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Abstract: Copper sulfides were synthesized by using the low-molecular-mass hydrogel nanofibers self-assembled from a L-glutamic acid derivative. The as-prepared copper sulfides showed a nanoribbon structure with diameter of 30–70nm and lengths of 1–10μm. The investigation of FT-IR absorption spectra and XRD pattern for the neat hydrogel and composite gel suggested that H-bonding was the main driving force to help the formation of ordered nanofibers of the hydrogel and the composite gel. The resulted mineralization indicated that the inorganic ions (Cu2+) were firstly coordinated to the carboxylate anions (COO−). With the penetration of H2S, the preformed CuS nanoparticles on the surface of the fibers acted as the growing points for the continuous growth. [Copyright &y& Elsevier]

Abstract: This paper presents a novel method for the preparation of copper sulfide (CuS) nanotubes using hydrogel based on N-lauroylalanine as template under mild condition. The resulting samples are examined by transmission electron microscopy (TEM) FT-IR spectroscopy, X-ray powder diffraction (XRD), UV–vis absorption spectroscopy. It is found that the intermolecular hydrogen bonds play an important role on the formation of the hydrogel and the Cu2+ coordination gel. The formation process of CuS nanotube is also discussed. [Copyright &y& Elsevier]

Highly stable, uniform, and monodisperse Au nanoparticles, protected by hyperbranched poly(amine-ester) (HPAE-5), were prepared by reducing HPAE-5/hydrogen tetrachloroaurate using sodium borohydride in aqueous solution. UV-visible absorption, Fourier transform infrared spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and electron diffraction (ED) have been used to study the structure and characterization of the nanocomposites. From which, it can be suggested that Au nanoparticles are formed inside HPAE-5 and located offset from the center, besides that the distribution of Au nanoparticles is narrow. The simple procedure and good results allow for a complete understanding of previous reported difficulties in preparing Au nanoparticles by wet method. [Copyright &y& Elsevier]

Two azo-containing polymers with pyrazoline group (polymers II and III) have been synthesized and their reversible optical storage properties tested in comparison with electron donor and acceptor substituted azobenzene-containing polymer I. The growth and relaxation process of birefringence signals were fit with biexponential functions. It was found that polymer II, in which azo chromophores are connected with the main chain through pyrazoline groups, has fast storage rate and good storage stability. The storage efficiency indicated that the introduction of pyrazoline groups in the polymers II and III has a positive effect. The birefringence per mole of azo chromophore showed that polymers II and III have four times the value of polymer I. The relative stability of the photoinduced birefringence decreased with the increase of temperature. [Copyright &y& Elsevier]

Au nanoparticles were prepared by reduction of HAuCl4 with NaBH4 in the presence of generation 1.5 poly(amidoamine) dendrimers with surface hydroxyl groups (OH-PAMAM-1.5). By optimizing the conditions of the preparation, stable, and uniform Au nanoparticles of 2.7±0.5 nm were obtained. UV-Vis absorption, Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and electron diffraction (ED) have been used to study the structure and characterization of the nanocomposites. From which, it could be suggested that Au nanoparticles were surrounded by OH-PAMAM-1.5 and the size distribution of Au nanoparticles is narrow. [Copyright &y& Elsevier]

A novel photochromic gel film was prepared through entrapping 12-phosphotungstic acid (PWA) into a kind of inorganic–organic matrix co-hydrolyzed from tetraethylorthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTES). Infrared (IR) spectra revealed that the Keggin structure characteristic of PW12O403− anions was present in the amine-functionalized silica gel skeleton and PWA interacted with R-NH3+ cations strongly. The amorphous state of the gel film was proved by X-ray diffraction (XRD) pattern. The gel film exhibited reversible photochromicity. Irradiated with ultraviolet light, the transparent film changes from colorless to blue. Then, bleaching occurs when the film is in contact with air or O2 in the dark. [Copyright &y& Elsevier]

A self-assembled layered superlattice composite film was fabricated by casting the chloroform solutions of ionic complex between dioctadecyldimethylammonium (DODA) and 18-molybdophosphate anion (P2Mo186−) onto CaF2, borosilicate glass, and quartz substrates. Infrared and UV spectra revealed that the Dawson structure characteristic of P2Mo186− was preserved in the composite film. A well-ordered superlattice structure was identified by X-ray diffraction (XRD). From XRD results and the cross-sectional area of DODA cation and P2Mo18 polyanion, a possible structural model was proposed. The P2Mo18/DODA film showed good photochromic properties. Irradiated with UV light, the transparent film changed from light yellow to blue. Then, bleaching occurred when the film was in contact with ambient air or O2 in the dark. A possible photochromic mechanism was proposed according to electron spin resonance (ESR), Fourier transform infrared (FTIR) spectra, and UV–Vis spectra. [Copyright &y& Elsevier]

Abstract: The photochromic process of nanocomposite film containing nanometer-sized Keggin type phosphotungstic acid uniformly dispersed in polyacrylamide matrix was studied by in situ AFM and spectroscopy. Under UV irradiation, the film was reduced photochemically to yield blue species. With the increase of irradiation time, the photoreduction proceeded from one-electron to two-electron blue stage. During the photochromism, the size and morphology of composite particles changed due to the cross-linked reactions of polymeric radicals. The XPS studies indicated that the chemical environment of tungsten changed and the W5+/W ratio increased as irradiation time prolonged. FT-IR results showed that the Keggin geometry of phosphotungstic acid was still preserved inside the composite during photochromism, and the interactions between polyanions and polymer matrix increased with the irradiation time. It was suggested that the degree of the photoreduction process depended on the varying of interactions between phosphotungstic acid and polymer. [Copyright &y& Elsevier]

A series of photochromic hybrid films were prepared through entrapping tungsten heteropolyoxometallate (PW12O403−) and molybdenum heteropolyoxometallate (PMo12O403−) in polyacrylamide (PAM) matrix, the corresponding structure and photochromic behaviors of the films were investigated with Fourier transform infrared (FT-IR), UV–Vis–near-infrared (NIR) absorption spectra (UV–Vis–NIR) and electron spin resonance (ESR). FT-IR results showed that the Keggin geometry of heteropolyoxometallate was still preserved inside the composites and strong Coulombic interaction was built between heteropolyoxometallate and PAM via hydrogen bonding. Irradiated with ultraviolet light, the transparent films changed from colorless to blue and showed reversible photochromism. The bleaching process occurred when the films were in contact with air or O2 in the dark. The molybdenum heteropolyoxometallate hybrid film had higher photochromic efficiency and slower bleaching reaction than tungsten heteropolyoxometallate hybrid film. The characteristic signals of radical and W(V) or Mo(V) in ESR spectra indicated that PAM is a hydrogen donor and the photoreduced process is in accordance with the radical mechanism. [Copyright &y& Elsevier]