A recipe for making glasses at any temperature through topology
The glass transition is commonly associated with a reduction in the temperature of liquids or by an increase in density of granular materials. In this talk, I will show that a radically different pathway can be taken in the case of dense solutions of ring polymers. This system has been shown to display so-called "threading configurations", in which a ring may pass through the contour of another thereby generating a proliferation of topological constraints. By exploiting these, I will show that a concentrated solution of ring polymers can be driven to a kinetically arrested state by randomly pinning a small fraction of rings, c, and that a spontaneous vitrification (at T>Tg) may occur in the limit c->0 for long enough rings.
Since this strategy only relies on the existence of constraints in the system due to the topology of the constituents, it may be successfully applied to other systems featuring components with non-trivial topology.
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..