Wrapping threads around spheres

Condensed Matter lunchtime seminar

Wrapping threads around spheres

  • Event time: 1:00pm
  • Event date: 9th July 2001
  • Speaker: Matthias Fuchs (University of Edinburgh)
  • Location: Room 2511,

Event details

Free polymers which are added to suspensions of colloidal hard sphere particles induce attractions among the particles. These depletion attractions are rather well understood as long as the polymer coils are much smaller than the particles. Considering the opposite limit in size ratios, polymer coils which are much larger than the spheres, strikingly contradictory predictions can be found in the literature. Whereas de Gennes predicted that only weak attractions are induced which cannot lead to phase separation, Sear recently predicted that phase separation takes place at smaller and smaller colloid concentrations for increasing polymer size. Experimental observations and some theoretical arguments will be given trying to disentangle the threads, and to stress the need for more studies. P.G. de Gennes, C. R. Acad. Sci. Paris 288B, 359 (1979)
R. Sear, Phys. Rev. Lett. 86, 4696 (2001)
other references can be found here.

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..

Find out more about Condensed Matter lunchtime seminars.