Proceedings of SCANNING 2000 May 9–12, 2000 San Antonio, Texas, USA

Abstract

The layer sequence of multilayered white and off-white paint chips is sometimes difficult to discern when utilizing commonly employed microscopical methods. This layer sequence information becomes vitally important when comparing a questioned paint sample to a paint sample of known origin. Techniques such as reflected light microscopy, fluorescence microscopy, and scanning electron microscopy (SEM) coupled with energy dispersive x-ray spectrometry (EDS) may not provide the needed discrimination. The elemental information obtained by EDS is of limited value since elemental composition alone is not sufficient to identify pigments/extenders used in white and offwhite paints or to distinguish between different phases. Also, binder information may not be available for comparison since the thinness of the layers and the abundance of extender pigments may preclude analysis by Fourier transform infrared (FTIR) microspectrophotometry.Cathodoluminescence microscopy (CLM) may provide the needed layer sequence information and discrimination when analyzing and comparing multilayered white and off-white paint samples. Cathodoluminescence is the emission of radiation from the sample in the visible light region and neighboring wavelengths following excitation by electrons generated from a cathode electron gun. CLM provides further discrimination of the layer sequence of multilayered white and off-white paint samples since cathodoluminescence is sensitive to phase differences, trace amounts of foreign atoms, and other lattice imperfections.Analysis of polished cross-sections by CLM was accomplished utilizing a light microscope coupled with a vacuum specimen chamber and a cold-cathode electron gun. A comparison was made of the layer information obtained by CLM, darkfield reflected light microscopy, fluorescence microscopy, and SEM-EDS of several architectural paint cross-sections.

Observation of Continuous and Quantized Domain Size and Shape Evolution in Monolayers at Air–Water Interface

“…The reflected light is collected by an infinity-corrected optical system, composed of a 10Â objective and a tube lens, whose resolution is 0.84 m. The collected light is detected by a charge-coupled device (CCD) camera and BAM images are analyzed by the Lispix software. 31)…”