In‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to miniemulsion polymerization

We present in‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to prepare hybrid latex particles by miniemulsion polymerization. On the surface of a silver nanoparticle/silica nanoparticle/acrylic polymer hybrid layer formed in‐situ on a polyethylene terephthalate (PET) substrate, a copper film is deposited using electroless copper deposition. Silver nanoparticles, which are formed in‐situ via the reduction of silver ion by radical species and subsequent annealing, work as a catalyst for the electroless deposition. Miniemulsion polymerization via the in‐situ formation of nanoparticles affords nanoparticle/acrylic polymer hybrid latex particles and polymer particles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42675.     

Spectroscopic analysis and catalytic application of biopolymer capped silver nanoparticle,an effective antimicrobial agent

Microbial reduction of silver ion (conc. 1 mM AgNO₃) was performed by Alkaliphilus oremlandii strain ohILAs in an alkaline pH 10. The synthesized silver nanoparticle was stabilized by poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) biopolymer which was also synthesized by the microbial culture of Alkaliphilus oremlandii strain ohILAs at pH8. The particle size and shape of the silver nanoparticles was studied by dynamic light scattering and under a transmission electron microscope and it was found that the particle size of polymer stabilized colloidal silver was comparatively lower (22–43nm) than that for the unstabilized one (63–93 nm). The stabilization of nanoparticles in polymer dispersed medium after around 60 days was confirmed from analysis of UV‐visible spectroscopy and scanning electron microscopy. The crystalline peaks as recorded with X‐ray's diffraction were observed at 2θ values of 38° and 43°, indicating the fcc crystalline structure of the silver nanoparticle. The antimicrobial activity of silver nanoparticles on gram‐negative bacteria strain (Escherichia coli XL1B) and gram‐positive strain (Lysinibacillus fusiformis) showed better performance by the solution of polymer stabilized nanoparticle than that for the non polymer stabilized one. The reduction of nitro group in p‐nitrophenol to p‐aminophenol was observed from the analysis of UV‐Visible spectroscopy in which, the shifting of absorption peak at 400 to 295 nm and the simultaneous regeneration of light brown color (λ_max 410 nm) of silver nanoparticles confirmed the catalytic activity of silver nanomaterials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41495.     

Fabrication of polycrystalline silver nanowires via reversed micelle with amphiphilic diblock copolymer and aluminum oxide template at controlled temperature

An amphiphilic diblock copolymer consisting of methyl methacrylate and methacrylic acid was synthesized using atom transfer radical polymerization via a hydrolysis process design. Silver nanoparticles were synthesized by a reverse micelle method using the synthesized diblock copolymer as a surfactant. Silver nanoparticle‐embedded fibers were then fabricated using an anodic aluminum oxide template. Silver nanoparticle‐embedded porous polymer fibers were fabricated by adding unreactive diphenyl sulfide in polymer matrix. They are expected to be applied to recyclable metal catalyst systems. After sintering of silver nanoparticle‐embedded polymer fibers at a relatively lower temperature, silver nanowires were fabricated. Moreover, the surfactant effect on both self assembly of nanoparticle clusters and silver nanowires surface smoothness were compared with the previously reported results. Silver nanoparticles coordinated amphiphilic copolymer was found to reveal higher thermal resistance. POLYM. COMPOS., 31:1352–1359, 2010. © 2009 Society of Plastics Engineers     

Nanosilver Colloids-Filled Photonic Crystal Arrays for Photoluminescence Enhancement

For the improved surface plasmon-coupled photoluminescence emission, a more accessible fabrication method of a controlled nanosilver pattern array was developed by effectively filling the predefined hole array with nanosilver colloid in a UV-curable resin via direct nanoimprinting. When applied to a glass substrate for light emittance with an oxide spacer layer on top of the nanosilver pattern, hybrid emission enhancements were produced from both the localized surface plasmon resonance-coupled emission enhancement and the guided light extraction from the photonic crystal array. When CdSe/ZnS nanocrystal quantum dots were deposited as an active emitter, a total photoluminescence intensity improvement of 84% was observed. This was attributed to contributions from both the silver nanoparticle filling and the nanoimprinted photonic crystal array.     

Semitransparent poly(styrene‐r‐maleic anhydride)/alumina nanocomposites for optical applications

This article presents the development and characterization of transparent poly(styrene‐r‐maleic anhydride) (SMA)/alumina nanocomposites for potential use in optical applications. Chemically treated spherical alumina nanoparticles were dispersed in an SMA matrix polymer via the solution and melt‐compounding methods to produce 2 wt % nanocomposites. Field emission scanning electron microscopy was used to examine the nanoparticle dispersion. When the solution method was used, nanoparticle reagglomeration occurred, despite the fairly good polymer wetting. However, through the coating of the alumina nanoparticles with a thin layer (ca. 20 nm) of low‐molecular‐weight SMA, reagglomeration was absent in the melt‐compounded samples, and this resulted in excellent nanoparticle dispersion. The resultant nanocomposites were semitransparent to visible light at a 2‐mm thickness with improved UV‐barrier properties. Their impact strengths, tensile strengths, and strains at break were slightly reduced compared with those of their neat resin counterpart, whereas a small enhancement in their moduli was achieved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Surface grafting of carbon fibers with artificial silver‐nanoparticle‐decorated graphene oxide for high‐speed electrical actuation of shape‐memory polymers

Poor heat conduction in the interface between the carbon fiber and polymer matrix is a problem in the actuation of shape‐memory polymer (SMP) composites by Joule heating. In this study, we investigated the effectiveness of grafting silver‐nanoparticle‐decorated graphene oxide (GO) onto carbon fibers to improve the electrothermal properties and Joule‐heating‐activated shape recovery of SMP composites. Self‐assembled GO was grafted onto carbon fibers to enhance the bonding of the carbon fibers with the polymeric matrix via van der Waal's forces and covalent crosslinking, respectively. Silver nanoparticles were further self‐assembled and deposited to decorate the GO assembly, which was used to decrease the thermal dissimilarity and facilitate heat transfer from the carbon fiber to the polymer matrix. The carbon fiber was incorporated with SMP to achieve the shape recovery induced by Joule heating. We found that the silver‐nanoparticle‐decorated GO helped us achieve a more uniform temperature distribution in the SMP composites compared to those without decoration. Furthermore, the shape‐recovery behavior and temperature profile during the Joule heating of the SMP composites were characterized and compared. A unique synergistic effect of the carbon fibers and silver‐nanoparticle‐decorated GO was achieved to enhance the heat transfer and a higher speed of actuation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41673.     

New approach to antibacterial treatment of cotton fabric with silver nanoparticle–doped silica using sol–gel process

In this study, cotton fabric was successfully modified to have an antibacterial property through use of the sol–gel process. Dodecanethiol‐capped silver nanoparticles, which have powerful antibacterial activity, were incorporated in silica sol. The starting materials were silver nitrate, tetraoctylammonium bromide, sodium borohydride, chloroform, 1‐dodecanethiol, ethanol, tetraethylorthosilicate, and water. The cotton fabric was padded with dodecanethiol‐capped silver nanoparticle–doped sol, dried at 60°C, and cured at 150°C. Scanning electron microscopy showed a uniform and continuous layer of doped sol on the fiber surface. The antibacterial effects of the treated cotton fabric against Escherichia coli were examined and found to be excellent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101:2938–2943, 2006     

Aptitude of Graphene Oxide–Silver in Advance Polymer Nanocomposite: A Review

This is a state-of-the art overview on polymer/graphene oxide–silver nanoparticle nanocomposite. Different polymer/graphene oxide–silver nanoparticle categories have been elucidated using polyethersulfone, polyimides, polyindole, poly(vinylidene fluoride), polyaniline, polyvinyl pyrrolidone, and poly(3,4-ethylenedioxythiophene). In situ reduction of silver salt and particle decoration on graphene oxide surface were effective to develop interaction between nanoparticles. Essential features of polymer/graphene oxide–silver nanoparticle revealed several advance technical applications. Conducting polymer/graphene oxide–silver nanoparticle is promising material for sensor, supercapacitor, and electrodes. Polymer/graphene oxide–silver nanoparticle possesses relevance in cancer treatment, gene transfection, cellular probing, imaging, antibacterial action, etc. Polyimide/graphene oxide–silver nanoparticle can also effectively prevent membrane bifouling. Catalytic activity of composites was also detected toward oxygen reduction in energy devices.     

Silver nanoparticle deposition on hydrophilic multilayer film surface and its effect on antimicrobial activity

Silver nanoparticles were deposited on the surface of the external polyamide 6 (PA6) layer of a multilayer film, by spraying and ultrasound‐assisted methods. The effect of silver nanoparticles content and deposition method on the mechanical and optical properties of the multilayered films as well as the efficiency of silver ion release and their fungicidal characteristics were evaluated. Itaconic (IA) and Maleic anhydride (MA) were used as adhesion promoter agents for preventing the agglomeration of the silver nanoparticles and for improving the adhesion to the PA6 polymer surface. With IA, a homogeneous distribution of silver nanoparticles on the PA6 surface was achieved. The silver ion release and biocide effect of the multilayered films was found to be dependent on the anhydride type and on the deposition method used. The multilayer films with a layer of PA6‐silver nanocomposite demonstrated good fungicidal activity, specifically against fungus Aspergillius niger. The observed results could be applied in the design of industrial films for packaging. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mechanical and antimicrobial properties of multilayer films with a polyethylene/silver nanocomposite layer

A layer of a polyethylene–silver nanoparticles composite was deposited on a five layer barrier film structure. Different methods were used for the nanocomposite layer deposition: laminating, casting, and spraying over the multilayer structure. For the casting and spraying methods, the silver nanoparticles were previously dispersed in the polymer solution, with the assistance of ultrasound energy. The effect of silver nanoparticles and deposition method on the barrier, mechanical, and optical properties of the multilayer films was evaluated. The efficiency of silver ion release from the PE‐Silver nanocomposite deposited on the multilayer films and their antimicrobial characteristics were investigated and discussed. The silver ion release and biocide effect of the multilayer films was found to be dependant on the silver nanoparticle content and on the deposition method used. The observed results could be helpful in the design of industrial films for packaging. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Carboxylation of Terminal Alkynes with Carbon Dioxide Catalyzed by Poly(N‐Heterocyclic Carbene)‐Supported Silver Nanoparticles

An N‐heterocyclic carbene (NHC) polymer supported silver nanoparticle catalyst system was developed. The novel nano‐composite catalyst demonstrated very high activity and excellent stability and reusability in the carboxylation of terminal alkynes with carbon dioxide at ambient conditions. The unique N‐heterocyclic carbene polymer and silver nanoparticle composite structure provided a synergistic effect on activation of terminal alkynes and carbon dioxide that contributed to the high catalytic activity. The poly‐NHC‐silver catalyst exhibited excellent substrate generality and tolerance to various functionalities. In addition, the catalyst is stable to air and moisture and can be easily recovered and reused.     

Preparation of doubly responsive polymer functionalized silica hybrid nanoparticles via a one‐pot thiol‐isocyanate click reaction at room temperature

Well‐defined poly(N‐isopropylacrylamide) and poly(2‐(diethylamino) ethyl methacrylate) were synthesized first by a reversible addition‐fragmentation chain transfer process. These polymers were then reduced to generate an end thiol group to react with isocyanate groups on the surface of silica nanoparticles, which were pretreated with toluene‐2,4‐diisocyanate, by a one‐pot “click” reaction to prepare temperature and pH responsive polymer functionalized hybrid silica nanoparticles. The polymer functionalized silica hybrid nanoparticles were characterized by a range of techniques such as Fourier transform infrared spectroscopy and dynamic light scattering. The doubly responsive polymer functionalized silica hybrid nanoparticles show both temperature and pH responsive behavior and their solution properties were dependent on the ratio of the two polymers on the surface of silica. Covalent functionalization of the silica nanoparticle with well‐defined temperature and pH responsive polymers was accomplished via a one‐pot thiol‐isocyanate click reaction. This reaction was found to be extremely efficient in producing doubly responsive polymer functionalized silica hybrid nanoparticle, even at relatively low reaction temperature and short reaction time. Thermogravimetric analysis indicated that the same ratio of poly(N‐isopropylacrylamide) and poly(2‐(diethylamino)ethyl methacrylate) functionalized silica hybrid nanoparticle consisted of 42.46 wt% polymer. POLYM. COMPOS., 38:1454–1461, 2017. © 2015 Society of Plastics Engineers     

End-grafted polysilane--an approach to single polymer science

This Account describes our approach to single polymer science in which we use end-grafted polysilane. Single polymer science, by our definition, involves isolating and observing a single polymer chain and extracting its physical properties at the single molecule level. For this purpose, we developed the end-graft technique, which is a method for fixing a polymer terminus on a solid surface by forming a chemical bond between them. We applied this technique to polysilane, a semiconducting polymer with a one-dimensional silicon-catenated backbone. Our recent experimental achievements are reviewed, which include direct observations of polysilane single-molecular structures by atomic force microscopy, the formation of unique supramolecular structures, and the observation of temperature- and solvent-dependent UV absorption spectra that are characteristic of isolated polysilane chains end-grafted on a solid surface.     

Nanocomposites of silver nanoparticle and dinonylnaphthalene disulfonic acid‐doped thermoreversible polyaniline gel

Silver/polyaniline‐dinonylnaphthalene disulfonic acid (PANI‐DNNDSA) gel nanocomposites are prepared from the reduction of silver salt by polyaniline in formic acid medium. Scanning electron micrographs (SEM) indicate the presence of three‐dimensional fibrillar network structure and the silver nanoparticles remain dispersed within the PANI‐DNNDSA fibrillar network. Differential scanning calorimetric (DSC) study shows reversible first‐order phase transition characterizing the composite to behave as a thermoreversible gel. Transmission electron micrographs (TEM) show a decrease of nanoparticle size with increasing AgNO₃ concentration. Wide angle X‐ray scattering (WAXS) patterns show lamellar structure in the gel as well as in the gel metal nanocomposites (GMNCs) and the two melting peaks in the DSC patterns correspond to the melting of monolayer and bilayer crystals produced from the interdigitation of DNNDSA tails anchored from PANI chains within the PANI lamella. The above melting points are greater in the GMNCs than that of pure gel indicating the formation of complex melting thermogram with crystallites produced from the anchored surfactants tails at the surface of Ag nanoparticles. The GMNCs show a higher thermal stability than that of pure PANI‐DNNDSA gel. PANI‐DNNDSA gel has an emission peak at 354 nm but fluorescence quenching occurs in the GMNCs and the emission peak becomes red shifted. Also in the UV–vis spectra the π band‐polaron band transition peak shows a red shift and the DC conductivity increases with increasing Ag nanoparticle concentration in the GMNCs. The current (I)–voltage (V) characteristic curves indicate Ohmic nature of conductivity of the gel and the current at the same voltage increases appreciably with increasing Ag nanoparticle concentration. These GMNCs are easily processible due to its thermoreversible nature. So, an easily processible, thermally stable and highly conducting DNNDSA‐doped PANI‐Ag gel nanocomposite with interesting photoluminescent property has been successfully developed suitable for optoelectronic applications. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Synthesis and optical and thermal properties of poly[methyl(2,9‐diphenyl‐ 7,8‐benzophenanthryl)silylene‐co‐1,4‐bis(methylphenylsilyl)phenylene]

Poly[methyl(2,9‐diphenyl‐7,8‐benzophenanthryl)silylene‐co‐1,4‐bis(methylphenylsilyl)phenylene] (PMBS‐co‐BSP) was synthesized by the condensation reaction of dichloromethyl(2,9‐diphenyl‐7,8‐benzophenanthryl)silane and 1,4‐bis(chloromethylphenylsilyl)benzene with sodium in toluene. Optical and thermal behavior of the polymer was investigated. Because of the introduction of substituted benzophenanthryl groups into the Si atoms of the polymer, the UV absorption wavelength of the PMBS‐co‐BSP red‐shifted significantly in the UV region, and a strong photoluminescence band was observed in the visible region other than the near‐UV photoluminescence typical of normal polysilane. The photochemical behavior was examined both in solution and in thin film by fluorescence and UV spectroscopy. Irradiation of the PMBS‐co‐BSP with a low‐pressure mercury lamp in solution resulted in homolytic scission of silicone–silicone bonds; the fluorescence emission intensities decreased gradually with increasing UV irradiation time and the maximum emission wavelength blue‐shifted significantly. Irradiation of thin solid films of the PMBS‐co‐BSP in air led to the formation of photoproducts containing Si? OH and Si? O? Si groups. The PMBS‐co‐BSP began to weigh less at about 300 °C and the weight loss of the polymer at 700 °C was calculated to be 75% of the initial weight in N₂. Copyright © 2006 Society of Chemical Industry     

Emission properties of composite semiconducting polymer nanoparticles

A series of composite polymer nanoparticles was prepared from poly(N‐vinylcarbazole) (PVK) and poly(2,5‐bistriethoxy‐p‐phenylene vinylene‐alt‐phenylene vinylene) (BTEO–PPV‐alt‐PPV). The nanoparticle sizes were measured to be in the range of 50–80 nm with transmission electron microscopy. The photoluminescence intensity of PVK decreased with the content of BTEO–PPV‐alt‐PPV increasing in the composite polymer nanoparticles because the excited states in PVK were quenched by BTEO–PPV‐alt‐PPV. The emission from BTEO–PPV‐alt‐PPV was enhanced in the composite polymer nanoparticles because of energy transfer from PVK to BTEO–PPV‐alt‐PPV for excitation at the absorption maximum of PVK. The energy‐transfer efficiency was markedly improved in the composite polymer nanoparticles versus the composite polymer films according to emission spectral analyses. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Gelatin‐g‐poly(methyl methacrylate)/silver nanoparticle hybrid films and the evaluation of their antibacterial activity

We designed and prepared novel hybrid films of nanoparticles consisting of gelatin‐g‐poly(methyl methacrylate) (PMMA)/silver (Ag) polymers with ordered nanoporous, higher antibacterial activities. First, the gelatin‐grafted PMMA microspheres were fabricated with the in situ copolymerization of gelatin and alkenes under radical initiation, which acted as a stabilizer and regulator for Ag nanoparticle growth. Then, silver nitrate was entrapped in a copolymerization system at 40°C for 30 min. Finally, the gelatin‐g‐PMMA/Ag polymer hybrid films were prepared by the reduction of Ag⁺ with hydrazine, followed by emulsion solidification. The antibacterial activities of the gelatin‐g‐PMMA/Ag polymer hybrid films against Escherichia coli and Staphylococcus aureus were found with the disc diffusion method and colony count assays to be clear and lasting. In this study, our work not only presented a good example of a nanoporous antibacterial film material but also provided a facile method for making use of gelatin and metal/inorganic self‐assemble properties in graft copolymerization to prepare functional polymer hybrids, such as antibacterial, antithrombogenic, and dot‐quantum effect materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and light‐emitting properties of new poly(p‐phenylenevinylene) derivatives containing oxadiazole moiety

Two new poly(p‐phenylenevinylene) (PPV) derivatives containing oxadiazole moiety (OXA‐PPV1 and OXA‐PPV2) were synthesized by the Wittig condensation polymerization reaction. Their thermal and light‐emitting properties were investigated. The single‐ and triple‐layer electroluminescent (EL) devices with configurations of ITO/polymer/Al and ITO/polymer/OXD‐7/Alq₃/Al were fabricated. They exhibited blue emission at 470 nm for OXA‐PPV1 and green emission at 560 nm for OXA‐PPV2. The turn‐on voltages of triple‐layer device were 11 V for OXA‐PPV1 and 8 V for OXA‐PPV2. The triple‐layer EL devices showed much better performance than did the single‐layer devices. The spectra indicated energy transfer occurred from segments of side chain to polymer backbone. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 422–428, 2002     

Breathing‐in/breathing‐out approach to preparing nanosilver‐loaded hydrogels: Highly efficient antibacterial nanocomposites

The key objective of developing novel materials for hygienic living conditions is to lower the risk of transmitting diseases and biofouling. To this end, a number of silver–hydrogel nanocomposite systems are under development. In this study, we attempted a unique strategy to prepare silver‐nanoparticle‐loaded poly(acrylamide‐co‐N‐vinyl‐2‐pyrolidone) hydrogel composites. To load nanosilver particles into such a nonionic hydrogel, a novel breathing‐in/breathing‐out (BI–BO) approach was employed. As the number of BI–BO cycles increased, the amount of the silver nanoparticles loaded into these hydrogels also increased. This behavior was obvious and was confirmed by ultraviolet–visible spectroscopy and thermal analysis. Furthermore, the hydrogel–silver‐nanoparticle composites were confirmed with Fourier transform infrared spectroscopy and transmission electron microscopy studies. Antibacterial studies of these hydrogel–silver nanocomposites showed excellent results against Escherichia coli. The antibacterial activity increased with the number of BI–BO cycles, and samples that underwent three BI–BO cycles showed optimal bactericidal activity. The degree of crosslinking and the silver content had a great influence on the antibacterial efficacy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Silver–polyimide nanocomposite membranes: Macromolecular‐matrix‐mediated metallization of an aromatic,fluorinated polyimide yielding highly reflective films at low metal concentrations

Highly reflective, surface‐metalized, flexible polyimide films were prepared by the incorporation of a soluble silver‐ion complex, (hexafluoroacetylacetonato)silver(I) (AgHFA), into dimethylacetamide solutions of poly(amic acid) prepared from 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane. The thermal curing of solution‐cast silver(I)–poly(amic acid) films to 300°C led to cycloimidization of the amic acid with concomitant silver(I) reduction and the formation of a reflective, air‐side‐silvered surface at very low (2 wt % and 0.3 vol %) silver concentrations. The reflective surface evolved only when the cure temperature reached about 275°C, although X‐ray diffraction showed metallic silver in the hybrid film by 200°C. After a maximum specular reflectivity greater than 80% was achieved for the 2 wt % silver film, the specular reflectivity diminished sharply with further heating at a constant temperature of 300°C. Incorporating the AgHFA complex into the soluble, fully imidized form of poly{(1,3‐dihydro‐1,3‐dioxo‐2H‐isoindole‐2,5‐diyl)[2,2,2‐trifluoro‐1‐(trifluoromethyl)ethylidene](1,3‐dihydro‐1,3‐dioxo‐2H‐isoindole‐5,2‐diyl)‐1,4‐phenyleneoxy‐1,4‐phenylene[2,2,2‐trifluoro‐1‐(trifluoromethyl)ethylidene]‐1,4‐phenyleneoxy‐1,4‐phenylene} gave films that were 25% less reflective than those beginning with poly(amic acid). Though highly reflective, the films were not electrically conductive. The metalized membranes were thermally stable and maintained mechanical properties similar to those of the parent polyimide. Transmission electron microscopy revealed an air‐side, near‐surface layer of silver that was about 40 nm thick; the interior of the film had well‐dispersed metal particles with diameters mostly less than 2 nm. The near‐surface silver layer maintained its integrity because of physical entrapment of the metal nanoparticles beneath a thin layer of polyimide; that is, the practical adhesion of the metal layer was good. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2409–2418, 2007