Metal oxides (MO) play a leading role in nanotechnology where nanometer-sized particles are routinely used as pigments for paints, supports for catalysts, as base components in cosmetics, medical ointments and lubricants, and in opto-magneto electronic materials e.g. as MEMS devices and novel sensors. Understanding how waxy molecules interact with and modify MO materials will unquestionably enhance their technological usage. We have used neutron diffraction to study the arrangement of molecular species on MO surfaces. We have found that a single ‘2D’ layer of butane (C4H10) on MgO is sawtooth shaped. The structure results from the attractive force of the MgO surface ‘pulling’ the molecules into registry with it. MgO has a similar ‘attraction’ for longer-chain pentane (C5H12) and hexane (C6H14) molecules. This work is part of a comprehensive investigation into the adsorption, structural and dynamical properties of alkane films on nanocubes of MgO and represents a key step towards developing accurate and realistic models of the interplay between adsorbate-adsorbate and adsorbate-substrate interactions. Knowledge of these forces will ultimately lead to the production of nanomaterials that have predictable physical and chemical properties.
P Yaron, R Cook (University of Tennessee, USA), SA Clarke (BP Institute and University of Cambridge), T Arnold (Diamond Light Source), MTF Telling (ISIS), JZ Larese (University of Tennessee and ORNL, USA)
Research date: December 2006
Prof JZ Larese, [email@example.com] T Arnold et al., Phys Rev B (2006)