- Author
-
Raghavan, D.
|
Gu, X.
|
Nguyen, T.
|
VanLandingham, M. R.
- Title
- Characterization of Chemical Heterogeneity in Polymer Systems Using Hydrolysis and Tapping-Mode Atomic Force Microscopy.
- Coporate
- Howard Univ., Washington, DC
National Institute of Standards and Technology, Gaithersburg, MD
- Journal
-
Journal of Polymer Science: Part B, Polymer Physics,
Vol. 39,
No. 13,
1460-1470,
2001
- Keywords
-
atomic force microscopy
|
microscopy
|
chemical modification
|
coatings
|
hydrolysis
|
heterogeneity
|
phase imaging
|
polymers
- Abstract
- Characterization of polymer coatings microstructure is critical to the fundamental understanding of corrosion of coated metals. An approach for mapping chemical heterogeneity of a polymer system using chemical modification and tapping mode atomic force microscopy (TMAFM). This approach is based on selective hydrolysis of one of the phases in a multiphase polymer blend system and the ability of TMAFM to provide nanoscale lateral information about the different phases in the polymer system. Films made of 70:30 polyethyl acrylate/polystyrene (PEA/PS) blend were exposed to a hydrolytic acidic environment and analyzed using TMAFM. Pits were observed to form in the PEA/PS blend films and this degradation behavior was similar to that of the PEA material. Using these results, the domains in 70:30 blend were identified as the PS-rich regions and the matrix as the PEA-rich region. This conclusion is confirmed by Fourier transform infrared-attenuated total reflection analyses that revealed the hydrolysis of the PEA material. TMAFM phase imaging was also used to follow pit growth of the blend as a function of exposure time. The usefulness of the chemical modification/AFM imaging approach in understanding the degradation process of a coating film is discussed.