Ti O2-organic multilayered nanocomposite films were deposited on a self-assembled monolayer-coated silicon substrate based on layer-by-layer technique and chemical bath deposition method by a hydrolysis of Ti Cl4 in a...Ti O2-organic multilayered nanocomposite films were deposited on a self-assembled monolayer-coated silicon substrate based on layer-by-layer technique and chemical bath deposition method by a hydrolysis of Ti Cl4 in an acid aqueous solution. The chemical compositions, surface morphologies and mechanical properties of the films were investigated by X-ray photoelectron spectrometer(XPS), scanning electron microscopy(SEM) and nanoindentation depth-sensing technique, respectively. The results indicate that the major chemical compositions of the films are Ti and O. The principal mechanism for the nucleation and growth of the films is homogeneous nucleation, and the layer number of films has great influence on the surface morphology and roughness of the films. In addition, mechanical nanoindentation testing presents a significant increase in hardness and fracture toughness of titanium dioxide multilayered films compared with single-layer titanium dioxide thin film.展开更多
Pyrene was chemically assembled on a glass plate surface in a monolayer manner via spacers con-taining triethylenetetramine (TETA) subunits. It has been demonstrated that the fluorescence emission of the film is sensi...Pyrene was chemically assembled on a glass plate surface in a monolayer manner via spacers con-taining triethylenetetramine (TETA) subunits. It has been demonstrated that the fluorescence emission of the film is sensitive to the presence of trace amount of nitroaromatic compound (NAC) vapors. As discovered in the present work, the response selectivity of the pyrene-functionalized film depends on the length of the spacer, the vapor pressure of a given NAC, and the quencher size. The film shows faster response to those quenchers which have higher vapor pressure and smaller size. Compared to the film with shorter spacers, the present film with longer flexible spacers shows a slower response to the NACs, but higher selectivity to the quencher size. Additionally, the detection limits to common ex-plosives in vapor phase, 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT), are 7.14×10-12 and 5.49×10-11 g·mL-1, respectively. Further examinations indicated that the sensing process is fully re-versible, and the vapors of those common interference such as benzene, toluene, ethanol, and perfume have little effect upon the sensing performances of the film.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
基金Projects(51204036,51234009)supported by the National Natural Science Foundation of ChinaProject(2014CB643405)supported by the National Basic Research Program of China
文摘Ti O2-organic multilayered nanocomposite films were deposited on a self-assembled monolayer-coated silicon substrate based on layer-by-layer technique and chemical bath deposition method by a hydrolysis of Ti Cl4 in an acid aqueous solution. The chemical compositions, surface morphologies and mechanical properties of the films were investigated by X-ray photoelectron spectrometer(XPS), scanning electron microscopy(SEM) and nanoindentation depth-sensing technique, respectively. The results indicate that the major chemical compositions of the films are Ti and O. The principal mechanism for the nucleation and growth of the films is homogeneous nucleation, and the layer number of films has great influence on the surface morphology and roughness of the films. In addition, mechanical nanoindentation testing presents a significant increase in hardness and fracture toughness of titanium dioxide multilayered films compared with single-layer titanium dioxide thin film.
基金the National Natural Science Foundation of China (Grant No. 20674048)the Ministry of Education of China (Grant Nos. 03148 and 306015)+1 种基金"863" Program from Ministry of ScienceTechnology of China (Grant No. 2007AA032349)
文摘Pyrene was chemically assembled on a glass plate surface in a monolayer manner via spacers con-taining triethylenetetramine (TETA) subunits. It has been demonstrated that the fluorescence emission of the film is sensitive to the presence of trace amount of nitroaromatic compound (NAC) vapors. As discovered in the present work, the response selectivity of the pyrene-functionalized film depends on the length of the spacer, the vapor pressure of a given NAC, and the quencher size. The film shows faster response to those quenchers which have higher vapor pressure and smaller size. Compared to the film with shorter spacers, the present film with longer flexible spacers shows a slower response to the NACs, but higher selectivity to the quencher size. Additionally, the detection limits to common ex-plosives in vapor phase, 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT), are 7.14×10-12 and 5.49×10-11 g·mL-1, respectively. Further examinations indicated that the sensing process is fully re-versible, and the vapors of those common interference such as benzene, toluene, ethanol, and perfume have little effect upon the sensing performances of the film.
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.
