Infrared Photoacoustic Spectroscopy of Conducting Polymers. I. Undoped and n-Doped Polyacetylene

1981 ◽  
Vol 35 (6) ◽  
pp. 557-559 ◽  
Author(s):  
Stephen M. Riseman ◽  
Stuart I. Yaniger ◽  
Edward M. Eyring ◽  
David Macinnes ◽  
Alan Graham Macdiarmid ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectrum ◽  
Conducting Polymers ◽  
Infrared Spectra ◽  
Photoacoustic Spectroscopy ◽  
Fourier Transform Infrared ◽  
Spectral Shifts ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

Fourier transform infrared photoacoustic (FT-IR-PA) spectroscopy has been used to obtain the first published infrared spectrum of a heavily n-doped polyacetylene. Comparisons are made with the FT-IR-PA spectrum of undoped polyacetylene. All the infrared peaks in the FT-IR-PA spectrum of undoped polyacetylene agree in wavelength to ±10 cm−1 with transmission infrared peaks previously assigned by Shirakawa and Ikeda. Spectral shifts and intensity differences between the n-doped and undoped polyacetylene are similar to changes noted previously in the infrared spectra of p-doped polyacetylenes.

Infrared Photoacoustic Spectroscopy of Conducting Polymers III. Polyparaphenylene and its Derivatives

1984 ◽  
Vol 38 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Stuart I. Y. Aniger ◽  
David J. Rose ◽  
William P. McKenna ◽  
Edward M. Eyring
Keyword(s):  
Fourier Transform ◽  
Conducting Polymers ◽  
Organic Semiconductor ◽  
Photoacoustic Spectroscopy ◽  
Fourier Transform Infrared ◽  
High Quality ◽  
Organometallic Derivative ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

Fourier Transform Infrared Photoacoustic (FT-IR/PA) spectroscopy provides a means to obtain high quality spectra of polyparaphenylene (PPP), an organic semiconductor. Spectra of PPP prepared by two different methods, heavily n-doped PPP, and a new organometallic derivative, PPP(Mo(CO)3)0.25 are presented. Spectral acquisition times for these polymers can be as low as one minute.

Depth Profile Study of Large-Sized Coal Samples by Fourier Transform Infrared Photoacoustic Spectroscopy

1986 ◽  
Vol 40 (2) ◽  
pp. 214-217 ◽  
Author(s):  
Tiziana Zerlia
Keyword(s):  
Fourier Transform ◽  
Depth Profile ◽  
Photoacoustic Spectroscopy ◽  
Modulation Frequency ◽  
Fourier Transform Infrared ◽  
Qualitative Description ◽  
Difference Spectra ◽  
Compositional Depth Profile ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

A multidisciplinary approach is demonstrated to elucidate coal weathering at a molecular level. Fourier Transform Infrared Photoacoustic Spectroscopy (FT-IR/PAS) provides a technique for a compositional depth profile of coal by simply varying the modulation frequency (mirror velocity) of the light impinging upon the solid surface. In order that the potential of this technique in this field could be evaluated, large-sized coal samples were examined. The PA difference spectra obtained from the spectra taken at different modulation frequencies (i.e., different depths), on a sample aged in air, demonstrate the appearance of negative features in the CH infrared absorption which are indicative of a coal alteration. Therefore, different coal layers can be distinguished by FT-IR/PAS. The application of the same technique to the study of a coal sample heated in air at 200°C allows the detection of different oxidation mechanisms operating inside and outside the coal. Although quantitative results are difficult to obtain, the technique can be successfully proposed for a qualitative description of coal weathering.

Analysis of Cheese Using Step-Scan Fourier Transform Infrared Photoacoustic Spectroscopy

2000 ◽  
Vol 54 (4) ◽  
pp. 595-600 ◽  
Author(s):  
Joseph Irudayaraj ◽  
Hong Yang
Keyword(s):  
Signal Processing ◽  
Fourier Transform ◽  
Photoacoustic Spectroscopy ◽  
Depth Profiling ◽  
Cheddar Cheese ◽  
Digital Signal ◽  
Fourier Transform Infrared ◽  
Intact Sample ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

The potential of Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) for examination of food and the package was demonstrated. Full-fat cheddar cheese slices wrapped in polymer package were chosen as the food sample for analysis. Photoacoustic spectroscopy (PAS) in conjunction with the step-scan and digital signal processing (DSP) function was used to perform depth-profiling studies of the intact sample and package. Well-separated PAS bands of fat and protein were obtained in the spectra of cheddar cheese samples with minimum sample preparation. Cheese samples were kept in a dessicator overnight to minimize the effect of moisture on the PAS spectra. Depth profiling study of the cheese polymer package indicated that there is a diffusion of cheese components into the package during storage.

Fourier Transform Infrared Photoacoustic Spectroscopy Characterization of Sulfur-Oxygen Species Resulting from the Reaction of SO2 with CaO and CaCO3

1987 ◽  
Vol 41 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Meg A. Martin ◽  
Jeffrey W. Childers ◽  
Richard A. Palmer
Keyword(s):  
Fourier Transform ◽  
Photoacoustic Spectroscopy ◽  
Depth Profiling ◽  
Fourier Transform Infrared ◽  
Product Layer ◽  
Oxygen Species ◽  
Initial Product ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) has been used to investigate the reaction of SO2, in He with CaO and CaCO3 particles at temperatures between 25 and 900°C. The reaction of SO2 with CaO occurs at 25°C, while the reaction of CaCO3 with SO2 is first evident at 550°C. The initial product of both of these reactions is CaSO3. The CaSO3 then further reacts with SO2 to form CaSO4, CaS2O3, and CaS at higher temperatures. At 900°C and above, the net production of SO4= and S2O3= is decreased because of the decomposition of SO3=. FT-IR/PAS depth-profiling experiments indicate the formation of a reaction-limiting product layer of SO3= and SO4= from the above reactions on the surface of the CaO and CaCO3 particles.

Quantitative Determination of Catalytic Surface Adsorption Sites by Fourier Transform Infrared Photoacoustic Spectroscopy

1983 ◽  
Vol 37 (2) ◽  
pp. 131-133 ◽  
Author(s):  
Joseph A. Gardella ◽  
Da-Zhen Jiang ◽  
Edward M. Eyring
Keyword(s):  
Fourier Transform ◽  
Quantitative Analysis ◽  
Calibration Curve ◽  
Photoacoustic Spectroscopy ◽  
Surface Adsorption ◽  
Fourier Transform Infrared ◽  
Catalytic Surface ◽  
Adsorption Sites ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

The use of Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) as a method for quantitative analysis of surface adsorption sites is demonstrated. Mid-IR information about the amount of adsorption is available with the sampling advantages of PAS: ability to analyze opaque materials with minimal sample preparation, qualitative information about both gas [CO(g)] phase and adsorbed [CO(ads)] species, a sealed sample environment for control of the gas phase in contact with the sample, and the ability to monitor in situ reaction kinetics. In this study a calibration curve is constructed for the amount of CO(g) in the sample cell with a silica internal reference. This calibration curve is utilized to calculate the amount of CO(ads) by subtraction on a catalytic surface where both CO(g) and CO(ads) exist at equilibrium. Using standard parameters from gas titration/volume uptake studies, the surface covered and the percentage of active sites on the surface are determined. This analysis combines the qualitative analytical capabilities of PAS with quantitative analysis, thus demonstrating another facet of the usefulness of FT-IR/PAS in addressing unusual problems.

Determination of the Orientation of Silanes on Silica Surfaces by Fourier Transform Infrared Photoacoustic Spectroscopy

1986 ◽  
Vol 40 (4) ◽  
pp. 513-519 ◽  
Author(s):  
Marek W. Urban ◽  
Jack L. Koenig
Keyword(s):  
Fourier Transform ◽  
Photoacoustic Spectroscopy ◽  
Surface Coverage ◽  
Silica Surface ◽  
Fourier Transform Infrared ◽  
Coupling Agents ◽  
Surface Hydroxyl ◽  
Silica Surfaces ◽  
Quantitative Surface Analysis ◽  
Infrared Photoacoustic Spectroscopy

Fourier transform infrared photoacoustic spectroscopy has been used for quantitative surface analysis of silica treated with trifunctional coupling agents such as γ-Methacryloxypropyltriethoxysilane (γ-MPS), γ-Glycidoxypropyltrimethoxysilane (γ-GPS), and γ-Aminopropyltri-ethoxysilane (γ-APS). The calibration curves are obtained for several characteristic bands of the coupling agents. Using a highly polarizable gas in the photoacoustic cell and comparing the spectra with a nonpolarizable coupling gas, it is possible to evaluate orientation of the coupling agents on the silica surface. The type of orientation is a function of the extent of surface coverage. At low surface coverage, coupling agents tend to take a perpendicular orientation with respect to the surface, and increasing surface coverage leads to parallel orientation. Increasing the coupling agent concentration also causes orientational changes of the species which form chemical bonds with the silica surface (hydroxyl, water, and carbonyl groups).

Gas Chromatographic/Matrix Isolation/Fourier Transform Infrared Spectra of the Laterally Chlorinated Dibenzo-p-Dioxins and Dibenzofurans

1989 ◽  
Vol 43 (8) ◽  
pp. 1317-1324 ◽  
Author(s):  
Charles J. Wurrey ◽  
Billy J. Fairless ◽  
Harry E. Kimball
Keyword(s):  
Fourier Transform ◽  
Infrared Spectra ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Fourier Transform Infrared Spectra ◽  
Reference Quality ◽  
Ft Ir ◽  
Chlorinated Dioxins ◽  
Chromatographic Matrix ◽  
Ft Ir Spectroscopy

Reference-quality gas chromatographic/matrix isolation/Fourier transform infrared spectra have been recorded for the following fifteen compounds, which collectively are referred to as the “laterally” chlorinated dibenzo- p-dioxins and dibenzofurans: 2,3,7,8-tetrachlorodibenzo- p-dioxin (2,3,7,8-TCDD); 1,2,3,7,8-pentachlorodibenzo- p-dioxin (1,2,3,7,8-PeCDD);l,2,3,4,7,8-hexachlorodibenzo- p-dioxin(1,2,3,4,7,8-HxCDD)>; 1,2,3,6,7,8,-hexachlorodibenzo- p-dioxin(1,2,3,6,7,8-HxCDD); 1,2,3,7,8,9-hexachlorodibenzo- p-dioxin (1,2,3,7,8,9-HxCDD); 1,2,3,4,6,7,8-heptachlorodibenzo- p-dioxin (1,2,3,4,6,7,8-HpCDD); 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF); 1,2,3,7,8-pentachlorodibenzofuran (1,2,3,7,8-PeCDF); 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF); 1,2,3,4,7,8-hexachlorodibenzofuran(1,2,3,4,7,8-HxCDF); 1,2,3,6,7,8-hexachlorodibenzofuran (1,2,3,6,7,8-HxCDF); 1,2,3,7,8,9-hexachlorodibenzofuran (1,2,3,7,8,9-HxCDF); 2,3,4,6,7,8-hexachlorodibenzofuran (2,3,4,6,7,8-HxCDF); 1,2,3,4,6,7,8-heptachlorodibenzofnran (1,2,3,4,6,7,8-HpCDF); and 1,2,3,4,7,8,9-heptachlorodibenzofuran (1,2,3,4,7,8,9-HpCDF). These spectra are discussed qualitatively and, for the laterally chlorinated dioxins, are compared to previously recorded gas-phase GC/FT-IR spectra. Estimates of the instrumental detection limits for these compounds, using matrix isolation GC/FT-IR spectroscopy, were found to fall in the mid-to-high picogram and low nanogram ranges.

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