TITLE: "Slip, Slide, and Roll -- Nanotube tribology"

SPEAKER: Professor Richard Superfine,

TIME: Thursday, January 14, 1999, starting at 4:00 PM

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

What can you learn from touching molecular structures? We have pursued the study of nanometer-scale materials, including colloids, viruses, DNA and nanotubes, through the use and development of an advanced interface for scanning probe microscopy (SPM). The ability to manipulate objects efficiently on surfaces makes available a wide variety of experiments on the interactions between the sample and substrate, on the physical properties of individual objects and on the creation of unusual devices incorporating the nometer objects. For example, the simple pushing of an object with the AFM tip, with the measurement of the applied lateral force, measures the surface adhesion and friction. Manipulation can be used to deform objects, and the response of the objects to large strain reveals phenomena such as buckling and fracture. After a brief review of our AFM interface development efforts, which include the application of virtual reality techniques to AFM control, I will discuss our recent results on the manipulation of carbon nanotubes. These materials have attracted a great deal of attention for their applications in advanced materials and in nanometer scale devices. Can nanotubes be used for nanometer-scale mechanical devices? We have begun to answer this question by manipulating nanotubes on substrates. Dynamical phenomena such as stick/slip, sliding and rolling have been observed. Most interesting, carbon nanotubes roll only on graphite. Can you guess why?