Search

Your search keyword '"Li, Bofu"' showing total 45 results
Start Over Author "Li, Bofu"
45 results on '"Li, Bofu"'

18. Aggregation of silver particles trapped at an air-water interface for preparing new SERS active substrates

Author

Hu, Jiawen, Bing, Zhao, Fan, Yuguo, Li, Bofu, and Ozaki, Yukihiro

Subjects
Raman effect -- Research, Silver compounds -- Research, Chemicals, plastics and rubber industries
Abstract

A novel technique for the fabrication of active substrates of surface-enhanced Raman scattering (SERS) is proposed. It is observed that the silver particles themselves and the analyte-covered silver particles can be trapped at the air/water interface.

Published
2002

19. Molecular Orientation and Aggregation in the Langmuir-Blodgett Films of 4-[4′-(4″-Decyloxy Phenylazo) Naphthloxy] Butyl Trimethylammonium Dextran Sulfate Studied by Ultra-Violet and Infrared Spectroscopy

Author

Zhao Bing, Li Bofu, Xu Weiqing, Wu Yuqing, and Li Guowen

Subjects
chemistry.chemical_classification, Infrared spectroscopy, Chromophore, Photochemistry, Langmuir–Blodgett film, Atomic and Molecular Physics, and Optics, Analytical Chemistry, Crystallography, chemistry.chemical_compound, Hydrocarbon, chemistry, Bromide, Amphiphile, Monolayer, Spectroscopy, Alkyl
Abstract

Infrared transmission, Reflectance-Absorption (RA) and Ultra-Violet (UV) spectra were measured for mono-and multi-layers Langmuir-Blodgett (LB) films of 4-[4′-(4″-decyIoxy phenylazo)naphthloxy] butyl trimethylammonium bromide formed with SDS to study the molecular orientation and aggregation. The results indicate that the compound do not aggregate in the LB films, and the alkyl tail is nearly perpendicular to the substrate surface and the chromorphore part adopts trans-zigzag conformation. These results also suggest that the molecular orientation and aggregation are not depend upon the number of monolayers The comparison of infrared transmission and RA spectra indicates that the hydrocarbon chain is nearly perpendicular to the substrate surface, but the two rings in the chromophore part are tilted considerably from the surface normal.

Published
1998

20. Structure and Orientation of 1-Hydroxyl-5-Hexadecyloxy-Naphthalene LB Films Studied By UV-VIS and FTIR Spectroscopy

Author

Li Xiaoling, Li Guowen, Xu Weiqing, Wu Yuqing, Zhao Bing, and Li Bofu

Subjects
Absorption spectroscopy, Chemistry, Analytical chemistry, Atomic and Molecular Physics, and Optics, Analytical Chemistry, chemistry.chemical_compound, Ultraviolet visible spectroscopy, Monomer, Monolayer, Absorption (chemistry), Fourier transform infrared spectroscopy, Spectroscopy, Naphthalene
Abstract

Ultraviolet-visible (UV-Vis), infrared transmission, and reflection absorption(RA) spectra have been measured for one-and multi-monolayer Langmuir-Blodgett(LB) films of C16H3330Naph(1,5)OH at various temperature to investigate dependencies of the aggregation and phase transitions on the number of monolayers. The UV-vis spectra of the LB films have revealed that the C16H33ONaph(1,5)OH forms aggregates in the LB film. From the temperature dependence of UV-vis absorption spectra, it is clear that the aggregate is gradual converted to monomer upto 80 °C. A comparison of the infrared transmission and RA spectra reveals that the hydrocarbon chains are tilted considerably in the LB film. As for the naphthalene ring part, the result suggest that the ring plane is oriented approximately perpendicular to the substrate surface. The Temperature dependence of infrared transmission spectra have been measured for 1-, 3-, and 11-monolayer LB films to investigate dependence of phase transitions on the number of m...

Published
1998

41. Effects of monomer structure on the morphology of polymer network and the electro-optical property of reverse-mode polymer-stabilized cholesteric texture.

Author

Yin, Yuhai, Li, Wenbo, Cao, Hui, Guo, Jinbao, Li, Bofu, He, Simin, Ouyang, Canbin, Cao, Ming, Huang, Hua, and Yang, Huai

Subjects
MONOMERS, POLYMER networks, CROSSLINKED polymers, ELECTROOPTICS, PHOTOPOLYMERIZATION
Abstract

The article presents a study on the effects of monomer structure on the morphology of polymer network and the electro-optical property of reverse-mode polymer-stabilized cholesteric texture (PSCT). The study prepared polymer network/liquid crystal (LC) composite from photopolymerization of the acrylate monomers. It found that the acrylate monomer with flexible pacers formed fiber-like polymer network with better orientation than the acrylate monomer without flexible pacers.

Published
2009
Full Text
View/download PDF

42. Studies on electro-optical properties of polymer matrix/LC/SiO2 nanoparticles composites.

Author

Li, Wenbo, Zhu, Mengjun, Ding, Xiaokang, Li, Bofu, Huang, Wei, Cao, Hui, Yang, Zhou, and Yang, Huai

Subjects
POLYMER liquid crystals, NANOPARTICLES, LIQUID crystal displays, LIGHT scattering, PHOTOPOLYMERIZATION
Abstract

The article presents a study that investigated the electro-optical properties of the polymer-dispersed liquid crystal (PDLC) materials with added organic SiO2 nanoparticles and explain the changes in the switching times and voltages. Results show that nematic liquid crystal (LC)/photopolymerizable monomers /SiO2 nanoparticles composites are promising for LCD and other electro-optical applications. It notes that further research to optimize these devices is in progress.

Published
2009
Full Text
View/download PDF

43. Study on the photo-induced interfacial charge transfer in TiO 2 /Fe 2 O 3 heterostructured composite film

Author

Zhang, Xintong, Cao, Yaan, Kan, Shihai, Chen, Yongmei, Tang, Jun, Jin, Haiyan, Bai, Yubai, Xiao, Liangzhi, Li, Tiejin, and Li, Bofu

Abstract

Heterostructured TiO 2 /Fe 2 O 3 composite film was obtained by spin-coating α -Fe 2 O 3 hydrosol on the TiO 2 nanoparticulate film prepared by the sol-gel method. The composite film was characterized by surface photovoltaic spectroscopy (SPS) and electric-field-induced surface photovoltaic spectroscopy (EFSPS), and the results showed that the composite film had the extended photovoltaic response which can be modified by the external electric field. Based on these results, a photoinduced interfacial charge transfer mechanism was deduced and the energy band structure of the composite film was concluded.

Published
1998
Full Text
View/download PDF

45. Raman spectroscopic investigation of the single-monolayer Langmuir–Blodgett film of C16NaphOH and C10AzoNaphC4N-SDS

Author

Wu, Yuqing, Zhao, Bing, Xu, Weiqing, Li, Guowen, and Li, Bofu

Subjects
*RAMAN effect, *MULTILAYERED thin films, *FLUORESCENCE
Abstract

Raman spectra were measured for Langmuir–Blodgett (LB) films of C16NaphOH and C10AzoNaphC4N-SDS on Calcium Fluorite substrate for the first time. In order to find out favorable excitation condition, Raman spectra of the single and multi-monolayer LB films excited at different lines at 244, 514, 633 and 778 nm are recorded and compared in the present study. Raman spectrum of the monolayer LB film of C16NaphOH excited by 244 nm demonstrate that excellent signal to noise is achieved even for one monolayer LB film with an extremely short integrating time as 60 s because of being resonantly enhanced, while no meaningful spectra were recorded under the same condition for the monolayer LB film of C10AzoNaphC4N-SDS because of burning. Using a HeNe 633 nm excitation the problem with strong substrate fluorescence was partially solved, since under these conditions this fluorescence is mainly outside the fingerprint region of the LB film molecules (1000–2000 cm−1). Therefore by using the HeNe laser excitation, Raman spectra with high signal to noise ratio of LB films of C16NaphOH were collected and shown in this paper. These findings stress again the necessity to define an appropriate Raman system for this special application of LB film diagnosis. [Copyright &y& Elsevier]

Published
2003
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results