Surface tension, a thermodynamic function, is the reversible work required to create incremental interface between two phases, energy per unit area of interface. The surface tension changes when the interface is curved, e.g., the equilibrium vapor pressure between a liquid and its vapor, for a liquid confined in a capillary, differs from a flat interface. If the interface is between a solid catalyst and a reacting fluid (heterogeneous catalysis), the catalytic activity and selectivity can be changed by varying the radius of curvature of the interface, e.g., by varying the pore diameter of the solid in which the fluid reacts, see J. Catal., (2005), 234(2), 318-327. This interfacial phenomena can also be used to control growth rate and size of metal particles, see J. Phys. Chem. B (2005), 109(6), 2285-2294, which in turn can be used to control the diameter of single walled carbon nanotubes (SWNT), whose diameter is approximately that of the metal particle on which it grows, see J. of Phys. Chem. B (2004), 108(2), 503-507. The synthesis, characterization and study of the mechanism of catalysis of SWNT is an active area of research in Chemical Engineering at Yale.
Single walled carbon nanotubes have a variety of applications, many of which are controlled by the interface between the SWNT and the second phase. The activity of proteins adsorbed at the SWNT/water interface modifies their chemistry and activity, see Nano Letters (2008), 8(7), 2070-2076. Single walled carbon nanotubes have a direct application in the design of catalyst as supports for catalytic carbide, oxide and metal active components. Such supports have unique properties such as water insolubility (for aqueous reforming catalysts for hydrogen production from renewable resources) and solubility in organics facilitating the development of fuel soluble combustion catalysts for aviation or other high performance fuels. Several catalyst for applications are under investigation by the Yale Chemical Engineering faculty.