The Main Research themes and Expertise are:
Molecular Modelling, Computer Simulations (Monte Carlo and
Atomistic and Coarse Grained Molecular Dynamics) and Spectroscopic
(Fluorescence, ESR, NMR) investigations of
Liquid Crystals, Polymers, Membranes, Proteins and other
Soft Materials in the bulk or nanoconfined.
We aim to clarify the mechanisms of formation of specific
molecular organizations and nanostructures starting from molecular
properties.
We are interested both in static (order parameters, distributions)
and dynamics (correlation functions) in a variety of systems and in
particular in anisotropic systems in the bulk, nanoconfined, and
close to surfaces
We develop methodologies for simulations (e.g. to investigate
chirality in proteins) and for analyzing experimental data. For
instance we analyze ESR spin probe technique data to
obtain order and fluidity in nanoconfined nematics (polymeric
holographic masks), or in nematics with dispersed nanoparticles or
in polymer dispersed liquid crystals (PDLC, H-PDLC)).
Most of the research activity of C. Zannoni and his group
is in the field of liquid crystals and anisotropic soft
materials using theory, computer simulations and various
spectroscopical techniques. The work has led to around 250
publications (H=40) in international journals or multi-author
books, particularly on: Modeling and Computer Simulations (Monte
Carlo, Molecular Dynamics) of lattice (Lebwohl-Lasher), molecular
(Gay-Berne) and Atomistic Models and Statistical Theories of bulk
and confined Liquid Crystals.
Lattice models are used to investigate orientational properties
and phase transitions of a variety of 3D, 2D, 1D bulk systems, but
also to model displays and to simulate defects in droplets
and in hybrid films and the effect of external fields. We study
nanoconfined systems, in particular the effects on order and memory
of nanoparticles and polymer fibrils dispersed in nematics. We also
investigate differences in the optical textures of uniaxial and
biaxial nematics.
Gay-Berne (GB) systems are molecular resolution models employed to
study various bulk phases and their transitions. Modeling of liquid
crystal properties resulting by simple changes in the molecular
structure, particularly due to changes in shape (rod, disk,
tapered, bowlic) or electrostatic effects . We have simulated at
molecular level liquid crystal displays and developed generalized
versions of the GB potential that allow non-uniaxial, chiral,
soft and deformable shapes. Using these models we have
succeeded in simulating thermotropic biaxial nematics and a
ferroelectric nematic designed from tapered molecules by suitably
combining repulsive and attractive interactions. We have extended
the GB model further to model LC polymers and elastomers as
anisotropic beads and springs in bulk and nanoconfined systems.We
are now interested in studying (1) LC with the inclusion of
nanoparticles, fullerene and nanotubes (2) surface wetting
properties
Atomistic simulations of Liquid Crystals. We model geometry and
charge distribution of liquid crystal (LC) molecules using Quantum
Chemistry techniques to simulate and predict, using Molecular
Dynamics, their properties and phase transitions. Recently we have
succeeded in obtaining LC phase transition temperatures and in
reproducing and predicting for the first time detailed bulk and
properties for liquid crystals (e.g. cyanobiphenyls) and
their alignment close to solid surfaces (silicon, glass,
..).
We have also investigated a variety of organic functional materials
for applications in organic electronics, studying the relation of
charge and energy transport to molecular organizations using
atomistic simulations.
We are now interested in extending the atomistic predictive work to
other solid and liquid interfaces. As for organic electronic
applications we are also particularly interested in ordering at
surfaces and ensuing properties.
Development of theories and of data analysis methodologies for the
study and characterization of liquid crystalline materials,
including polymers and lipid membranes, with various techniques:
Fluorescence Depolarization, ESR, NMR, Dielectric Relaxation,
particularly for the determination of their order parameters and
dynamics.
ESR spin probe methods are now used to study probes in nematic
with dispersed nanoparticles and examine changes in order and
dynamics.
