On the Use of the Atomic Force Microscope to Monitor Physical Degradation of Polymeric Coating Surfaces

Published

December 1, 2001

Author(s)

Mark R. VanLandingham, Tinh Nguyen, Walter E. Byrd, Jonathan W. Martin

Abstract

The atomic force microscope (AFM) was used to monitor changes in surface features of an acrylic melamine polymeric coating that was exposed to a variety of weathering conditions. A technique was developed such that, upon periodic removal from the weathering environment, the same 100 mm x 100 mm regions were scanned for each sample. Exposure to ultraviolet (UV) radiation and high relative humidity caused general roughening of the surface and the formation of pits. Further, the damage of the coating surface was much more substantial for exposure to high relative humidity compared to exposure to dry environments. A mechanism for the formation of pits in the surface is postulated based on measurements of chemical degradation determined using infrared spectra that were acquired synchronously along with the AFM images. Although this coating is a model system, its commercial counterpart is known to experience catastrophic failure in service through the formation of microcracks. A mechanism for such catastrophic failure is presented based on the observed pitting phenomenon combined with expected changes in the physical properties of the polymer.

Citation

JCT, Journal of Coatings Technology

Volume

73

Issue

No. 923

Pub Type

Journals

Keywords

atomic force microscopy, chemical degradation, environmental exposure, Fourier transform infrared (FTIR) spectr, physical degradation, polymer materials, relative humidity, service life prediction, ultraviolet (UV) radiation

Citation

VanLandingham, M. , Nguyen, T. , Byrd, W. and Martin, J. (2001), On the Use of the Atomic Force Microscope to Monitor Physical Degradation of Polymeric Coating Surfaces, JCT, Journal of Coatings Technology (Accessed February 16, 2025)