Background and the method:

TEM is a primary technique for mrasuring exfoliation and dispersion of nanoparticles in nanocomposites. The method cannot be readilly adoptable for manufacturing of nanocomposites because of limited area of visualization. A new and simple method based on air plasma etching and SEM imaging is developed.

Approach and Results:

Plasma etching is a chemical process where RF discharge on a parent gas generates reactive species when these species strike a substrate in vaccum they erode the surface. When a polymer based nanocomposite is exposewd to air plasma, the oxygen ions oxidizes the polymer parts of the sample exposing the inorganic nanoparticles. Oxidation rate is in nanometers per minute thus enabling etch to different depths to visualize the exfoliation and dispersion of the nanoplatelets through scanning electron microscope (SEM). Figure on right shows a schematic of plasma etching system and SEM images of the nanoclay/vinyl ester nanocomposite etched samples. The figure reveals surface, edges and obligue orientatiojn of clay platelets. Etch rate for these samples ranged from 2 to 8 nm/minute depending on power and etch duration.

Conclusions:

The technique is promising for quick screening of exfoliation and dispersion of nanocomposites in a manufacturing and/or materials development environment.