Optical Trapping Experiments in Hard Sphere Colloidal Systems
- Event time: 1:00pm
- Event date: 27th March 2006
- Speaker: Laurence Wilson (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
The technique of optical trapping has been used to give new understanding of soft condensed matter systems. Our calibrated force-measurement system allows us to reach inside a complex system to examine and manipulate micron- and sub-micron-scale objects to investigate the effect of a mechanical stimulus on the local environment. A range of volume fractions have been examined, up to and above the glass transition, using both passive (particle held still in suspension) and active (particle dragged through suspension) techniques. The preliminary results in low volume-fraction systems broadly agree with existing diffusive-wave spectroscopy results of Weitz and co-workers, while the active results give new insight into the nature of caging in colloidal glasses.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..