Fourier transform infrared photoacoustic spectroscopy of polymeric laminates

Abstract

Photoacoustic Fourier transform infrared spectroscopy of nanoporous SiO x ∕ Si thin films with varying porosities J. Appl. Phys. 98, 114310 (2005); 10.1063/1.2138376 X-ray photoemission spectroscopy and Fourier transform infrared studies of dye molecule doped conducting polymer films J. Vac. Sci. Technol. A 23, 869 (2005); 10.1116/1.1914816The (n00), n=3, 4, and 6, local mode states of H 3 SiD : Fourier transform infrared and laser photoacoustic spectra and ab initio calculations of spectroscopic parameters Photoacoustic ͑PA͒ magnitude and phase spectra of, respectively, polyethyleneterephthalate/ polyethyleneterephthalate ͑PET/PET͒, polypropylene/polyethyleneterephthalate ͑PP/PET͒, and polyethyleneterephthalate/polypropylene ͑PET/PP͒ laminates are presented. The extension of the Rosencwaig-Gersho theory to a double-layered system introduced by N. C. Fernelius ͓J. Opt. Soc. Am. 70, 480 ͑1980͒ and J. Appl. Phys. 51, 650 ͑1980͔͒ is applied to compare the experimental data with simulated PA magnitudes and phases. The simulations for the double-layered systems indicate that the absorption coefficient ␤ at the optically transparent region of the single layers-estimated from photoacoustic data-strongly influences the phase spectra of the polymeric laminate. In particular, the relative magnitude of these residual absorptions in the two layers is important. The optical absorption spectra of the polypropylene and polyethyleneterephthalate single layers ͑accessible from infrared absorbance and infrared photoacoustic spectra͒ were used to simulate the photoacoustic magnitude and phase spectra of the two possible double layers, i.e., PP/PET and PET/PP. A reasonable agreement of experimental and simulated photoacoustic data is observed.

Depth Profiles in Coated Paper: Experimental and Simulated FT-IR Photoacoustic Difference Magnitude Spectra

“…One should therefore take into account the in¯uence of a variable absorption coef® cient b for the same IR band in multi-layers on the PA m agnitude and phase, if IR-PA spectra of unknown laminates are studied. These results again illustrate 17 that the photoacoustic signal generation in chemically heterogeneous laminates cannot be separated into individual processes for each individual single layer. The thermal heat¯ows are interdependent due to the boundar y conditions.…”

“…16 Recently, we presented simulated and experimental PA phases and m agnitudes of polym eric double layers. 17 The full solution (i.e., Fernelius' expression) describing the photoacoustic effect was applied to com pare experimental PA m agnitudes and phases to simulated data. It turned out that only the use of the full description of the PA effect provides a clear understanding of especially the PA phase data of polym eric double layers.…”

Analysis of Botulinum Neurotoxin Detection by Mass Spectrometry in Forensic Samples

“…A variety of analytical techniques, including use of UVvisible microspectrophotometry [18], Fourier transform infrared spectroscopy (FTIR) with total attenuated reflectance (ATR) [19], Surface-enhanced Raman spectroscopy (SERS) [20], scanning electron microscopy with energy dispersed X-ray spectrometry (SEM-EDS) [21], inductively coupled plasma optical emission spectrometry (ICP-OES) [22], atomic absorption spectroscopy (AAS) [23], scanning electrochemical microscopy (SECM) [24], atomic force microscopy (AFM) [25], confocal laser scanning microscopy (CLSM) [26], gas chromatography with mass spectrometry (GCMS) [27] capillary electrophoresis [28] (CE) , and laser inducedbreakdown spectroscopy (LIBS) [29], have been used to provide fundamental knowledge and insightful information for forensic cases. Photoacoustic spectroscopy is also used for quantitative and qualitative analysis of explosives, ink, paints, pigments and tissues [30][31][32][33][34][35][36].…”

Quantitative Depth Profiling Using Saturation-Equalized Photoacoustic Spectra

“…24,26 Phase modulation has resulted in increased research on using PAS for depth pro ling. 23,24,[26][27][28][29][30][31][32][33] Nevertheless, conventional depth pro ling by frequency variation remains the more popular approach, both because of the higher cost of phase-m odulation spectrometers and because of the m ore complicated data processing and interpretation of phase data.…”