Polyatomic Adsorbates on Carbon Nanotube BundlesAldo D. Migone, Southern Illinois University Carbondale, DMR 0705077

This project combines experimental and theoretical methods to explore the adsorption of molecules of various shapes and lengths on carbon nanotube bundles.

New phases of matter, phase transitions and distinctive dynamical behavior are expected as a consequence of both, the polyatomic nature of the adsorbates and the unique geometry of the nanotube bundles. Our results will help to bring the adsorption applications that have been suggested for this nanostructure (gas separation, enviromental remediation and storage) closer to implementation.

Simulating adsorption kinetics of dimers. Blue line: Amount of dimers standing up as a function of time; red line: same for dimers that lie flat on the surface.

Some of our recent results:

Experimental adsorption isotherms of carbon chains of increasing length (alkanes) show clear evidence of a “size entropy effect” as longer molecules cannot be packed as efficiently as shorter ones.

A decrease in the specific surface area with the length of the molecule is explained by a model developed by our theory partners in Argentina that takes into account the vacant sites left uncovered as the chain length increases (D. S. Rawat et al., Langmuir 25, 9227, 2009).

Simulations of the way diatomic molecules become adsorbed on this structure (done by the theory group of the Co-PI at SIUC) show that dimers tend to lie flat on the surface at early stages of the equilibration but they would stand up when the system approaches equilibrium if the chemical potential is relatively high.

A unique educational aspect of this project comes from the exchanges of students and researchers between Southern Illinois University and the Universidad Nacional San Luis (Argentina) that form part of the proposed research plan. The research conducted at both institutions benefits from the training of young researchers and from strengthening the existing partnership.

Prof. Migone talks with Giorgio Zgrablich, founder of the Lab of Porous Media at the National University of San Luis – Argentina.

Polyatomic Adsorbates on Carbon Nanotube BundlesAldo D. Migone, Southern Illinois University Carbondale, DMR-0705077

The theory groupat SIUC

Diversity is Power!

Nayeli Zuniga

Mercedes CalbiSeyoum Tsige

Jared Burde