A Faster Approach to Infrared Rheo-Optics Using a Planar Array Infrared Spectrograph

Abstract

Infrared rheo-optics combines dynamic mechanical analysis with infrared spectroscopy to provide molecular level information about the segmental reorientation and the changes in local environment associated with the dynamic deformation of polymers. Up to now, the application of this technique has been limited by the amount of time necessary to perform the experiments. In this article, we demonstrate that the use of a planar array infrared (PA-IR) spectrograph can accelerate the acquisition time by as much as two orders of magnitude while maintaining a signal-to-noise ratio (SNR) similar to that obtained using step-scan Fourier transform infrared (FT-IR) spectrometry, and by more than three orders of magnitude at the expense of a reduced SNR. The advantages and drawbacks of this new technique are discussed.

Concerning the spectral resolution enhancement of dynamic 2D-IR

“…In order to significantly increase the SNR, it is necessary to develop new interferometers with higher optical efficiency, optical throughput, detector sensitivity or smaller detector area. For this purpose, a planar array infrared spectrograph (PA-IR) [41] is quite promising, which can accelerate the acquisition time by as much as two orders of magnitude while maintaining a SNR similar to that obtained using step-scan FT-IR. The drawbacks of PA-IR as compared to FT-IR, however, are the reduction of spectral range, resolution, and frequency accuracy.…”

Dynamic Infrared Study of Polyphenylene Sulfide Using Planar Array Infrared Spectroscopy

“…This has advantages in systems where the sample perturbation itself changes the chemical or physical structure of the sample, or where the study of irreversible processes is desirable. The ability of PA-IR spectroscopy to perform rheo-optical experiments was demonstrated in a previous paper, 7 where in-phase and quadrature spectra were acquired from a single strain cycle lasting 70 ms. The sensitivity of the PA-IR technique, together with its robustness and simplicity, allow this setup to acquire dynamic infrared spectra of the same quality but in a much shorter time compared to FT-IR.…”

Rapid Molecular Imaging Using Attenuated Total Internal Reflection Planar Array Infrared Spectroscopy for the Analysis of Counterfeit Pharmaceutical Tablets

“…PA-IR spectroscopy is gaining acceptance as a viable alternative to FT-IR spectroscopy for many applications. [20][21][22][23][24][25][26][27][28] The emergence of PA-IR spectroscopy can be attributed to its sensitivity, rugged nature (no moving parts), and multichannel detection capabilities for imaging. Most of the current PA-IR systems incorporate either grating or prism-based macro sampling accessories and employ mercury cadmium telluride (MCT) focal plane array detectors.…”