Resonant TE Transmission Through a Continuous Metal Film: Perspectives for Low-Loss Plasmonic Elements

Whereas resonant transverse magnetic transmission across an undulated continuous metal film is achieved with the mediation of plasmon modes excited by the undulation, it is shown here that transverse electric (TE) resonant transmission through a continuous metal film can also be achieved with the mediation of the second-order TE₁ mode of a dielectric slab waveguide having the metal film sandwiched at its middle. The demonstration is made by using the materials currently used in the domain of optical security and counterfeit deterrence: ZnS is shown to possibly be a lossless interface/adhesion layer between a polymer and a noble metal for plasmonic resonant elements.     

High Plasmonic Resonant Reflection and Transmission at Continuous Metal Films on Undulated Photosensitive Polymer

Whereas noble metal films deposited directly onto an undulated photosensitive polymer exhibit plasmon-mediated resonant transmission of free-space waves accompanied by excess losses of approximately 40 %, adequate hard baking of the photosensitive polymer, together with pre- and post-deposition of nanometer-thick ZnS or MgF₂ dielectric interfacial layers, restores excellent propagation conditions for the long-range plasmon mode, reducing resonant transmission excess losses to 10 %, and creating the conditions for the experimental evidence of the long-sought plasmonic anomalous reflection phenomenon.     

Synthesis and characterization of metal ion imprinted nano-porous polymer for the selective recognition of copper

Selective recognition of metal ions utilizing metal ion-imprinted polymers (MIIPs) received much importance in diverse fields owing to their high selectivity for the target metal ions. In the present study, a copper ion imprinted polymer was synthesized without an additional complexing ligand or complex with a broad aim to avoid the conventional extra metal ion complexing ligand during the synthesis of MIIP. The complete removal of the copper metal ion from the MIIP was confirmed by AAS and SEM–EDX. SEM image of the MIIP exhibited nano-patterns and it was also found to be entirely different from that of non-imprinted polymer and polymer with copper metal ions. BET surface area analysis revealed more surface area (47.96 m²/g) for the Cu(II)-MIIP than non-imprinted control polymer (41.43 m²/g). TGA result of polymer with copper metal ion indicated more char yield (18.41%) when compared to non-imprinted control polymer (8.3%) and Cu(II)-MIIP (less than 1%). FTIR study confirmed the complexation between Cu(II)-MIIP and Cu(II) metal ion through carbonyl oxygen of acryl amide. The Cu(II)-MIIP exhibited an imprinting efficiency of 2.0 and it was showing 8% interference from a mixture of Zn, Ni and Co ions. A potentiometric ion selective electrode devised with Cu(II)-MIIP showed more potential response for Cu(II) ion than that was fabricated from non-imprinted polymer.     

Optical Transmission Through Multilayered Ultra-Thin Metal Gratings

Optical transmission properties of multilayered ultra-thin metal gratings are numerically studied. The transmission spectrum has a broad stop-band with extremely low transmittance compared to that of a single-layer one for TM polarization. The stop-band is shown to be formed by multiple-interference tunneling and various plasmon resonance processes in ultra-thin-metal and dielectric multilayers. That is on the transmission background of non-apertured metal/dielectric multilayer structures that have low transmission in the long-wavelength range due to destructive multiple-interference tunneling, the transmission is further suppressed in the stop-band by plasmon resonances in the top metal/dielectric layers, e.g., the anti-symmetric bound surface plasmon mode in the ultra-thin metal layer and the gap surface plasmon mode in the metal-sandwiched dielectric layer. High transmission beyond the stop-band is due to coupled gap surface plasmon mode in the entire multilayer structures. Applications of the optical properties of the multilayered ultra-thin metal gratings are suggested for optical filtering (wavelength or polarization selective).     

Propagation Loss of Long-Range Surface Plasmon Polariton Gold Stripe Waveguides in the Thin-Film Limit

Propagation loss experienced by long-range plasmon polaritons in ultrathin gold stripe waveguides embedded in different polymer cladding materials was studied and correlated with atomic-scale characterization of the gold film structure. We identify the main sources of experimentally observed propagation loss which deviates from ideal values in the thin-film limit. Increased loss can be translated to an increased effective thickness of the ultrathin films due to incomplete surface coverage and the presence of diffuse interfaces, both of which depend significantly on the choice of cladding material. The results illustrate the importance of atomic-scale dynamics of metal film formation for the selection of optimum substrate materials for surface plasmon polariton waveguides, resonant transmission structures, and semitransparent electrical contacts.     

Simultaneously Enhancing the Thermal Stability,Mechanical Modulus,and Electrochemical Performance of Solid Polymer Electrolytes by Incorporating 2D Sheets

Solid state electrolytes are the key components for high energy density lithium ion batteries and especially for lithium metal batteries where lithium dendrite growth is an inevitable obstacle in liquid electrolytes. Solid polymer electrolytes based on a complex of polymers and lithium salts are intrinsically advantageous over inorganic electrolytes in terms of processability and film‐forming properties. But other properties such as ionic conductivity, thermal stability, mechanical modulus, and electrochemical stability need to be improved. Herein, for the first time, 2D additives using few‐layer vermiculite clay sheets as an example to comprehensively upgrade poly(ethylene oxide)‐based solid polymer electrolyte are introduced. With clay sheet additives, the polymer electrolyte exhibits improved thermal stability, mechanical modulus, ionic conductivity, and electrochemical stability along with reduced flammability and interface resistance. The composite polymer electrolyte can suppress the formation and growth of lithium dendrites in lithium metal batteries. It is anticipated that the clay sheets upgraded solid polymer electrolyte can be integrated to construct high performance solid state lithium ion and lithium metal batteries with higher energy and safety.     

Surface Plasmon Polariton Excitation in Metallic Layer Via Surface Relief Gratings in Photoactive Polymer Studied by the Finite-Difference Time-Domain Method

We performed numerical investigations of surface plasmon excitation and propagation in structures made of a photochromic polymer layer deposited over a metal surface using the finite-difference time-domain method. We investigated the process of light coupling into surface plasmon polariton excitation using surface relief gratings formed on the top of a polymer layer and compared it with the coupling via rectangular ridges grating made directly in the metal layer. We also performed preliminary studies on the influence of refractive index change of photochromic polymer on surface plasmon polariton propagation conditions.     

Microwave absorption by folded DNA chains

Absorption of radiation by DNA polymer is calculated for the case of bent polymer chains. The molecule is assumed to be straight except for localized bends. The region between two bends is studied in particular. The vibrational properties of the bends are parameterized by a transmission and a reflection coefficient. A general Green function expression for absorption is studied for various values of the damping rate, as well as the transmission/reflection coefficients. Curves of absorption vs frequency are shown for a number of cases.     

Mass balance of heavy metal uptake by encapsulated cultures ofKlebsiella aerogenes

Dialysis was employed as a method of speciating heavy metals in cultures of an extracellular polymer forming strain ofKlebsiella aerogenes. A noncapsulated strain of the same bacterium was used as a control, and a mass balance of copper, cadmium, cobalt, nickel, and manganese in batch culture at pH 4.5 and pH 6.8 and in continuous culture at pH 6.8 was constructed. Copper and cadmium were accumulated by the cell during rapid proliferation whereas all 5 metals were bound nonspecifically by extracellular polymer produced during stationary phase and at low dilution rates. The presence of extracellular polymer appeared to inhibit cellular uptake of nickel. At the lower pH, metal uptake was considerably reduced. The results are discussed in the context of metal removal in the activated sludge process of waste water treatment.     

Synthesis of a Nano-Silver Metal Ink for Use in Thick Conductive Film Fabrication Applied on a Semiconductor Package

The success of printing technology in the electronics industry primarily depends on the availability of metal printing ink. Various types of commercially available metal ink are widely used in different industries such as the solar cell, radio frequency identification (RFID) and light emitting diode (LED) industries, with limited usage in semiconductor packaging. The use of printed ink in semiconductor IC packaging is limited by several factors such as poor electrical performance and mechanical strength. Poor adhesion of the printed metal track to the epoxy molding compound is another critical factor that has caused a decline in interest in the application of printing technology to the semiconductor industry. In this study, two different groups of adhesion promoters, based on metal and polymer groups, were used to promote adhesion between the printed ink and the epoxy molding substrate. The experimental data show that silver ink with a metal oxide adhesion promoter adheres better than silver ink with a polymer adhesion promoter. This result can be explained by the hydroxyl bonding between the metal oxide promoter and the silane grouping agent on the epoxy substrate, which contributes a greater adhesion strength compared to the polymer adhesion promoter. Hypotheses of the physical and chemical functions of both adhesion promoters are described in detail.     

Synthesis of thermally stable carboxymethyl cellulose/metal biodegradable nanocomposites for potential biological applications

A green approach is described that generates bulk quantities of nanocomposites containing transition metals such as Cu, Ag, In, and Fe at room temperature using a biodegradable polymer, carboxymethyl cellulose (CMC), by reacting respective metal salts with the sodium salt of CMC in aqueous media. These nanocomposites exhibit broader decomposition temperatures when compared with control CMC, and Ag-based CMC nanocomposites exhibit a luminescent property at longer wavelengths. The noble metals such as Au, Pt, and Pd do not react at room temperature with aqueous solutions of CMC, but do so rapidly under microwave irradiation (MW) conditions at 100 degrees C. This environmentally benign approach, which provides facile entry to the production of multiple shaped noble nanostructures without using any toxic reducing agent such as sodium borohydride (NaBH4), hydroxylamine hydrochloride, and so forth, and/or a capping/surfactant agent, and which uses a benign biodegradable polymer CMC, could find widespread technological and medicinal applications. The ensuing nanocomposites derived at room temperature and MW conditions were characterized using scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, UV-visible spectroscopy, X-ray mapping, energy-dispersive analysis, and thermogravimetric analysis.     

Optical Transmission in Arrayed Asymmetric Multilayered Ultra-Thin Metal Stripes

An arrayed structure of asymmetric multilayered ultra-thin metal stripes is proposed to achieve a narrow transmission peak in an ultra-broad transmission valley, which is formed due to the destructive multiple-interference tunneling existed in an ultra-thin metal and dielectric multilayers. The transmission peak is influenced by two resonant modes. One is the coupled gap surface plasmon (cg-SP) resonance mode confined in entire multilayered ridges, the other is the modified gap surface plasmon (g-SP) mode within metal-dielectric layers. Furthermore, the transmission mode and the stopband are tunable in a wide range through designing the dimension parameters. The proposed plasmonic structure is promising for wideband filters.     

Modulation of tubulin-nucleotide interactions by metal ions: comparison of beryllium with magnesium and initial studies with other cations.

With microtubule-associated proteins (MAPs) BeSO4 and MgSO4 stimulated tubulin polymerization as compared to a reaction mixture without exogenously added metal ion, while beryllium fluoride had no effect (E. Hamel et al., 1991, Arch. Biochem. Biophys. 286, 57-69). Effects of both cations were most dramatic at GTP concentrations in the same molar range as the tubulin concentration. We have now compared effects of beryllium and magnesium on tubulin-nucleotide interactions in both unpolymerized tubulin and in polymer. Polymer formed with magnesium had properties similar to those of polymer formed without exogenous cation, except for a 20% lower stoichiometry of exogenous GTP incorporated into the latter. In both polymers the incorporated GTP was hydrolyzed to GDP. Stoichiometry of GTP incorporation into polymers formed with beryllium or magnesium was identical, but much of the GTP in the beryllium polymer was not hydrolyzed. The beryllium polymer was more stable than the magnesium polymer. Beryllium also differed from magnesium in only weakly enhancing the binding of GTP in the exchangeable site of unpolymerized tubulin, while neither cation affected GDP exchange at the site. If both cations were present in a reaction mixture, polymer stability was little changed from that of the beryllium polymer, but most of the GTP incorporated into polymer was hydrolyzed. Six additional metal salts (AlCl3, CdCl2, CoCl2, MnCl2, SnCl2, and ZnCl2) also stimulated MAP-dependent tubulin polymerization, but enhanced polymer stability did not correlate with polymer GTP content. We postulate that enhanced polymer stability is a consequence of cation binding directly to tubulin and/or polymer while deficient GTP hydrolysis in the presence of beryllium, as well as aluminum and tin, is a consequence of tight binding of cation to GTP in the exchangeable site.     

Affinity precipitation of alpha-amylase inhibitor from wheat meal by metal chelate affinity binding using cu(II)-loaded copolymers of 1-vinylimidazole with N-isopropylacrylamide

A method for purifying alpha-amylase inhibitor from wheat meal based on immobilized metal affinity with a thermosensitive copolymer is developed. The studies represent the thermoprecipitation properties of the copolymers of N-isopropylacrylamide (NIPAM) with iminodiacetic acid (IDA) and 1-vinylimidazole (VI), respectively. The polymer which is obtained by the copolymerization of 1-vinylimidazole and N-isopropylacrylamide, charged with Cu(II), exhibited specific interaction of the metal ions to the protein inhibitor. The precipitation was induced by salt and the recovery of the amylase inhibitor was achieved by dissolving the inhibitor-polymer complex in imidazole buffer and subsequent precipitation of the polymer. A single family of the alpha-amylase inhibitor was recovered from the polymer with 89% yield and about fourfold purification. The SDS-PAGE pattern showed significant purification of the inhibitor. The binding of the inhibitor to the Cu(II)-polymer conjugate depends upon the Cu(II) concentration in the copolymer and also upon the concentration of the protein. The recovered polymer could be reused with reasonable efficiency. Copyright 1998 John Wiley & Sons, Inc.     

Polymer–cobalt(III) complexes: structural analysis of metal chelates on DNA interaction and comparative cytotoxic activity

A new series of pendant-type polymer-cobalt(III) complexes, [Co(LL)₂(BPEI)Cl]²⁺, (where BPEI?=?branched polyethyleneimine, LL?=?dipyrido[3,2-a:2′,3′-c](6,7,8,9-tetrahydro)phenazine (dpqc), dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq) and imidazo[4,5-f]1,10-phenanthroline (ip)) each with three different degrees of coordination have been synthesized and characterized. Studies to know the mode and strength of interaction between these polymer–metal complexes and calf thymus DNA have been performed by UV–Visible absorption and emission techniques. Among these series, each polymer metal complex having higher binding strength with DNA has been selected to test against human cancer/normal cell lines. On the basis of these spectral studies, it is proposed that our polymer–metal complexes bind with DNA mainly through intercalation along with some electrostatic binding. The order of binding strength for the complexes with ligand, dpqc?>?dpq?>?ip. The analysis of the results suggests that polymer–cobalt(III) complexes with higher degree of coordination effectively binds with DNA due to the presence of large number of positively charged cobalt(III) chelates in the polymer chain which cooperatively act to increase the overall binding strength. These polymer–cobalt(III) complexes with hydrophobic ligands around the cobalt(III) metal centre favour the base stacking interactions via intercalation. All the complexes show very good anticancer activities and increasing of binding strength results in higher inhibition value. The polymer–cobalt(III) complex with dpqc ligand possess two fold increased anticancer activity when compared to complexes with other ligands against MCF-7 cells. Besides, the complexes were insensitive towards the growth of normal cells (HEK-293) at the IC₅₀ concentration.     

壳聚糖-g-N.羧甲基-二(2-苯并眯唑)-1,2-乙二醇的制备及其性能

以2-溴乙酸、壳聚糖、二（2-苯并咪唑）-1,2-乙二醇为原料,利用接枝作用将化学修饰后的小分子药物二（2-苯并咪唑）-1,2-乙二醇连接在天然高分子壳聚糖（CTS）上。并以。HNMR,IR,热分析及XRD等方法对其结构进行表征并研究接枝聚合物的理化性质。本文采用络合滴定法测定了接枝聚合物对一系列重金属离子的吸附作用;采用震荡法进行悬菌定量杀菌实验;还以经典的静态失重法研究了合成的聚合物在腐蚀介质中对N80钢片腐蚀的抑制作用。结果表明：小分子药物-（2-苯并咪唑）-1,2-乙二醇在接枝到天然高分子壳聚糖后热稳定性提高,在酸中具有良好的溶解度,对金属离子吸附能力在一个较宽温度范围内得以保持;同时增强了抑菌力,降低了最小抑菌浓度;利用BBIE与CTS韵协同作用提高了聚合物对金属腐蚀的抑制能力。     

A Mössbauer study of the interaction of chitosan and D-glucosamine with iron and its relevance to other metalloenzymes

The interaction of iron with water-soluble polymer chitosan and monomer d-glucosamine is investigated by M?ssbauer spectroscopy. The 4.2 K M?ssbauer spectrum of Fe-water-soluble chitosan complex indicates the presence of a magnetic pattern and a quadrupole doublet, and analysis of the spectral data leads to the conclusion that an Fe(II) state is partially stabilized in this system. Fe-glucosamine (monomer of chitosan) complex, on the other hand, clearly stabilizes the Fe(II) state in the acidic pH range as evidenced from the isomer shift extracted from the M?ssbauer spectra. The oxidation state of the metal ion in the complex is found to be pH dependent. Indirect evidence supporting the involvement of amino group in the bonding with the metal ion is discussed. From the analysis of the experimental data under varying experimental conditions, it is concluded that the metal ion in the complex is at least tetracoordinated and at most hexacoordinated with O/N ligands of the polymer or monomer and thus corroborates the bonding scheme proposed earlier.     

Metal complexation of chitosan and its glutaraldehyde cross-linked derivative

The physicochemical characterization of metal complexed with chitosan (CS) and its glutaraldehyde cross-linked derivative (CSGA) was investigated. Seven metal ions from chromium through zinc of the first row of the transition metals were selected for complexation. Structural features pertinent to where and how metals bind into both polymers are our main interest. Studies using solid-state NMR spectroscopy and XRPD (X-ray powder diffraction) supported by ESR spectroscopy, ICP-OES (inductively couple plasma-optical emission spectroscopy) and far-FTIR spectroscopy for metal interaction with nitrogen sites at C-2 of the metal-polymer complexes were performed. Theoretical calculations of the metal-polymer ratio, the approximate charges on nitrogen for both amine and imino-linker, and the proton affinity between an alcohol group from the polymer and an amino/imino group are reported. A helical coiled chitosan model and a 2C1L (two-chitosans with one linker) model are proposed here. The metal uptake mechanism for both polymers is concluded to be absorption within the polymers, rather than adsorption on the polymer surface.     

A mixed-valence Cu(I)-Cu(II) and metal-metal bond containing coordination polymer obtained from an in situ oxidation reaction route

A new mixed-valence copper coordination polymer with copper-copper metal bonds in a two-dimensional network was generated from an in situ oxidation reaction route under hydrothermal conditions. The synthesis of this coordination polymer demonstrated that the novel compounds that may not be accessible using the known methods could be synthesized via an oxidation reaction route. The reaction conditions are mild enough to keep the building blocks intact during the oxidation and self-assembly process under hydrothermal conditions.