Effect of surface modification on the electrical properties of TiO2 and SnO2 nanopowders

1997 ◽  
Vol 501 ◽  
Author(s):  
Fabienne Chancel ◽  
Jérôme Tribout ◽  
Marie-Isabelle Baraton
Keyword(s):  
Surface Modification ◽  
Electrical Properties ◽  
Gas Sensors ◽  
Tin Dioxide ◽  
Free Carriers ◽  
Conductivity Variation ◽  
Ft Ir ◽  
Effect Of Surface ◽  
Ft Ir Spectroscopy

ABSTRACTThe surface modification of titania and tin dioxide nanopowders by hexamethyldisilazane and hexamethyldisiloxane grafting has been followed in situ by FT-IR spectroscopy. A grafting mechanism is proposed for both compounds and the formation of new surface species is discussed. Since TiO2 and SnO2 are widely used in chemical gas sensors due to their electrical properties, the respective behaviors of the non-grafted and grafted samples in reducing (CO) environment as well as the humidity effects are compared. Because the transmitted IR energy depends on the concentration of the free carriers, a correlation between the electrical conductivity variation and the perturbation of the IR spectra is attempted.

Study on Surface Modification of Mica Pearl Pigment with Stearic Acid

2016 ◽  
Vol 852 ◽  
pp. 774-781
Author(s):  
Qian Yu ◽  
Yong Le Ke ◽  
Xu Kun Tan ◽  
Gao Dan Luo ◽  
Sheng Bo Han ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Surface Modification ◽  
Stearic Acid ◽  
X Ray ◽  
Electrostatic Spraying ◽  
Ft Ir ◽  
Powder Spraying ◽  
Scanning Electron ◽  
Effect Of Surface ◽  
Ft Ir Spectroscopy

Using stearic acid as modifier, the surface of mica pearl pigment organic modification technology are discussed in this paper, and the application effect of after modified. X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and Scanning electron microscope (SEM) were used to characterize the effect of surface modification. Electrostatic spraying test (EST) and Chromatism test were used to characterize the application effect of after modified. The results showed that the stearic acid could be successfully grafted on the surface of mica pearl pigment and enhanced hydrophobicity. Besides, it was demonstrated that the mica pearl pigment treated with stearic acid could make the value of chromatism deviation are low, which also could significantly improve the powder spraying ratio at low spray voltages.

Study on the Surface Modification of Nano-TiO2

2013 ◽  
Vol 641-642 ◽  
pp. 529-533
Author(s):  
Dong Mei Zhao ◽  
Gui Min Qian ◽  
Shan Yun ◽  
Qian Qian Song ◽  
Dong Hai Zhu ◽  
...  
Keyword(s):  
Surface Modification ◽  
Measuring Instrument ◽  
Optical Contact ◽  
Nano Tio2 ◽  
X Ray ◽  
Transmission Electron ◽  
Angle Measuring ◽  
Ft Ir ◽  
Effect Of Surface ◽  
Ft Ir Spectroscopy

KH550 modified ZnO/TiO2 was prepared. The surface of nano-TiO2 was coated with ZnO derived from Na2Zn(OH)4 via a heterogeneous nucleation process, and coupling agent KH550 was used to treat the surface of ZnO/TiO2. Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and Optical contact angle measuring instrument were used to characterize the effect of surface modification. The results showed that the surface of nano-TiO2 was coated by ZnO nanoparticles; After modified by the KH550, the modified ZnO/TiO2 showed better dispersion in water-toluene solution; and the surface of modified ZnO/TiO2 became more hydrophobic-lipophilic than that of modified uncoated nano-TiO2.

scholarly journals Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by in-situ FT-IR Spectroscopy

2019 ◽  
Author(s):  
Xi Yang
Keyword(s):  
Ir Spectroscopy ◽  
Reaction Rate ◽  
Interfacial Polymerization ◽  
Reaction System ◽  
Reaction Rates ◽  
Water Permeation ◽  
Ft Ir ◽  
Trimesoyl Chloride ◽  
Ft Ir Spectroscopy

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize the nanofiltration (NF) membrane. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies are applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer; (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in-situ FT-IR spectroscopy was firstly used to monitor the IP reaction of PIP/TMC reaction system, with hydrophilic interlayers or macromolecular additives. Moreover, we study the formed polyamide layer growth on the substrate, in a real-time manner. The in-situ FT-IR experimental results confirm that the IP reaction rates are effectively suppressed and the formed polyamide thickness reduces from 138±24 nm to 46±2 nm. Furthermore, the optimized NF membrane with excellent performance are consequently obtained, which include the boosted water permeation flux about 141~238 (L·m2·h/MPa) and superior salt rejection of Na2SO4 > 98.4%.

Ethylene polymerization on a SiH4-modified Phillips catalyst: detection of in situ produced α-olefins by operando FT-IR spectroscopy

2012 ◽  
Vol 14 (7) ◽  
pp. 2239 ◽  
Author(s):  
Caterina Barzan ◽  
Elena Groppo ◽  
Elsje Alessandra Quadrelli ◽  
Vincent Monteil ◽  
Silvia Bordiga
Keyword(s):  
Ir Spectroscopy ◽  
Ethylene Polymerization ◽  
Phillips Catalyst ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

scholarly journals Polyaniline Deposition on the Surface of Cotton Fibers: Structural Studies, Swelling Behavior, and Water Absorption Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Tesfamariam Teklu ◽  
Teklit Kidane Gebremedhin ◽  
Amanual Hadera Tesfay ◽  
Asfaw Gebretsadik Gebru ◽  
Ykalo Hadush Desta ◽  
...  
Keyword(s):  
Water Absorption ◽  
Electromagnetic Interference ◽  
Structural Changes ◽  
Natural Fibers ◽  
Control Sample ◽  
Cotton Fibers ◽  
Surface Deposition ◽  
Ft Ir ◽  
Effect Of Surface

Polyaniline-modified natural fibers have been recognized as promising candidates for conductive clothes, UV protection, and electromagnetic interference shielding. Hence, the purpose of this study was to investigate the effect of surface deposition of cotton fibers using polyaniline via in situ polymerization, and preceding structural changes were further screened by FT-IR, UV-Vis, TGA, SEM/EDX, and conductivity in comparison with bare cotton fibers used as the control sample. Polyaniline was introduced on the surface of cotton fibers as a conductive form, which was confirmed by electrical conductivity (1.54 × 10−4 Scm−1) equivalent to semiconductor materials. Detection of particular peaks at NKα 0.379 keV and ClKα 2.621 keV from EDX analysis revealed the introduction of nitrogen and chlorine, respectively. Polyaniline deposition on the cotton surface was successful to introduce hydrophobic environment to the system to enhance resistance to water absorption meaningfully.

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