1 research outputs found
Soft elasticity in biaxial smectic and smectic-C elastomers
Ideal (monodomain) smectic- elastomers crosslinked in the smectic-
phase are simply uniaxial rubbers, provided deformations are small. From these
materials smectic- elastomers are produced by a cooling through the
smectic- to smectic- phase transition. At least in principle, biaxial
smectic elastomers could also be produced via cooling from the smectic- to a
biaxial smectic phase. These phase transitions, respectively from to and from to symmetry, spontaneously
break the rotational symmetry in the smectic planes. We study the above
transitions and the elasticity of the smectic- and biaxial phases in three
different but related models: Landau-like phenomenological models as functions
of the Cauchy--Saint-Laurent strain tensor for both the biaxial and the
smectic- phases and a detailed model, including contributions from the
elastic network, smectic layer compression, and smectic- tilt for the
smectic- phase as a function of both strain and the -director. We show
that the emergent phases exhibit soft elasticity characterized by the vanishing
of certain elastic moduli. We analyze in some detail the role of spontaneous
symmetry breaking as the origin of soft elasticity and we discuss different
manifestations of softness like the absence of restoring forces under certain
shears and extensional strains.Comment: 26 pages, 6 figure