AVS 50th International Symposium
    Nanometer Structures Wednesday Sessions
       Session NS-WeM

Invited Paper NS-WeM5
Mechanics at the Nanoscale

Wednesday, November 5, 2003, 9:40 am, Room 308

Session: Nanomechanics
Presenter: S.P. Jarvis, Trinity College, Ireland
Authors: T. Uchihashi, Trinity College, Ireland
M. Higgins, Trinity College, Ireland
J.E. Sader, E.T.S. Walton Visitor, Trinity College, Ireland
S.P. Jarvis, Trinity College, Ireland
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Atomic force microscopy (AFM) evolved from the observation of the effects of mechanical contact in the scanning tunnelling microscope. Thus, even from its first inception, nanomechanics and atomic force microscopy have been inextricably linked. Whilst not all mechanical phenomena have been intentional or welcomed in AFM measurements there has also been a concerted effort to apply AFM to the investigation of mechanics at the nanoscale. Due to its highly localised measurement ability, the microscope can be applied to characterise the mechanical response of materials too laterally specific to be investigated by Surface Forces Apparatus or nano-indentation devices. For example, measuring mechanical responses with a probe of lateral dimensions comparable to that of a single molecule provides an invaluable insight into the processes controlling if and how a molecule approaches another molecule or a membrane and how mechanical property variations in any intervening fluid can modify that interaction. We introduce a significantly modified AFM which includes the ability to control the force sensor directly via a magnetic field in order to make sensitive dynamic measurements and direct stiffness measurements. In addition, to isolate the measured interaction to the tip apex we have used a multiwalled carbon nanotube attached to the tip. For the extension of the method to include lateral activation, and hence open up the possibility of measuring local viscosity, a new shape of cantilever has been used. To understand the mechanics of our new force sensors we have employed finite element analysis (FEA) to assess and improve the design and for calibration.