Adsorption is a process by which molecules of a gas or liquid are attracted to the surfaces of a solid (or liquid), and stick to them forming films. This phenomenon is naturally present in most physical, biological, and chemical systems, and has been widely used in industrial applications (e.g., the purification of fluids, or the removal of toxic ingredients from a gas stream). Porous materials, such as carbon nanotube bundles, are especially well suited for studying adsorption because they offer large, accessible, areas to the adsorbing species. The adsorption of spherical molecules on carbon nanotubes has been extensively investigated during the last decade. Most of the technological applications suggested for adsorption, on the other hand, involve molecules of various shapes and lengths. The information obtained by combining theoretical and experimental methods in the exploration of films of non-spherical (linear and quasi-linear) molecules will provide the basic knowledge needed to bring the applications that have been suggested closer to implementation. Participation of students in this project will provide them with a unique exposure to complementary experimental and computational methods, and will allow their involvement in a research experience abroad, as a result of the international component of this project.
This experimental-theoretical collaboration aims to explore the behavior of different linear and quasi-linear molecules physisorbed on the surfaces of carbon nanotubes. New phases of matter and phase transitions, as well as distinctive dynamical behavior are expected to arise as a consequence of both, the polyatomic nature of the adsorbates and the unique geometry of the nanotube bundles. Adsorption isotherms measurements combined with computer simulations and theoretical modeling will be used to obtain a comprehensive description of the phenomena that occur in these systems. Particular emphasis will be placed on determining the effect of the size and shape of the adsorbates on the behavior of the films as well as on their adsorption/desorption kinetics and molecular diffusion. This project will help develop some of the basic knowledge needed to enable potential applications of adsorption on nanotubes to processes such as gas purification, separation, and storage. A unique educational aspect of this project are the planned exchanges of students and researchers between Southern Illinois University and the Universidad Nacional San Luis (Argentina). The opportunity of conducting research at both institutions will benefit the young researchers being trained through this project. The exchanges will also strengthen the existing research partnership.
