Characterization of Thin Films and Layered Structures by Pulsed Photothermal Radiometry
Pulsed photothermal radiometry (PPTR) relies on the use of a short optical pulse to quickly heat up a sample, and the detection of the transient thermal radiation from the sample surface. Similar to pulsed photoacoustic sensing techniques1, PPTR has applications in spectroscopy, coating thickness measurment and powder aggregation detection2, thin-film thickness or thermal diffusivity measurements3, pigment characterization4 and fiber composite strength characterization5. This paper examines how the PPTR signal shape can be analysed to determine quantitatively the thickness of subsurface airgaps in layered structures. Furthermore, we demonstrate the effect of moisture uptake in polymer films on the PPTR signal.
KeywordsMoisture Uptake Ambient Relative Humidity Thermal Diffusivity Measurements3 Backing Material Ribbon Thickness
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