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Nanoscale Characterization of Coatings Surface Degradation With Tapping Atomic Force Microscopy.


pdf icon Nanoscale Characterization of Coatings Surface Degradation With Tapping Atomic Force Microscopy. (913 K)
Nguyen, T.; Gu, X.; VanLandingham, M.; Ryntz, R.; Nugyen, D.; Martin, J. W.

Adhesion Fundamentals: From Molecules to Mechanisms and Modeling. Adhesion Society Annual Meeting, 26th. Proceedings. February 23-26, 2003, Myrtle Beach, SC, 508-510 pp, 2003.

Keywords:

coatings; microscopy; degradation; atomic force microscopy; chemical heterogeneity; relative humidity; humidity; phase contrast; friction contrast

Abstract:

Surface characteristics of a polymer coating, such as gloss, and their changes with weathering depend strongly on surface topography and morphology. Therefore, data on early physical changes of coatings surface can provide valuable information for not only understanding the degradation mode but also for predicting long term performance. Atomic force microscopy (AFM) is well suited for studies of early coatings degradation, as demonstrated recently. This paper presents examples from the research in our laboratory on the use of both the phase and topographic imaging in tapping mode AFM (TMAFM) to investigate early surface physical degradation of coatings exposed to weathering environments. In tapping mode AFM, the probe is oscillated at a frequency near resonance. As the tip approaches the sample, the tip-sample interactions change the amplitude, resonance frequency, and phase angle of the oscillating probe. Detection of the amplitude and phase changes during scanning provides the topographic and phase images, respectively. Phase imaging in TMAFM is sensitive to both mechanical and chemical properties of the surface and tip-sample interactions.