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We report an interfacial approach for fabricating coordination polymer (CP) crystal films and patterns on a polymer surface using a metal ion-doped polymer substrate.

Herein, we succeeded in reproducibly synthesizing palladium nanoparticles with narrow size distribution inside metal–organic frameworks (MOFs) by using pressured H2 gas as a reductant. In addition,...

Control of structural transitions in flexible metal–organic frameworks (MOFs) on a substrate is crucial for controlling their properties for the development of MOF-based applications. In this study, we investigate the structural transition of directly formed flexible MOF crystals on a metal ion-doped polymer substrate. Utilizing hydrolyzed polymer substrates results in the formation of MOF crystals with no structural transition by the adsorption/desorption of guest molecules in their pores. Results suggest that the polymer chains of the substrate are entangled in the obtained MOF crystals, resulting in MOF crystals showing no structural transition by the adsorption/desorption of guest molecules in the pores. By controlling the temperature for the hydrolysis reaction of the polymer substrate, the number of polymer chains entangled with MOF crystals decreases, resulting in a dynamic structural transition of the resulting MOF crystals on the substrate. These results provide insights into the effect of the polymer substrate on the properties of MOF crystals on a two-dimensional substrate.

We describe a simple bottom-up strategy to generate [Au(SPh)]n (SPh: thiophenolate) coordination polymer (CP) based thin films by employing an interfacial self-assembly on a nylon substrate. This m...

We herein demonstrate a novel concept for the one-pot synthesis of metal–organic framework (MOF) films on a metal ion-doped polymer substrate based on control of the nucleation and growth processes. This strategy allows the ready fabrication of densely-packed uniform MOF films.

Highly oriented three-dimensional metal–organic framework (MOF) crystals with a pillared-layer structure were prepared on a metal ion-doped polymer substrate. This approach allowed the formation of MOF crystals with controlled crystalline orientation in a one-pot reaction facilitated by the control of the chemical interaction between the framework components and polymer substrate. Further, this approach provides a new concept for the one-pot synthesis of oriented MOF crystals and furthers the fundamental understanding of the crystal growth mechanism based on self-assembly processes on two-dimensional support substrates.

In this work, we succeeded for the first time in immobilizing an ionic liquid (IL) in a metal–organic framework (MOF) by using ion-exchange reactions. Interestingly, the resulting composites showed catalytic activities that were not observed with the original IL or the IL physically adsorbed on the MOF, implying that its ionic state was drastically changed upon immobilization.

Nickel-nanoparticle-containing polyimide composite films were prepared by liquid-phase reduction of Ni2+ ions with potassium borohydride (KBH4). The nanoparticles were amorphous with diameters of approximately 10–20 nm, depending on the KBH4 concentration and reduction temperature. At high KBH4 concentrations, the nanoparticles appeared to contain various nickel boride species. The number of nanoparticles and Ni content both increased upon repeated adsorption/reduction of Ni2+ ions, where the particle growth was inhibited by the rigid polymer chain and the formation of smaller particles was favored.

We report a new paradigm for the synthesis of metal–organic framework (MOF) crystals with controlled thickness by utilizing interfacial self-assembly of frameworks on metal ion-doped polymer precursors. The approach involves preparation of metal ion-doped polymer precursors through ion-exchange reactions and synthesis of MOF crystals by immersion into solutions containing organic ligands. The thickness of the resulting MOF crystals can be readily controlled by the number of doped-metal ions in the polymer precursors. MOF crystals could be very important and potentially useful for applications, and the present approach based on interfacial self-assembly could significantly advance MOF crystal preparation techniques.

We report a unique method for the site-selective growth of metal–organic frameworks (MOFs). The site-selective growth of MOFs can be achieved by fabricating a pattern of polymer photoresist on the metal-ion-doped polymer substrate and then constructing frameworks by immersion in an organic ligand solution.

In situ formation of Cu–Ni alloy nanoparticles with controlled composition in thin polyimide layers was investigated. The ferromagnetic properties of the nanoparticles were found to depend on the composition and the interparticle distance between the nanoparticles.

Aberrant activation of RAS signalling pathways contributes to aggressive phenotypes of cancer cells. The RAS-targeted therapies for cancer, therefore, have been recognised to be effective; however, current developments on targeting RAS have not advanced due to structural features of the RAS protein. Here, we show that expression of NRAS, a major isoform of RAS, can be controlled by photo-irradiation with an anionic phthalocyanine, ZnAPC, targeting NRAS mRNA. In vitro experiments reveal that ZnAPC binds to a G-quadruplex–forming oligonucleotide derived from the 5′-untranslated region of NRAS mRNA even in the presence of excess double-stranded RNA, which is abundant in cells, resulting in selective cleavage of the target RNA’s G-quadruplex upon photo-irradiation. In line with these results, upon photo-irradiation, ZnAPC decreases NRAS mRNA and NRAS expression and thus viability of cancer cells. These results indicate that ZnAPC may be a prominent photosensitiser for a molecularly targeted photodynamic therapy for cancer., Hyperactivity of the gene NRAS contributes to the proliferation and metastatic nature of many types of cancer cells. Here, the authors show that NRAS can be controlled by an anionic phthalocyanine coordinating Zn2+ in combination with photo-irradiation.

We describe the use of ion-exchangeable, highly cross-linked polymer films as a matrix for the synthesis of nanocomposite thin films and patterns with embedded Cu and Ni nanoparticles. We have successfully controlled the size of metal nanoparticles and thus optical and magnetic properties of the films by varying the initial amount of doped metal ions.

A synthesis method for nanocomposite microspheres containing Ni nanoparticles via chemical surface modification has been developed, by which particle size and interparticle distance for embedded Ni nanoparticles can be systematically controlled. The process relies on introduction of carboxyl acid groups via hydrolysis of matrix polymer, incorporation of Ni ions via ion exchange reaction, hydrogen-induced reduction of doped Ni ions in the sphere followed by Ni nanoparticle-catalyzed decomposition of the surrounding polymer matrix. We demonstrate the formation of Ni nanoparticles in polymer microspheres and structural change of polymer matrix upon reaction by FT-IR, SEM, and cross-sectional TEM studies, and show that initial Ni ion loading determines final nanoparticle size ranging from 3 to 8 nm, which are homogeneously distributed in the whole of the microspheres. The heat-treatment in a hydrogen atmosphere at fixed temperature causes decomposition of the polymer matrix via catalytic reaction of Ni nanopa...

Geometrically pure, all-cis poly(phenylene vinylenes) (PPVs) are synthesized by Suzuki-Miyaura-type polycondensation of 2,5-dioctyloxy-1,4-benzenediboronic acid with (Z,Z)-bis(2-bromoethenyl)benzenes, which are prepared by ruthenium-catalyzed (Z)-selective double hydrosilylation of diethynylbenzenes, followed by bromodesilylation of the resulting (Z,Z)-bis(2-silylethenyl)benzenes with N-bromosuccinimide. The all-cis PPVs thus obtained undergo one-way photoisomerization to the corresponding trans-PPVs both in solution and in the solid. This phenomenon is applied to direct microscale patterning of PPVs onto a quartz substrate.

Highly concentrated nanosized NiO particles have been prepared by means of vacuum evaporation of Ni on NH2-terminated poly(ethylene oxide) matrix film and subsequent purification by removal of a part of the matrix which was soluble in ethanol. TEM observation revealed that the purified composites contain uniformly dispersed NiO particles with an average diameter of less than 5 nm and fairly narrow size distribution. From the analyses including high-resolution TEM, electron diffraction pattern, and X-ray diffraction (XRD), the resultant particles were found to be fcc NiO, and significant lattice expansion was observed. The chemical bonding of amine end groups of the matrix molecules to NiO particle surfaces was suggested by XPS measurements. XRD and differential scanning calorimetry measurements indicate that the matrix structure in the composite is amorphous. This amorphous nature of the matrix could be caused by the restriction of molecular chain mobility through the chemical interaction between NiO part...

A new approach for the preparation of composite layers of polymide film and copper nanoparticles that relies on surface chemical modification, ion exchange, and hydrogen-induced reduction is described. Annealing in a hydrogen atmosphere after incorporation of Cu2+ ions into the modified polymide surface yields well-formed composite layers of relatively uniform thickness containing monodispersed Cu nanoparticles, accompanied by re-imidization of the modified layers.

The deposition process of iron oxyhydroxide (β-FeOOH) from aqueous solution system of FeOOH–NH 4 F·HF (aq.) with H 3 BO 3 by the liquid phase deposition (LPD) method has been investigated. The effect of initial concentration in the treatment solution and reaction time on microstructure and orientation of the deposited films were studied by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM) observation. The films deposited were constructed by small particles having a crown-like and columnar structure, depending on the concentration range in the treatment solution. XRD measurements revealed that the deposited film preferred the specific direction normal to (211) plane and the dimension of the crystallites varied with the initial concentration of the solution. The deposition process and structure of the films appeared to be strongly affected by the hydrolysis reaction of Fe 3+ ions coordinated by F − and/or partial OH − ions by adding boric acid.

The effect of composition on the dispersion of AuxCu1 − x bimetallic nanoparticles into a nylon 11 matrix has been investigated. TEM, UV–VIS, EDX, and XPS depth profiling were used for characterizing the changes in the composition of the bimetallic particles and the depth distribution of the particles in the nylon 11 layer caused by annealing in an N2 atmosphere. TEM observation and EDX analysis revealed that island-like bimetallic particles were formed on the nylon 11 surface before annealing, the composition of which was systematically controlled. Upon annealing in an N2 atmosphere, the AuxCu1 − x bimetallic particles with x ≤ 0.55 were not dispersed into the nylon 11 layer while those with x ≥ 0.70 were homogeneously dispersed in the films, indicating the existence of a critical composition for penetration of the bimetallic particles. By comparing the composition and structure of the bimetallic particles, the cause of these finding is discussed in terms of the surface free energy of the particles, which can be varied with their composition by the effect of alloying.

Gold clusters functionalized with interchain carboxylic anhydride over their entire surface have been successfully immobilized on amine-functionalized silica supports through amide-forming coupling, providing ordered two-dimensional arrangements of cluster monolayers, which might find utility in the development of artificial nanostructures for nanoelectronic device applications.

AuxCo1 − x nano-alloys with a diameter below 10 nm were fabricated via a vacuum co-evaporation method. The composition dependence and the effect of heat-treatment on the microstructure of the AuxCo1 − x nano-alloys were investigated by means of electron diffraction analysis. The lattice constant of fcc AuxCo1 − x nano-alloys varied with the composition and heat-treatment. The results revealed that as-deposited AuxCo1 − x nano-alloys were in a thermodynamically metastable state, and the following heat-treatment led to their equilibrium state. Furthermore, phase transition from fcc solid solution to L10-type ordered face-centered tetragonal (fct)-structure partially took place during heat-treatment. The temperature and magnetic field dependences of electrical resistivity were investigated for polyacrylonitrile (PAN) thin films embedded with AuxCo1 − x nano-alloys, and a TMR value of 80% was obtained at room temperature under appropriate conditions.

Composite films consisting of metallic Cu nanoparticles dispersed in poly(acrylic acid) (PAA) have been prepared by reduction of Cu2+ from the copper salt of PAA above 220 °C under a H2 atmosphere. Optical absorption properties and structures have also been investigated by UV/VIS, WAXD, TEM and IR. Spherical Cu particles were found to be homogeneously dispersed in the PAA and the diameters of the particles were in the range 10–16 nm. The composite films exhibited an optical absorption peak centered at ca. 570 nm, which was attributed to surface plasmon resonance of Cu nanoparticles. The composite film made by heat treatment at 220 °C was less stable because Cu particles in the film were oxidized to Cu2+ ions within several weeks, while the composite films prepared by heating above 230 °C were stable and the Cu particles in their films were not oxidized. The stability of the Cu nanoparticles in PAA is suggested to be related to the formation of ketone groups by condensation reactions between carboxylic acids of PAA above 230 °C.

We have prepared nylon 11 thin films containing individually isolated Au particles with various volume fractions ranging from 1.7 to 8.3% by means of a consecutive evaporation followed by heat treatment. The films obtained were characterized by TEM, XPS and UV–VIS absorption spectroscopy. Au particles were homogeneously distributed in the whole of the film after heat treatment at 100 °C for 10 min. The mean size of the Au particles increased from 3.2 to 5.2 nm in diameter upon increasing the volume fraction of Au particles. UV–VIS spectroscopy revealed that a peak position due to the surface plasmon resonance absorption of the Au particles shifted to longer wavelength as the volume fraction of the Au particles increased, accompanied by an increase of its peak intensity.

Core–satellite nanostructures made of gold nanoparticles were fabricated on glass substrates by controlled immobilization of the nanoparticles and VUV irradiation. Coupled SPR absorption between co...

A novel method is presented for the direct metallization of Cu on to surface modified polyimide resin by photochemical reduction of copper(II) ions with the aid of pre-adsorbed colloidal TiO2 as photocatalyst: for the first time copper circuit patterns are successfully fabricated simply by using a quartz-on-glass photomask without the requirement for a photoresist.

A novel technique for the direct synthesis of Si1 − xTixO2 thin films with graded composition profiles has been studied in aqueous solution, in which the (NH4)2SiF6 solutions were added into the (NH4)2TiF6 master solution under time- and rate-controlled reaction conditions: the composition of the films in the direction of the film thickness was successfully controlled over a wide range by this technique.

Small copper(I) oxide, Cu2O, particles dispersed in diamine-terminated poly(ethylene oxide) (PEO-NH2) matrices have been successfully prepared by vacuum evaporation of copper on to molten PEO-NH2, followed by heat treatment. The obtained composites were characterized by TEM, electron diffraction, viscometry, TG–DTA and FT-IR spectroscopy. The mean size of the Cu2O nanoparticles could be controlled from 2.5 to 3.5 nm in diameter by changing the amount of initial Cu deposition. The composites obtained here have a wax-like texture and are soluble in many organic solvents with no evidence for aggregation. The formation mechanism of Cu2O nanoparticles and the interaction between the nanoparticles and the matrix is also discussed.

The significant fluorescence enhancement of immobilized CdTe nanocrystals through chemical surface modifications is described, enabling us to fabricate stable, highly luminescent thin films and patterns of nanocrystal mono- and mutilayers.

The effect of DNA loadings on the thermal stability of DNA duplex immobilized on gold nanoparticles has been investigated. The modestly loaded duplexes on the gold nanoparticles showed enhanced thermal stability, as compared to that of the free duplex (without gold nanoparticles). However, the highly loaded duplex showed stability similar to that of free duplex. The stability could be controlled over a wide temperature range simply by varying the salt concentration (over 50 degrees C). Additionally, the gold nanoparticles with modestly loaded oligonucleotides could be used as nanoprobes for effective and fast strand exchange reactions, based on the increased thermal stability of the immobilized duplex. These results indicate that the interaction between the duplex and the nanoparticle surface plays an important role in determining the stability of the duplex.

We demonstrate band gap control of CdTe nanocrystals by selective surface modification using alkanethiol molecules. Both absorption and emission wavelengths can be tuned simply by mixing a dispersion of the nanocrystals with alkanethiol at room temperature, resulting in blue shifts in the optical spectra during reaction. The degree of blue shift depends on both the concentration of alkanethiols and the reaction time, thereby providing kinetic control over the emission peak wavelength of the nanocrystals in mild conditions. The observed spectral changes are suggested to be caused by a decrease in the size of the CdTe core through formation of CdTe1-x(SC10)x shells because of specific exchange of Te with alkanethiolates. The results reported herein provide a new band gap engineering scheme for semiconductor nanocrystals and offer opportunities for the design of ligand-stabilized semiconductor nanocrystals with tunable composition and optical properties.

Well-defined one-dimensional arrays of gold nanoparticles dispersed in triphenylphosphine nanowires were obtained by annealing of chloro(triphenylphosphine) gold(I) complexes in a porous alumina template. The obtained nanocomposite wires exhibit strong surface plasmon coupling due to the close proximity of adjacent gold nanoparticles.

We demonstrate site-selective chemical surface modification by dispensing potassium hydroxide solution onto polyimide, which confines source metallic ions that can subsequently be used in resist- and mask-free fabrication of copper circuit patterns. Metallization can be achieved by a wet chemical method, providing control over metal/polymer interfacial structures. Because the approach is compatible with other existing printing technologies and much simpler than conventional lithography-based methods, we propose that the present surface template method may be of general application in fabrication of metallized polymers as well as in development of integrated circuits with a variety of electronic circuit elements.

Polypyrrole-coated silver nanocomposite particles were synthesized by one-step aqueous chemical oxidative dispersion polymerization of pyrrole using silver nitrate as an oxidant. The synthesized nanocomposite particles behaved as a ‘coloured’ particulate emulsifier for the stabilization of oil-in-water emulsions.

Nano-sized copper(i) oxide particles dispersed in nylon 11 thin films have been prepared by a thermal relaxation technique. The obtained composite films were characterized by XRD, HRTEM, XPS, AES and UV-VIS absorption spectroscopy. Upon heat treatment under air, metallic copper initially deposited on the nylon 11 surface penetrates into the bulk phase of the nylon 11 as Cu2O particles. The mean size of the Cu2O particles increased from 3.2 to 6.3nm in diameter upon increasing the amount of Cu deposition. UV-VIS spectroscopy revealed that the absorption increased from as low as 600nm with increasing the size and the concentration of the dispersed Cu2O particles.

Au-dispersed TiO2(anatase) thin films have been prepared by a novel method, liquid-phase deposition (LPD). The deposited films were characterized by XRD, XPS, TEM and UV–VIS absorption spectroscopy. The results showed that the titanium oxide thin film containing AuIII ions was formed from a mixed solution of ammonium hexafluorotitanate, boric acid and tetrachloroauric acid. Heat treatment above 200 °C of the deposited film under flowing air produced dispersed Au metal particles, accompanied by the crystallization of titanium oxide as a matrix. The mean particle size of the dispersed Au particles was ca. 15 nm. The optical absorption band due to the surface plasmon resonance of the dispersed Au particles shifted toward longer wavelengths with increasing heat-treatment temperature.