Much of the research in my group is focused on the broad area of soft condensed-matter physics. Soft materials are materials in which "the thermal fluctuations that dominate the fluid state coexist with the stringent constraints characteristic of the solid state" [Witten, Reviews of Modern Physics 71, S367 (1999)]. Well known examples include polymers, in which subunits are joined covalently to form a flexible chain, and liquid crystals, which exhibit some, but not all, of the ordering seen in solid crystals. In order to understand the structure of such materials, we employ atomic force microscopy, video microscopy, and small-angle neutron scattering. If you would like to learn more about our work, please explore some of the specific projects listed below...
One thing we study is the crystallization of normal alkanes - paraffin wax. Although this might seem mundane at first glance, there are several reasons to study this system. More info ...
Through a collaboration with research groups in Biomedical Engineering and the Medical Sciences, we are performing atomic-force microscopy studies of biological cells in order to better understand their structure, mechanical properties, and adhesive properties. More info...
Hydrogels are another class of soft material we are investigating. Hydrogels are typically comprised of a sparse network of cross-linked polymers imbedded in a fluid matrix - one well-known example is Jello. More info...
The ability of the AFM to measure forces at the pico-Newton scale with nanometer lateral resolution is well suited to the study of nanomaterials such as carbon nanotubes. More info...
One of the primary experimental instruments employed in my research is the atomic force microscope (AFM), which can measure structures and forces at the nanometer and pico-Newton levels. Still only 20 years old, development of new AFM techniques continues. More info...
An important application of the atomic force microscope is in quantitative force measurements, a prerequisite of which is accurate knowledge of the cantilever spring constant. Although several calibration methods have been described in the literature, one must often wade through numerous publications in order to track down all of the details. Here, we briefly review three popular methods and single out one the thermal noise method for a detailed description. More info...
Although an old technique, advances in microscopic techniques, such as phase constrast and differential interference contrast, have maintained the usefulness of this tool. An excellent primer is available on-line.
Wax crystals seen through a
polarizing optical microscope
A much more modern microscopic method, scanning-probe microscopes allow nanometer-scale measurements of properties such as:
AFM map of the centre of a
spherulitic multicrystalline domain
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Last updated July 16, 2005