The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
Chien-hsiang Chang - One of the best experts on this subject based on the ideXlab platform.
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On the characteristics of mixed Langmuir monolayer templates containing dipalmitoyl phosphatidylcholine for gold nanoparticle formation
Colloids and Surfaces B: Biointerfaces, 2009Co-Authors: Fang W. Hsiao, Yuh Lang Lee, Chien-hsiang ChangAbstract:Mixed Langmuir monolayers containing dipalmitoyl phosphatidylcholine (DPPC) were applied as two-dimensional templates to incorporate with gold precursor AuCl4-in the subphases. The organic monolayer templates were then transferred onto solid substrates to form ultra-thin films by the Langmuir-Blodgett (LB) deposition technique. With an UV irradiation approach, gold nanoparticles were thus fabricated in the LB films of monolayer templates. Characteristics of the monolayer templates were studied by the Surface Pressure-Area Isotherm measurements and Brewster angle microscopy (BAM) observation. The factors affecting the formation of gold nanoparticle structures in the LB films of organic monolayer templates were elucidated by the atomic force microscopy (AFM). The monolayer Isotherms and BAM images suggested that by changing the gold precursor concentration in the subphase, one could control the adsorption behavior of the gold precursor onto the monolayer templates. It was found that the association of the gold precursor with a pure DPPC monolayer template resulted in an unstable Langmuir monolayer, which was inappropriate for the following LB deposition. With the presence of n-hexadecanol in a DPPC monolayer, the monolayer template stability and corresponding LB deposition quality could be tremendously improved. Moreover, the distribution of DPPC molecules in the monolayer templates was possible to be regulated by the addition of n-hexadecanol, and the association behavior of the gold precursor with the monolayer templates was thus controlled. The AFM analysis then indicated that the number and size of gold nanoparticles fabricated in the LB films of the mixed DPPC/n-hexadecanol monolayer templates by a photoreduction reaction could be manipulated by the mole fraction of n-hexadecanol and UV irradiation time. © 2009 Elsevier B.V. All rights reserved.
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On the Langmuir-Blodgett transfer of copper tetra-tert-butyl phthalocyanine monolayers in the presence of arachidic acid
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002Co-Authors: Chingwen Sheu, Chien-hsiang Chang, I-hsun Ku, Yu Min YangAbstract:Abstract This study investigated the influence of arachidic acid as a transfer promoter on the deposition of multilayer copper tetra-tert-butyl phthalocyanine (CuTTBPc) Langmuir–Blodgett (L–B) films on both hydrophilic glass and hydrophobic silanized-glass substrates. With the addition of arachidic acid in a CuTTBPc monolayer at the air/water interface, two transitions corresponding to monolayer collapse were observed in the Surface pressure–area Isotherm. However, the added arachidic acid had no effect on area relaxation of a CuTTBPc monolayer at 20 mN m−1. The up-stroke L–B transfer of a CuTTBPc monolayer at 20 mN m−1 onto a glass substrate was perfect with a transfer ratio of 1.0, but most of the deposited film respread onto the interface during the following down-stroke deposition. It appears that the addition of arachidic acid with a molar fraction of 0.5 caused insignificant influence on the continuous L–B deposition of CuTTBPc films on glass substrates. On a silanized-glass substrate, imperfect Y-type multilayer CuTTBPc L–B films could be fabricated with transfer ratios around 0.5. The presence of arachidic acid in a CuTTBPc monolayer may considerably improve the down-stroke first layer deposition with a transfer ratio close to one. Moreover, the following up-stroke deposition quality of the L–B films was strongly affected by the molar fraction of arachidic acid.
Teiichiro Ogawa - One of the best experts on this subject based on the ideXlab platform.
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second harmonic generation from mixed films of rhodamine dye and arachidic acid at the air water interface correlation with spectroscopic properties
Langmuir, 2001Co-Authors: Oksana Slyadneva, M N Slyadnev, And Akira Harata, Teiichiro OgawaAbstract:Mixed insoluble monolayers of bis(N-ethyl,N-octadecyl)rhodamine perchlorate (RhC18) and arachidic acid (ArAc) at the air−water interface were characterized by Surface pressure−area Isotherm, second harmonic generation (SHG), and reflection spectroscopy studies. The analysis of Surface pressure−area Isotherms of mixed RhC18/ArAc layers provided evidence that there was a high degree of miscibility of film components and a strong interaction among them. A new band was found to appear on the blue side of the reflection spectrum after an increase in both the concentration of ArAc in the layer and the applied Surface pressure. This new band was assigned to dye aggregates, where spontaneous formation in the gaslike region was promoted by the presence of ArAc and induced by compression in the region of the continuous monolayer. Both in gaslike and in compressed film, the formation of blue-shifted aggregates coincided with the increase of the SHG response of the monolayer. Resonance SHG enhancement was proven to b...
M N Slyadnev - One of the best experts on this subject based on the ideXlab platform.
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second harmonic generation from mixed films of rhodamine dye and arachidic acid at the air water interface correlation with spectroscopic properties
Langmuir, 2001Co-Authors: Oksana Slyadneva, M N Slyadnev, And Akira Harata, Teiichiro OgawaAbstract:Mixed insoluble monolayers of bis(N-ethyl,N-octadecyl)rhodamine perchlorate (RhC18) and arachidic acid (ArAc) at the air−water interface were characterized by Surface pressure−area Isotherm, second harmonic generation (SHG), and reflection spectroscopy studies. The analysis of Surface pressure−area Isotherms of mixed RhC18/ArAc layers provided evidence that there was a high degree of miscibility of film components and a strong interaction among them. A new band was found to appear on the blue side of the reflection spectrum after an increase in both the concentration of ArAc in the layer and the applied Surface pressure. This new band was assigned to dye aggregates, where spontaneous formation in the gaslike region was promoted by the presence of ArAc and induced by compression in the region of the continuous monolayer. Both in gaslike and in compressed film, the formation of blue-shifted aggregates coincided with the increase of the SHG response of the monolayer. Resonance SHG enhancement was proven to b...
Oksana Slyadneva - One of the best experts on this subject based on the ideXlab platform.
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Second harmonic generation from insoluble films of a rhodamine dye at the air-water interface: effect of sodium dodecylsulfate.
Journal of colloid and interface science, 2003Co-Authors: Oksana Slyadneva, Akira Harata, Yoshihiko HatanoAbstract:Abstract The second harmonic generation (SHG) from the insoluble monolayers of bis-(N-ethyl, N-octadecyl)rhodamine perchlorate (RhC18) formed on the Surface of sodium dodecylsulfate (SDS) solutions of different concentrations has been studied. An enhancement of the second harmonic response was observed in the mixed films of RhC18/SDS compared to the pure-dye layer. To clarify the origin of the phenomenon, the films were characterized by Surface pressure–area Isotherm and reflection–absorption spectroscopy studies. The analysis of Surface pressure–area Isotherms of RhC18/SDS layers showed that incorporated SDS molecules essentially influence the rheological properties of the dye monolayer. The film parameters, such as the molecular Surface area, maximum Surface pressure, and solid-condensed phase composition, are the functions of SDS bulk concentration. A joint analysis of the SHG results and the reflection–absorption spectra revealed that the structural ordering within films was responsible for the enhancement of the nonlinear optical response, whereas the contributions from the spectral shifts and increased absorption upon aggregate formation are of less importance.
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second harmonic generation from mixed films of rhodamine dye and arachidic acid at the air water interface correlation with spectroscopic properties
Langmuir, 2001Co-Authors: Oksana Slyadneva, M N Slyadnev, And Akira Harata, Teiichiro OgawaAbstract:Mixed insoluble monolayers of bis(N-ethyl,N-octadecyl)rhodamine perchlorate (RhC18) and arachidic acid (ArAc) at the air−water interface were characterized by Surface pressure−area Isotherm, second harmonic generation (SHG), and reflection spectroscopy studies. The analysis of Surface pressure−area Isotherms of mixed RhC18/ArAc layers provided evidence that there was a high degree of miscibility of film components and a strong interaction among them. A new band was found to appear on the blue side of the reflection spectrum after an increase in both the concentration of ArAc in the layer and the applied Surface pressure. This new band was assigned to dye aggregates, where spontaneous formation in the gaslike region was promoted by the presence of ArAc and induced by compression in the region of the continuous monolayer. Both in gaslike and in compressed film, the formation of blue-shifted aggregates coincided with the increase of the SHG response of the monolayer. Resonance SHG enhancement was proven to b...
Fang W. Hsiao - One of the best experts on this subject based on the ideXlab platform.
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On the characteristics of mixed Langmuir monolayer templates containing dipalmitoyl phosphatidylcholine for gold nanoparticle formation
Colloids and Surfaces B: Biointerfaces, 2009Co-Authors: Fang W. Hsiao, Yuh Lang Lee, Chien-hsiang ChangAbstract:Mixed Langmuir monolayers containing dipalmitoyl phosphatidylcholine (DPPC) were applied as two-dimensional templates to incorporate with gold precursor AuCl4-in the subphases. The organic monolayer templates were then transferred onto solid substrates to form ultra-thin films by the Langmuir-Blodgett (LB) deposition technique. With an UV irradiation approach, gold nanoparticles were thus fabricated in the LB films of monolayer templates. Characteristics of the monolayer templates were studied by the Surface Pressure-Area Isotherm measurements and Brewster angle microscopy (BAM) observation. The factors affecting the formation of gold nanoparticle structures in the LB films of organic monolayer templates were elucidated by the atomic force microscopy (AFM). The monolayer Isotherms and BAM images suggested that by changing the gold precursor concentration in the subphase, one could control the adsorption behavior of the gold precursor onto the monolayer templates. It was found that the association of the gold precursor with a pure DPPC monolayer template resulted in an unstable Langmuir monolayer, which was inappropriate for the following LB deposition. With the presence of n-hexadecanol in a DPPC monolayer, the monolayer template stability and corresponding LB deposition quality could be tremendously improved. Moreover, the distribution of DPPC molecules in the monolayer templates was possible to be regulated by the addition of n-hexadecanol, and the association behavior of the gold precursor with the monolayer templates was thus controlled. The AFM analysis then indicated that the number and size of gold nanoparticles fabricated in the LB films of the mixed DPPC/n-hexadecanol monolayer templates by a photoreduction reaction could be manipulated by the mole fraction of n-hexadecanol and UV irradiation time. © 2009 Elsevier B.V. All rights reserved.