The surface area per gram of a rod is inversely proportional to the radius of the rod. With the development of single walled carbon nanotubes (SWNTs), the large surface area (1200 m2/g) has been both a curse and a blessing. The attraction between individual SWNTs combined with the surface area has driven aggregation, which reduces the effectiveness of the nanotubes in polymer nanocomposites. However, as the scientific community has explored very low concentrations and developed methods of dispersing the nanotubes, better than expected results (mechanical and thermal) have been demonstrated.

The positive results originate from the interaction between the SWNTs and the polymer matrix. The polymer near the surface of the SWNT has slower kinetics and higher elastic modulus; this region of the matrix is called the interphase. The interphase is important not only because it allows us to create polymer nanocomposites with enhanced properties, but to explore polymer physics as well.

This poster will highlight my graduate work on exceptional modulus changes at ultra low concentrations of single walled carbon nanotubes. In this work, we demonstrated that attractive interactions between the nanotube and polymer system, as demonstrated by Raman spectroscopy, combined with dispersed nanotubes at concentrations below 0.35 wt. % led to higher than volume additive enhancements of the storage modulus. The results were demonstrated with pristine SWNTs and PMMA as well as functionalized SWNTs with polystyrene.

In addition, my current postdoctoral work on the effect of nanoparticle shape on the creation and properties of the interphase will be highlighted. In this work, nanoparticles of different dimensionality (0D, 1D, 2D) with the same surface modifications are used to investigate how the shape of the interface changes the properties of the interphase. The results are discussed in light of polymer physics and a method to new model the properties of the interphase is presented.