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In this study, we report a facile method to fabricate silica-silver (SiO2/ PG-Fe3+/Ag) core–shell composite microspheres. The surface of SiO2 microspheres is functionalized with pyrogallol-ferric ions (PG-Fe3+) complexes, then Ag ions are reduced to Ag nanoparticles in situ onto the surface of SiO2 microspheres by electroless plating process. The Ag nanoparticles were uniformly coated on the surface of the SiO2 microspheres and formed a distinctive layer, which was confirmed by scanning electron microscopy characterization. The chemical compositions and microstructures of the microspheres were investigated by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The electrical conductivity of the prepared SiO2/ PG-Fe3+/Ag core–shell microspheres was about 1000 S/cm. When the microspheres were filled in methyl vinyl silicone rubber (MVQ), the obtained composites showed good mechanical and electrical properties, indicating their potential applications as conductive and electromagnetic shielding materials. [ABSTRACT FROM AUTHOR]

In this study, the surface of ultra-high-molecular-weight-polyethylene (UHMWPE) fibers was modified by ozone pretreatment, followed by ultraviolet (UV) grafting, to enhance the interfacial properties of UHMWPE fibers/rubber composites. The fibers were first pretreated by ozone to introduce oxygen-functional groups. The graft polymerization of glycidyl methacrylate (GMA) onto the ozone-treated fibers was implemented by UV irradiation. The effects of time and GMA concentration on the grafting efficiency were investigated. The modified fibers were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). The XPS and FTIR results revealed that GMA was successfully grafted onto the fibers with epoxy groups. SEM images confirmed that a continuous layer of poly-(GMA) (PGMA) was grafted onto the fibers. The interfacial adhesion force of UHMWPE fibers with rubber matrix was characterized by H pullout testing, which showed that the maximum force the fibers/rubber composites increased by 79% over that of the untreated fibers. [ABSTRACT FROM PUBLISHER]

Surface modified fibrillar silicate (FS) was prepared by dopamine oxide polymerization and self-assembly of poly(dopamine) (PDA) on the FS surface, presynthesized silver nanoparticles subsequently adhered to the PDA functionalized FS (FS-PDA) surface by simply dipping FS-PDA in silver nanoparticles solution, owing to the metal-binding ability of catechol and nitrogen-containing groups on the PDA coating on the surface of FS. The chemical composition of the modified FS surface was determined by X-ray photoelectron spectroscopy. Surface morphological changes of the FS nanofibers were observed by transmission electron microscopy. The results indicated that the in situ spontaneous oxidative polymerization of dopamine on the FS surface and the immobilization of Ag nanoparticles on the surface of FS were successful. The FS-PDA/Ag demonstrated a significant enhancement in antibacterial properties compared to the pristine FS by using Escherichia coli as model strain. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39859. [ABSTRACT FROM AUTHOR]

A novel method for the preparation of electrical conductive surface silvered acrylonitrile-butadiene rubber (NBR) was developed. Dopamine was spontaneously oxide polymerized and deposited onto the surface of NBR. Electroless plating of silver was carried out on the poly(dopamine) (PDA)-functionalized NBR surface. The composition of the NBR surface was studied by X-ray photoelectron spectroscopy (XPS). XPS results showed that PDA was successfully deposited onto the NBR surface. The morphology of the NBR surface was observed by scanning electron microscopy (SEM). The SEM images showed that PDA had formed a distinctive layer ready for electroless deposition of silver. The catechol/quinone groups on the PDA molecular structure can be used as binding sites for silver ions. The silvered NBR showed high surface conductivity of 1.4 Ω. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: A facile method was developed to prepare silica–silver core–shell composite microspheres with continuous, compact, and conductive silver layers. The procedure involves dopamine oxidative self-polymerization and electroless plating. The poly(dopamine) layer was used as the chemi-sorption sites for silver ions and promoted the silver deposition. The electroless plating procedure involves a combination of surface activation, seeding growth, and deposition. The chemical composition and the crystal structure of the silica–silver core–shell composite microspheres were studied by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. In addition, the surface morphology and chemical composition of each composite microsphere were confirmed by scanning electron microscopy and energy dispersive X-ray spectroscopy. The results demonstrated that the silver layer on the silica surface was continuous and compacted. [Copyright &y& Elsevier]

A novel procedure was demonstrated for the preparation of carbon nanotubes (CNTs) decorated with silver nanoparticles through poly(dopamine) (PDA) surface functionalization and ultraviolet (UV) irradiation. The CNT surfaces were first functionalized by a bio-inspired PDA layer. X-ray photoelectron spectroscopy (XPS) results showed that PDA layer with thicknesses in nanometers were formed on the outer surfaces of the CNTs. With the immersion of the PDA-coated CNTs (CNTs-PDA) into a silver plating bath, the silver ions attached to the CNTs-PDA surfaces were reduced in situ to silver nanoparticles by using the N-containing groups and reducing ability of PDA. The dense silver nanoparticles were further decorated on the CNTs-PDA surfaces under UV irradiation. High-resolution transmission electron microscopy (HRTEM) images showed that the spherical silver nanoparticles were about 3–4 nm in diameter and uniformly distributed on the outer surfaces of the CNTs. The distance between the nanoparticles was less than 10 nm. The as-prepared silver-decorated CNTs-PDA nanocomposites had excellent electrical conductivity, with a surface conductivity of up to 340 S/cm. [ABSTRACT FROM AUTHOR]

To solve the poor interface between aramid fiber and rubber, this paper studies a method of constructing nanostructures on the fiber surface. First, functional groups such as hydroxyl and amino groups were introduced onto aramid fiber through the Michael addition of tannic acid and polyethyleneimine. Then, the modified aramid fiber was impregnated in the aramid nanofiber/carbon nanotube aqueous dispersion to prepare a surface-coated fiber. The fibers and surface nanostructures were characterized by scanning electron microscopy, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, thermalgravimetric analysis, and H pull-out tests in detail. The results show that the H pull-out force of the coated fiber is increased by 126.4% compared with the original aramid fiber, which is due to the good mechanical interlocking at the interface of the composites. In addition, carbon nanotubes could form a conductive path through mutual entanglement and overlap on the surface of aramid fiber, which also gives the function of real-time monitoring of deformation of the composites. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Immobilization of silver nanoparticles on the dopamine functionalized polyimide (PI) films was carried out by photo-induced silver ion-reduction under atmosphere conditions. The dopamine has been successfully deposited on the PI surface in mild aqueous environments. The effects of pH, dopamine concentration and reaction time on the dopamine polymerization were investigated. The water contact angles of the poly(dopamine) functionalized PI films reduced remarkably in comparison with that of the pristine PI film. The chemical composition and structure of the UV-induced deposited-silver on the modified PI films were characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The topography of the modified PI films was investigated by scanning electron microscope (SEM). The deposited poly(dopamine) layer acted as binding sites for the silver ions. The silver-plated PI films showed good antibacterial activity due to that biofilm formation was inhibited on the polymeric surfaces in contact with bacteria. [Copyright &y& Elsevier]