Understanding the Pitch Sensitivity of Chiral Materials – UPSCALE

Helical molecular assemblies are amongst the most fascinating structures
found in nature. Prominent examples are chiral nematic liquid crystals
which are of immense technological importance due to their ubiquitous use
in optical switching devices. The size and symmetry of the helical pitch
endow these helical materials with a high level of complexity and
performance owing to their extraordinary optical and mechanical functions.
Accurate control and predictability of the amplitude and handedness of the
mesoscopic helical pitch is the key to understanding the fundamental
properties of chiral materials. This proposals aims to develop novel
theoretical routes towards unravelling the microscopic origins of
chirality and specifically targets the question of how chiral molecular
forces proliferate to the mesoscale. To this end generic coarse-grained
models for rigid helical objects will be considered as effective
prototypes for helical biomacromolecular mesogens such as DNA, chiral fd
virus particles or cellulose as well as synthetic objects such as
carbon-nanotubes. The self-assembly of these helical constituents will be
studied theoretically using the common numerical tools of modern
statistical mechanics including Monte Carlo computer simulation and
density functional theory. The proposed approach is expected to shed new
light on how the helical structure of the cholesteric mesophase depends on
various microscopic properties of the constituent (effective shape,
internal helical pitch) as well thermodynamic quantities such as
temperature and density. In view of potential application we envisage that
tuning the helical handedness by external control parameters such as
temperature holds great promise for the design of a new class of optical devices
with improved speed and functionality.