Special Issues-08-01-2012

The beginning of the age of Fourier transform infrared (FT-IR) spectroscopy meant the availability of digital spectra and opened the possibility of using computers to compare a single spectrum against a reference database containing thousands of spectra, thereby allowing enormous efficiency gains in the comparison of unknown spectra to reference materials. Various algorithms can be used to create a hit quality index (HQI), which is a measure of how well the query spectrum compares against each reference spectrum.

Infrared reflection spectroscopy is a tool that can be used to study coated plastics, but the spectra can show unexpected features. In this report, we calculate the specular reflectance for a flat surface of two different polymers as well as how their spectra change when the other polymer is added as a film with a thickness of up to 2.5 ?m. One of the unusual phenomena we observe is that "derivative"-shaped substrate bands invert in sign as the other polymer is added as a coating. We also show how the reflection of the surface changes and becomes polarized as the angle of incidence increases.

Special Issues

Self-assembled monolayers (SAMs) can be applied in a variety of technical areas. Infrared characterization of these materials is a challenge because of the low concentrations on the surfaces. This article reviews the sampling methods for characterization and presents data comparing the different approaches.

The micro attenuated total reflectance (ATR) chemical imaging of polymers, in particular polymer laminates, typically requires significant pressure to ensure good sample-to-ATR crystal contact. For thin cross-sectioned materials, ensuring structural rigidity against this pressure requires significant sample preparation, such as resin embedding, cutting, and polishing.

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Special Issues

August 01, 2012

Click the title above to open the Spectroscopy August 2012 regular issue, Vol 27 No 8, in an interactive PDF format.