Lecturer: Mr. Hillel Aharoni
Affiliation: Racah Institute of Physics,
The Hebrew University of Jerusalem
Abstract:
Many systems whose intrinsic geometry is
dictated by local processes, e.g. growth.,
exhibit geometrical frustration due to the
nonexistence of a rest configuration. The
framework of incompatible elasticity
allows the description of such systems. I
will demonstrate this approach by
calculating equilibrium configurations of
chemical systems that self-assemble into
chiral ribbon structures, and explain the
equivalence of these systems to plant seed
pods which exhibit similar structures. I
will quantitatively explain the twisted-to-
helical transition which is observed
experimentally in many such systems, and
show how geometrical frustration can
cause arrest of ribbon self-assembly. I will
further use this approach to investigate the
geometries attained by thin nematic
elastomer sheets upon external stimuli,
and how these depend on the nematic
director field. I will explore the reverse
problem of constructing a director field
that will induce a specified desired
geometry, demonstrating the powerful
design capabilities of these systems.