Dynamics of aging soft matter
Condensed Matter lunchtime seminar
Dynamics of aging soft matter
- Event time: 1:00pm
- Event date: 12th February 2001
- Speaker: Luca Cipelletti (Université Montpellier II)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Event details
We use multispeckle dynamic light scattering to study the dynamics of
aging soft materials. Results for gels formed by aggregating colloidal
particles will be presented. Even though the gel is an elastic solid, the
dynamic structure factor f(q,t) exhibits a nearly complete decay on long
time scales, with an unusual form, f(q,t) ~ exp[-(t/tf)m],
with m ~ 1.5
and with the relaxation time tf ~ q-1. A model for restructuring of
the gel with aging correctly accounts for this behavior. Aging leads to a
dramatic increase in the relaxation time; however all data can be scaled
on a single master curve, with the relaxation time asymptotically growing
linearly with age. This behavior is strikingly similar to that predicted
for aging in disordered glassy systems, offering convincing proof of the
universality of these concepts. I'll also present results on other soft
materials, such as micellar polycrystals and concentrated emulsions, for
which the same form of f(q,t) and the same tf ~ q-1 dependence are
observed as for the gels, thus suggesting the generality of this behavior.
References:
[1] Aging of Colloidal Fractal Gels, webpage related to L.C.'s research at Harvard University
[2] Universal Aging Features in the Restructuring of Fractal Colloidal Gels, Phys. Rev. Lett. 84, 2275 (2000)
References:
[1] Aging of Colloidal Fractal Gels, webpage related to L.C.'s research at Harvard University
[2] Universal Aging Features in the Restructuring of Fractal Colloidal Gels, Phys. Rev. Lett. 84, 2275 (2000)
About Condensed Matter lunchtime seminars
This is a weekly series of informal talks given primarily by members of the institute of condensed matter and complex systems, 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..