Nanostructured Films Employed as Sensing Units in an "Electronic Tongue" System

2007 ◽  
Vol 7 (2) ◽  
pp. 510-514 ◽  
Author(s):  
B. A. da Silva ◽  
P. A. Antunes ◽  
D. Pasquini ◽  
A. A. S. Curvelo ◽  
R. F. Aroca ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Electronic Tongue ◽  
Langmuir Monolayers ◽  
Metallic Ions ◽  
Ultrapure Water ◽  
Molecular Area ◽  
Nanostructured Films ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Lignin Macromolecule

Nanostructured films of lignin (macromolecule extracted from sugar cane bagasse), polypyrrole (conducting polymer) and bis butylimido perylene (organic dye) were used in the detection of trace levels of fluorine (from H2SiF6), chlorine (from NaClO), Pb+2, Cu+2, and Cd+2 in aqueous solutions. Langmuir monolayers on ultrapure water were characterised by surface pressure-mean molecular area (Π-A) isotherms. Langmuir-Blodgett (LB) films were transferred onto gold interdigitated electrodes and used as individual sensing units of an electronic tongue system. Impedance spectroscopy measurements were taken with the sensor immersed into aqueous solutions containing the ions described above in different molar concentrations. Fourier transform infrared absorption (FTIR) was employed to identify possible interactions between the LB films and the analytes in solution, and no significant changes could be observed in the FTIR spectra of BuPTCD and Ppy. Therefore, the results for lignin point to an interaction involving the electronic cloud of the phenyl groups with the metallic ions.

Nanostructured Films Employed as Sensing Units in an "Electronic Tongue" System

2007 ◽  
Vol 7 (2) ◽  
pp. 510-514 ◽  
Author(s):  
B. A. da Silva ◽  
P. A. Antunes ◽  
D. Pasquini ◽  
A. A. S. Curvelo ◽  
R. F. Aroca ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Electronic Tongue ◽  
Langmuir Monolayers ◽  
Metallic Ions ◽  
Ultrapure Water ◽  
Molecular Area ◽  
Nanostructured Films ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Lignin Macromolecule

Nanostructured films of lignin (macromolecule extracted from sugar cane bagasse), polypyrrole (conducting polymer) and bis butylimido perylene (organic dye) were used in the detection of trace levels of fluorine (from H2SiF6), chlorine (from NaClO), Pb+2, Cu+2, and Cd+2 in aqueous solutions. Langmuir monolayers on ultrapure water were characterised by surface pressure-mean molecular area (Π-A) isotherms. Langmuir-Blodgett (LB) films were transferred onto gold interdigitated electrodes and used as individual sensing units of an electronic tongue system. Impedance spectroscopy measurements were taken with the sensor immersed into aqueous solutions containing the ions described above in different molar concentrations. Fourier transform infrared absorption (FTIR) was employed to identify possible interactions between the LB films and the analytes in solution, and no significant changes could be observed in the FTIR spectra of BuPTCD and Ppy. Therefore, the results for lignin point to an interaction involving the electronic cloud of the phenyl groups with the metallic ions.

Nanostructured LB films developed from poly(p-acryloylaminophenylmethylphosphonic) acid

2016 ◽  
Vol 1819 ◽  
Author(s):  
Rosa E. Lazo-Jiménez ◽  
José A. Chávez-Carvayar ◽  
Ana M. Herrera-González ◽  
Valentin Islas-Pérez ◽  
María P. Carreón-Castro
Keyword(s):  
Multilayer Films ◽  
Molecular Area ◽  
Lb Films ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Glass Substrates ◽  
Atomic Force ◽  
Air Water Interface ◽  
Langmuir Blodgett Films ◽  
Ordered Nanostructures

ABSTRACTIn this paper, the formation of Langmuir-Blodgett films of poly(p-acryloylaminophenylmethylphosphonic) acid polymers, with general formula (C10H12NPO4)n are reported. The Langmuir-Blodgett (LB) technique was used for building ordered nanostructures in molecular assemblies of these polymers, which were able to form stable films. At the air-water interface, these polymers (with low and high molecular weight) formed Langmuir (L) monolayers, which were characterized by surface pressure versus molecular area (π-A) isotherms and Brewster´s Angle Microscopy (BAM). Using the LB method, molecular mono and multilayer films of these polymers were prepared and transferred onto glass substrates forming Z-type multilayers, with a transfer ratio close to unity. These LB films were characterized by Atomic Force Microscopy (AFM).

Nanoparticle assembly following Langmuir–Hinshelwood kinetics on a Langmuir film and chain networks captured in LB films

2015 ◽  
Vol 17 (11) ◽  
pp. 7386-7394 ◽  
Author(s):  
Lasya Maganti ◽  
Madhuri Jash ◽  
Anju Nair ◽  
T. P. Radhakrishnan
Keyword(s):  
Metal Nanoparticles ◽  
Nanoparticle Assembly ◽  
Deposition Pressure ◽  
Langmuir Film ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films ◽  
Positively Charged

Negatively charged metal nanoparticles assemble as chain networks through Langmuir–Hinshelwood kinetics on a Langmuir film of positively charged amphiphiles. The extension of the networks captured in Langmuir–Blodgett films is tuned by the deposition pressure.

Photoelectric Cells of Merocyanine Langmuir-Blodgett Films Utilizing Surface Plasmon Excitations

2001 ◽  
Vol 708 ◽  
Author(s):  
Keizo Kato ◽  
Futoshi Takahashi ◽  
Kazunari Shinbo ◽  
Futao Kaneko ◽  
Takashi Wakamatsu
Keyword(s):  
Thin Films ◽  
Surface Plasmon ◽  
Short Circuit ◽  
Schottky Diodes ◽  
Attenuated Total Reflection ◽  
Dielectric Constants ◽  
Type I ◽  
Type Ii ◽  
Lb Films ◽  
Langmuir Blodgett

ABSTRACTShort-circuit photocurrents (ISC) due to surface plasmon (SP) excitations have been investigated for the photoelectric cells using Langmuir-Blodgett (LB) films of merocyanine (MC) dye. The MC dye exhibits p-type conduction, and the Schottky and Ohmic contacts are obtained at the interfaces between MC LB films and Al thin films and between MC LB films and Ag thin films, respectively. Since the Schottky diodes show the photoelectric effects, the Schottky photoelectric cells have been constructed. The cells with two kinds of structures, that is, prism/Al/MC/Ag (type I) and prism/MgF2/Al/MC/Ag (type II), have been prepared. In the attenuated total reflection (ATR) method, the types I and II have the Kretschmann and both the Kretschmann and Otto configurations, respectively. SP has been resonantly excited at the interface between Ag and air for the type I and at the interfaces between MgF2 and Al between Ag and air for the type II. The ATR and the ISC properties have been simultaneously measured as a function of the incident angles of the laser beams. The peaks of the ISC have corresponded to the resonant angles of the ATR curves. The electric fields and optical absorptions in the cells have been also calculated using the dielectric constants and the film thicknesses obtained from the ATR measurements. The calculated absorptions in the MC layers as a function of the incident angles have corresponded to the results of ISC. It has been estimated that the ISC for both types I and II could be enhanced by the excitations of SP in the ATR configurations.

Emission Light Properties from Ag/Rhodamine-B LB Films Due to Surface Plasmon Excitations in the Kretschmann and Reverse Configurations

2000 ◽  
Vol 660 ◽  
Author(s):  
T. Nakano ◽  
H. Kobayashi ◽  
K. Shinbo ◽  
K. Kato ◽  
F. Kaneko ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Rhodamine B ◽  
Emission Angle ◽  
Attenuated Total Reflection ◽  
Peak Wavelength ◽  
Resonant Condition ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Kretschmann Configuration ◽  
Emission Light

ABSTRACTEmission light from Ag/ Rhodamine-B (RB) Langmuir-Blodgett (LB) films due to surface plasmon (SP) excitations has been investigated using the Kretschmann configuration of the attenuated total reflection (ATR) method and the reverse irradiation of laser beam from air to the samples. The conventional photoluminescence (PL) of the RB LB films showed a broad spectrum and the peak wavelength was about 600 nm. In the reverse irradiation, emission light was observed through the prism, and the intensities and the spectra strongly depended upon the emission angle where the light was observed. The wavelengths of the emission light became shorter as the emission angles increased. The relation between the wavelength and the emission angle agreed with the resonant condition of excitations of SPs in the Kretschmann configuration of ATR method. It was concluded that the emission light was caused by excitations of multiple SPs at the Ag/RB LB films.

Structural and Morphological Characterization of Ultrathin Films of an Asymmetric Polydiacetylene

1996 ◽  
Vol 440 ◽  
Author(s):  
H. C. Wang ◽  
D. W. Cheong ◽  
J. Kumar ◽  
C. Sung ◽  
S. K. Tripathy
Keyword(s):  
Second Harmonic ◽  
Morphological Characterization ◽  
Lb Films ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Glass Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Air Water Interface

AbstractA soluble, asymmetrically substituted polydiacetylene, poly(BPOD), has been reported to form stable monolayers at the air-water interface by the Langmuir-Blodgett (LB) technique [2]. Preformed polydiacetylene has been deposited onto hydrophobic substrates as multilayers to form second order nonlinear optical thin films. Second harmonic generation was found to increase with the number of layers. From previous atomic force microscopy (AFM) studies backbone orientation along the dipping direction with an interchain spacing of about 5 A° was indicated [2].The film morphology and preferential molecular orientation of these LB films are further investigated by transmission electron microscopy (TEM). A specifically tailored sample preparation method for the ultrathin LB films was used. Multilayer films were deposited on hydrophobic collodion covered glass substrates for this purpose. Electron diffraction was employed to study the crystalline organization of mono and multilayers of LB films as well as cast films.

New Strategies for Preparing Electrically Conductive Langmuir-Blodgett Films

1992 ◽  
Vol 247 ◽  
Author(s):  
J. H. Cheung ◽  
R. B. Rosner ◽  
M. F. Rubner
Keyword(s):  
Electrical Properties ◽  
Stearic Acid ◽  
Structural Changes ◽  
Solid State Reactions ◽  
Emeraldine Base ◽  
Structure Property ◽  
Electrically Conductive ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films

ABSTRACTThe fabrication, structure and electrical properties of new electrically conductive Langmuir-Blodgett (LB) films of polyaniline and polypyrrole have been investigated. Polyaniline in its emeraldine-base form was mixed with stearic acid (PAN-B/SA) to produce stable films at the air-water interface (5/1 or 10/1 mole ratio of PAN-B/SA). These films were then transferred into multilayer films which were found to exhibit conductivities of about 1 S/cm upon doping with hydrochloric acid. The alkyl chains of the stearic acid molecules were found to be distributed randomly throughout the LB film thereby exerting a minimal influence on the electrical properties of the polyaniline phase. In addition to this mixed monolayer approach, a novel method of fabricating highly conductive polypyrrole LB films has been developed. This method is based on the sequential exposure of ferric stéarate LB films to hydrogen chloride (HC1) gas and pyrrole vapor. Each of these two solid state reactions was found to impart dramatic chemical and structural changes to the film. Polypyrrole LB films with conductivities as high as 5 S/cm were produced via this process. The electrical and optical properties of films made by both techniques were examined in order to elucidate their structure/property relationships.

scholarly journals Monolayer Behavior of Cyclic and Linear Forms of Surfactins: Thermodynamic Analysis of Langmuir Monolayers and AFM Study of Langmuir-Blodgett Monolayers

2014 ◽  
Vol 63 (4) ◽  
pp. 407-412 ◽  
Author(s):  
Toshiaki Taira ◽  
Shintaro Ikeda ◽  
Daisuke Kawamura ◽  
Hideki Sakai ◽  
Masahiko Abe ◽  
...  
Keyword(s):  
Thermodynamic Analysis ◽  
Langmuir Monolayers ◽  
Linear Forms ◽  
Langmuir Blodgett
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