A novel materials design procedure based on the co-doping of metal nanoparticle and azo dye compound （MNPADC） is developed to improve the properties of functional molecules. The synthesized materials were characteri...A novel materials design procedure based on the co-doping of metal nanoparticle and azo dye compound （MNPADC） is developed to improve the properties of functional molecules. The synthesized materials were characterized by transmission electron micrograph （TEM）, ultraviolet-visible absorption spectra （UV-Vis） and fluorescence spectra （FS）. It was found that the fluorescence intensity of methyl orange （MO） was enhanced by 5 times in the aqueous composite system doped with silver nanoparticles whereas it was reduced by 15% and 20% in composite films with co-mixing and coating structures, respectively. The results indicate that the properties of functional molecules can be greatly improved in composite film with supra molecular structure and that the procedure presented here is effective.展开更多
In recent years, immense interest has been paid to the biomolecular architecture with the aim of protein assembly in two di- mensions on solid substrates, and the constructions of clay-protein ultrathin films （CPUFs...In recent years, immense interest has been paid to the biomolecular architecture with the aim of protein assembly in two di- mensions on solid substrates, and the constructions of clay-protein ultrathin films （CPUFs） are particularly concerned. This paper gives an overview of the recent research concerning the protein molecules （lysozyme, papain, protamine, bovine serum albumin） immobilized on clay mineral （Na-saponite） platelets and assembled in monolayered or multilayered hybrid ultrafilms or nanofilms. Two techniques including alternate layer-by-layer （LbL） assembly and the Langmuir-Blodgett （LB） are de- scribed in detail. A variety of means, including UV-vis absorption, attenuated total reflectance Fourier transform infrared （ATR-FTIR） spectroscopy, XRD, AFM and surface chemistry techniques, have been described for characterization of the films in terms of quantification of protein and clay. The result reveals that electrostatic interaction is a prominent but not the only driving force in CPUF construction. In the case of LB technique, we managed to manipulate the elementary clay mineral platelets （1.3 nm in thickness） and assemble proteins into CPUFs with the aid of surfactants, and the formation of CPUFs was monitored via surface pressure vs. time （a--t） kinetics curves and surface pressure vs. area （a--A） isotherms. The factors that in- fluence protein adsorption on the clay layer, such as surfactants, the concentration of clay, equilibrium time, categories of pro- tein, and injection methods, were investigated. The parameters such as protein amount （nS）, packing density （O）, and average surface area per molecule （.（2） of deposited CPUFs were measured via method of surface chemistry and spectroscopy. By comparing the results of surface chemistry with those of adsorption experiments, we demonstrate that the surface chemistry method is a useful tool in investigating CPUFs. We also found that the water soluble protein molecules could form protein-clay hybrid monolayer over the dilute clay dispersions without addition of surfactants, and CPUFs containing elementary clay sheets and protein with great homogeneity were easily prepared by controlling certain surface pressure. To investigate the bio-catalytic performance of the immobilized lysozyme in CPUFs, we deposited CPUFs onto a cover glass, and installed the cover glass in a flow cell-grown reactor for Comamonas testosteroni （WDL7-GFP） incubation. The results show that the pro- liferation of WDL7-GFP is greatly suppressed by lysozyme, which demonstrates that lysozyme still retains its bioactivity after it is immobilized in the CPUFs.展开更多
Many technological applications require templates with nanoscale patterns.Block copolymer self-assembly is a method of choice for obtaining a large variety of such patterns,with greatest flexibility achieved when comb...Many technological applications require templates with nanoscale patterns.Block copolymer self-assembly is a method of choice for obtaining a large variety of such patterns,with greatest flexibility achieved when combined with a supramolecular approach.One of the ways to fabricate block copolymer templates is the Langmuir-Blodgett (LB) technique.Here,we briefly summarize recent work with LB films of polystyrene-poly(4-vinyl pyridine) (PS-P4VP) mixed with 3-n-pentade cylphenol (PDP),illustrating the different types of patterns possible and the principles governing them.One interesting pattern that can be easily achieved with this system is the so-called "nanostrand network",which,when used as a template for gold deposition,can produce double striped lines of gold.Here,we show how this pattern can be modified by acetone swelling to give rise to gold monolayer ribbons with internal structure.The results also suggest new insights into the early stages of morphology formation at the air/water interface.展开更多
Enabling the use of rationally designed thin films in technological devices is a recognized goal in materials science. However, constructing such thin films using highly ordered supramolecular architectures with well-...Enabling the use of rationally designed thin films in technological devices is a recognized goal in materials science. However, constructing such thin films using highly ordered supramolecular architectures with well-controlled size and growth direction has remained an elusive target. Here, we introduce a layer-by- layer protocol to grow hybrid thin films of molecule-based magnetic conductors comprising arachidic acid and donor bis（ethylenedioxy）tetrathiafulvalene （BEDO-TTF） as the organic component and Cu/Gd complexes as the inorganic component. The construction of layered hybrid thin films was achieved at ambient conditions by employing the Langmuir-Blodgett method, which provides good control over film thickness and packing of molecules in the monolayer. As demonstrated by X-ray diffraction, these films are crystalline with distinct organic and inorganic sublattices, where the BEDO-TTF molecular layer is interfaced with the inorganic layer. Due to the flexibility of the Langmuir-Blodgett deposition technique, this result indicates a route toward the preparation of well-ordered films with various functionalities, determined by the choice of the inorganic compound that is combined with the π-unit of BEDO-TFF. Moreover, the ability to deposit films on a variety of substrates establishes the potential for lower-cost device fabrication on inexpensive substrates.展开更多
Rotational motion of fluorophores chemically attached to polystyrene chain-ends in ultra-thin films on solid substrates was studied by single-molecule fluorescence de-focus microscopy.The collective feature of the rot...Rotational motion of fluorophores chemically attached to polystyrene chain-ends in ultra-thin films on solid substrates was studied by single-molecule fluorescence de-focus microscopy.The collective feature of the rotational motion was found and evidenced by the sharp change of the population of fluorophores undergoing rotational motion within a very narrow temperature range(named as the changing temperature,T c).The T c value was found to depend on film thickness and interfacial chemistry and the variation of the T c value is also dependent on the molecular weight of the polymer.The results demonstrate that the spatial confinement effect enhances the segmental mobility near the polymer chain-ends while the interfacial attraction restricts the segmental motion inside the thin film.展开更多
基金This work was supported by the National Natural Science Foundation of China （Grant No. 50271038）the Key Research Project Foundation of Shaanxi Normal University of China （No. 200403） Specialized Research Fund for the Doctoral Program of Higher Education of China （No. 20050698017）.
文摘A novel materials design procedure based on the co-doping of metal nanoparticle and azo dye compound （MNPADC） is developed to improve the properties of functional molecules. The synthesized materials were characterized by transmission electron micrograph （TEM）, ultraviolet-visible absorption spectra （UV-Vis） and fluorescence spectra （FS）. It was found that the fluorescence intensity of methyl orange （MO） was enhanced by 5 times in the aqueous composite system doped with silver nanoparticles whereas it was reduced by 15% and 20% in composite films with co-mixing and coating structures, respectively. The results indicate that the properties of functional molecules can be greatly improved in composite film with supra molecular structure and that the procedure presented here is effective.
基金supported by National Natural Science Foundation of China(21103039)Research Fund for the Doctoral Program of Higher Education of China (20110111120008)
文摘In recent years, immense interest has been paid to the biomolecular architecture with the aim of protein assembly in two di- mensions on solid substrates, and the constructions of clay-protein ultrathin films （CPUFs） are particularly concerned. This paper gives an overview of the recent research concerning the protein molecules （lysozyme, papain, protamine, bovine serum albumin） immobilized on clay mineral （Na-saponite） platelets and assembled in monolayered or multilayered hybrid ultrafilms or nanofilms. Two techniques including alternate layer-by-layer （LbL） assembly and the Langmuir-Blodgett （LB） are de- scribed in detail. A variety of means, including UV-vis absorption, attenuated total reflectance Fourier transform infrared （ATR-FTIR） spectroscopy, XRD, AFM and surface chemistry techniques, have been described for characterization of the films in terms of quantification of protein and clay. The result reveals that electrostatic interaction is a prominent but not the only driving force in CPUF construction. In the case of LB technique, we managed to manipulate the elementary clay mineral platelets （1.3 nm in thickness） and assemble proteins into CPUFs with the aid of surfactants, and the formation of CPUFs was monitored via surface pressure vs. time （a--t） kinetics curves and surface pressure vs. area （a--A） isotherms. The factors that in- fluence protein adsorption on the clay layer, such as surfactants, the concentration of clay, equilibrium time, categories of pro- tein, and injection methods, were investigated. The parameters such as protein amount （nS）, packing density （O）, and average surface area per molecule （.（2） of deposited CPUFs were measured via method of surface chemistry and spectroscopy. By comparing the results of surface chemistry with those of adsorption experiments, we demonstrate that the surface chemistry method is a useful tool in investigating CPUFs. We also found that the water soluble protein molecules could form protein-clay hybrid monolayer over the dilute clay dispersions without addition of surfactants, and CPUFs containing elementary clay sheets and protein with great homogeneity were easily prepared by controlling certain surface pressure. To investigate the bio-catalytic performance of the immobilized lysozyme in CPUFs, we deposited CPUFs onto a cover glass, and installed the cover glass in a flow cell-grown reactor for Comamonas testosteroni （WDL7-GFP） incubation. The results show that the pro- liferation of WDL7-GFP is greatly suppressed by lysozyme, which demonstrates that lysozyme still retains its bioactivity after it is immobilized in the CPUFs.
基金supported by the Natural Sciences and Engineering Council of Canada (NSERC)the Fonds de recherches du Québec-Nature et Technologies (FQRNT)
文摘Many technological applications require templates with nanoscale patterns.Block copolymer self-assembly is a method of choice for obtaining a large variety of such patterns,with greatest flexibility achieved when combined with a supramolecular approach.One of the ways to fabricate block copolymer templates is the Langmuir-Blodgett (LB) technique.Here,we briefly summarize recent work with LB films of polystyrene-poly(4-vinyl pyridine) (PS-P4VP) mixed with 3-n-pentade cylphenol (PDP),illustrating the different types of patterns possible and the principles governing them.One interesting pattern that can be easily achieved with this system is the so-called "nanostrand network",which,when used as a template for gold deposition,can produce double striped lines of gold.Here,we show how this pattern can be modified by acetone swelling to give rise to gold monolayer ribbons with internal structure.The results also suggest new insights into the early stages of morphology formation at the air/water interface.
文摘Enabling the use of rationally designed thin films in technological devices is a recognized goal in materials science. However, constructing such thin films using highly ordered supramolecular architectures with well-controlled size and growth direction has remained an elusive target. Here, we introduce a layer-by- layer protocol to grow hybrid thin films of molecule-based magnetic conductors comprising arachidic acid and donor bis（ethylenedioxy）tetrathiafulvalene （BEDO-TTF） as the organic component and Cu/Gd complexes as the inorganic component. The construction of layered hybrid thin films was achieved at ambient conditions by employing the Langmuir-Blodgett method, which provides good control over film thickness and packing of molecules in the monolayer. As demonstrated by X-ray diffraction, these films are crystalline with distinct organic and inorganic sublattices, where the BEDO-TTF molecular layer is interfaced with the inorganic layer. Due to the flexibility of the Langmuir-Blodgett deposition technique, this result indicates a route toward the preparation of well-ordered films with various functionalities, determined by the choice of the inorganic compound that is combined with the π-unit of BEDO-TFF. Moreover, the ability to deposit films on a variety of substrates establishes the potential for lower-cost device fabrication on inexpensive substrates.
基金supported by the National Basic Research Program of China(2012CB821500)the National Natural Science Foundation of China(20925416)
文摘Rotational motion of fluorophores chemically attached to polystyrene chain-ends in ultra-thin films on solid substrates was studied by single-molecule fluorescence de-focus microscopy.The collective feature of the rotational motion was found and evidenced by the sharp change of the population of fluorophores undergoing rotational motion within a very narrow temperature range(named as the changing temperature,T c).The T c value was found to depend on film thickness and interfacial chemistry and the variation of the T c value is also dependent on the molecular weight of the polymer.The results demonstrate that the spatial confinement effect enhances the segmental mobility near the polymer chain-ends while the interfacial attraction restricts the segmental motion inside the thin film.
