield via a one-step aqueous-phase reaction mediated by block copolymer under mild conditions.

A polymeric micelle assembly is used for the fabrication of well‐dispersed mesoporous Pt nanospheres by Y. Yamauchi, B. P. Bastakoti et al. in their Communication on page 11073 ff. A core–shell–corona triblock copolymer [poly(styrene‐b‐2‐vinylpyridine‐b‐ethylene oxide), PS‐b‐P2VP‐b‐PEO], is employed as the pore‐directing agent. The negatively charged Pt species preferably interact with the protonated P2VP blocks, while the free PEO chains prevent the aggregation of the Pt nanospheres. [ABSTRACT FROM AUTHOR]

The back cover of the volume 54, number 14 issue of the journal "Angewandte Chemie International Edition" is presented.

• A facile preparation of an ultrathin, highly graphitized carbon nanosheets framework is reported. • A gel composite of resol, FeCl 3 ·6H 2 O, and block polymer was prepared by ball milling process. • FeCl 3 ·6H 2 O in the resol-F127-Fe composite benefits the formation of graphene-like structure. • F127 helps to form the porous architecture with interconnected framework of carbon nanosheet. • The prepared 3D carbon shows excellent electrochemical performance in lithium-ion batteries. Constructing two-dimensional (2D) carbon nanosheets into a three-dimensional (3D) framework can prevent restacking and increase the accessible surface area, which is promising to broaden the range of applications of 2D carbon materials. Here we report a facile preparation of an ultrathin, highly graphitized carbon nanosheets framework (UGCF) by directly carbonizing a gel composite of resol, FeCl 3 ·6H 2 O, and F127 block polymer prepared by ball milling. During the carbonization process, the presence of FeCl 3 ·6H 2 O in the resol-F127-Fe composite benefits the formation of highly graphitized structure, while F127 helps to introduce the porous architecture, resulting in an interconnected framework of carbon nanosheets. The unique carbon nanostructure of this UGCF has major advantages for electrochemical applications, owing to the large accessible geometrical surface, the rapid diffusion paths for ions, and the continuous transfer path for electrons through the graphitic framework. When used as anode in lithium-ion batteries, the UGCF shows excellent electrochemical performance in terms of capacity, rate performance, and cycle stability. This work provides a convenient and simple scale-up method to prepare highly graphitized carbon nanosheets with 3D nanoarchitecture. [ABSTRACT FROM AUTHOR]

In this work, we report the soft-templated preparation of mesoporous nickel oxide using an asymmetric poly(styrene- block -acrylic acid- block -ethylene glycol) (PS- b -PAA- b -PEG) triblock copolymer. This block copolymer forms a micelle consisting of a PS core, a PAA shell and a PEG corona in aqueous solutions, which can serve as a soft template. Specifically, the PS block forms the core of the micelles on the basis of its lower solubility in water. The anionic PAA block interacts with the cationic Ni 2+ ions present in the solution to generate the shell. The PEG block forms the corona of the micelles and stabilizes the micelles by preventing secondary aggregation through steric repulsion between the PEG chains. In terms of textural characteristics, the as-synthesized mesoporous NiO exhibits a large average pore size of 35 nm with large specific surface area and pore volume of 97.0 m 2  g −1 and 0.411 cm 3  g −1 , respectively. It is expected that the proposed soft-templated strategy can be expanded to other metal oxides/sulfides in the future for potential applications in gas sensors, catalysis, energy storage and conversion, optoelectronics, and biomedical applications. [ABSTRACT FROM AUTHOR]

We report self-assembly of double hydrophilic block copolymer poly(acrylic acid- b - N -isopropylacrylamide) in aqueous solution. Self-assembly of calcium ions chelated complex micelles upon mineralization reaction forms calcium carbonate (CaCO 3 ) sphere. High porosity on CaCO 3 spheres can accommodate a large amount of anticancer drug (doxorubicin) and achieve sustainable drug release. [ABSTRACT FROM AUTHOR]

We report a simple and facile method for the formation of mesopores inside Pt nanospheres using double hydrophilic block copolymer poly(ethylene oxide- b -vinylpyridine) as template and structure directing agent. The dissolved Pt species strongly interact with the vinylpyridine and ethylene oxide units. The reduction of the Pt species in the presence of polymeric micelles leads to the formation of uniform mesoporous Pt nanospheres. fx1 [ABSTRACT FROM AUTHOR]

We report the synthesis of bimetallic Pt-Pd nanoparticles by simultaneous reduction of platinum acetylacetonate and sodium tetrachloropalladate using N,N-dimethylformamide as both solvent and reductant through a solvothermal method. A triblock copolymer, poly(styrene- b -2-vinyl pyridine- b -ethylene oxide), works as a structure directing agent to control the morphology of the nanoparticles by preventing the self-aggregation of small nanocrystals. The homogeneous Pt-Pd nanoparticles exhibit an enhanced electrocatalytic activity and stability compared with commercial Pt black. [ABSTRACT FROM AUTHOR]

Here we report the synthesis of mesoporousmetal oxide materialswith various compositions by assembly of spherical polymeric micellesconsisting of triblock copolymer poly(styrene-b-2-vinylpyridine-b-ethylene oxide) (PS-b-PVP-b-PEO) with three chemically distinct units.The PVP block interacts strongly with the inorganic precursors forthe target compositions. The hydrophobic PS block is kinetically frozenin the precursor solutions, enabling the spherical micelles to remainin a stable form. The frozen PS cores serve as templates for preparingrobust mesoporous materials. The PEO corona helps the micelles tostay well dispersed in the precursor solutions, which plays a keyrole in the orderly arrangement of the micelles during solvent evaporation.This approach is based on assembly of the stable micelles using asimple, highly reproducible method and is widely applicable towardnumerous compositions that are difficult for the formation of mesoporousstructures. [ABSTRACT FROM AUTHOR]