Template confinement effects on discotic liquid-crystals – TEMPLDISCO

The present project develops a fundamental and experimental approach of the chemical physics of discotic columnar liquid crystals (DCLC) when they are confined at the nanometer scale in porous highly ordered templates. It addresses ground-breaking generic systems that are directly relevant for short-term applications in organic electronics, but for which advanced knowledge of structural and dynamical properties is still lacking and remains a scientific lock. For this purpose, we build a consortium in order to combine and benefit from the scientific and technical expertise of French and German research teams with international recognition in the domains of the physical chemistry of liquids, glass-forming systems, soft matter and confinement. Moreover a wide range of different scientific experiences like organic chemistry, inorganic template preparation, structural and dynamical characterization are combined and interrelated. The foremost necessity to control both the nature and the kinetics of formation of the supramolecular order within DCLC nanowires calls for a prior understanding of the generic effects of confinement on DCLC. This is expected to be the main output of the present project. The role of some key-parameters will be analyzed in detail: surface interaction, roughness of the interface, thermal treatment on the nature and the spatial homogeneity of the obtained structures. A large part of the project will involve experiments done on european large scale facilities. The complementarity of expertises and equipments (NMR, dielectric spectroscopy, quasielastic neutron scattering) will allow to explore the molecular dynamics of confined DCLCs on a very broad range of correlation times. Characterization of the single-particle motion (translational and rotational modes) from a microscopic to a macroscopic time-scale will allow to monitor the expected glass-like slowdown of the molecular dynamics on cooling, and to determine the size of the dynamical heterogeneities and quantify other relevant length scales. It should be emphasized that especially the latter point is a topical issue of soft matter physics. Some indicators will help to evaluate the success of the project: the characterisation of the nature of the phase transitions encountered for a variety of representative DCLC confined in porous nanochannels, confrontation to expectations derived from finite size, external field and quenched disorder effects.