An atomic force microscopy study of weathering of polyester/melamine paint surfaces

The use of an atomic force microscope (AFM) for rapid assessment of the durability of exterior polyester/melamine paints has been investigated. The study established an AFM imaging technique that produces data representative of weathering rates of paint films under a range of weathering regimes of varying severity. The effect of scan size on the average roughness parameter was investigated, leading to the adoption of two specified scan sizes. It was further found that both TappingMode(TM) and contact mode imaging gave equivalent detail of surface topography for these samples. However, TappingMode(TM) gave a clearer representation of the pigment/binder composite structure. Importantly, a technique was developed which reduces sample to sample variability by allowing a specified area to be repeatedly imaged as a function of weathering time. The images collected were found to show important detail regarding the mechanism of weathering, and the role of binder stability and pigment loss. (C) 2001 Elsevier Science B.V. All rights reserved.