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SUMMARY:Modelling Smectic Liquid Crystal Elastomers - Adams\, J (Universit
 y of Surrey)
DTSTART:20130627T104500Z
DTEND:20130627T113000Z
UID:TALK45952@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Liquid crystal elastomers (LCEs) are rubbery materials that co
 mposed of liquid crystalline polymers (LCPs) crosslinked into a network. T
 he rod-like mesogens incorporated into the LCPs are have random orientatio
 ns in the high temperature isotropic phase\, but can adopt the canonical l
 iquid crystalline phases as the temperature is lowered. In this talk I wil
 l describe some modelling work of the layered smectic phase of LCEs.\n\nSm
 ectic liquid crystal elastomers have highly anisotropic mechanical behavio
 ur. This arises in side chain smectic-A systems because the smectic layers
  behave as if they are embedded in the rubber matrix [1] (the same cannot 
 be said of main chain smectic systems). The macroscopic mechanical behavio
 ur of these solids is sensitive to the buckling of the layers\, so it is a
  multiscale problem. A coarse grained free energy that includes the fine-s
 cale buckling of the layers has been developed [2]\, which enables continu
 um modelling of these systems. I will describe how this continuum model\, 
 when augmented with an additional energy term describing layer buckling an
 d other effects such as finite chain extension\, can be used to model defo
 rmation of smectic-A elastomers in different experimentally accessible geo
 metries.\n\nModelling smectic-C elastomers\, with their tilted director\, 
 present a bigger challenge to calculating their coarse grained energy. The
  constraint placed on the director by the layer normal results in some unu
 sual properties of their soft modes such as negative Poisson ratio. I will
  describe the geometry of these deformation modes in smectic-C elastomers 
 [3].\n\n[1] C. M. Spillmann et al\, Phys. Rev. E 82\, 031705\, (2010). [2]
  J. Adams\, S. Conti and A. DeSimone\, Mathematical Models and methods in 
 Applied Sciences\, 18\, 1 (2008). [3] A. W. Brown and J. M. Adams\, Phys. 
 Rev. E\, 85\, 011703 (2012) .\n
LOCATION:Centre for Mathematical Sciences\, Meeting Room 2
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