title: Fast switching from isotropic liquids to nematic liquid crystals: rotaxanes as smart fluids.
abstract: We examine a solution of rod-like piston-rotaxanes, which can switch their length by external excitation (for example optically) from a short state of length L to a long state of length qL. We show that this solution can exhibit a number of different behaviours. In particular it can rapidly switch from an isotropic to a nematic liquid crystalline state. There is a minimum ratio q* = 1.13 for which transitions from a pure isotropic state to a pure nematic state are possible. We present a phase-switching diagram, which gives the six possible behaviours for this system. It turns out that a large fraction of the phase switching diagram is occupied by the transition from a pure isotropic to a pure nematic state.
authors.affiliation: Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Hao
authors.initials: H
authors.lastname: He
authors.affiliation: Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Edith M
authors.initials: EM
authors.lastname: Sevick
authors.affiliation: Department of Applied Mathematics, Research School of Physical Sciences & Engineering, The Australian National University, Canberra, ACT 0200, Australia. D.Williams@anu.edu.au.
authors.forename: David R M
authors.initials: DR
authors.lastname: Williams