Ricerc@Sapienza

Building novel materials by designing and engineering the basic nanosized building blocks like molecules or supramolecular assemblies is the foundational goal of modern nanotechnology. Nanomaterials may have a huge number of applications such as in medicine, consumer products and electronics. Very promising candidates are provided by chiral self-assembly-driven liquid crystals, where chiral particles reversibly self-assemble into supramolecular structures before forming liquid crystal phases. Self-assembly-driven liquid crystals can be obtained from water suspensions of short/long DNA duplexes, chromonics, G-quadruplexes, amyloid fibrils, nanocellulose and ad-hoc DNA origami. Liquid crystal materials are in a thermodynamic state in between the disordered liquid phase and the fully ordered crystal phase. If constituent particles are chiral they may form cholesteric liquid crystals, which have spatial correlations which extend to dozens of nanometers. In these systems, on which we will focus within this project, all-atom computer simulations are highly demanding, not to say impracticable, because the number of simulated atoms is very large. To tackle this problem we plan to improve an existing theoretical approach, which at present neglect electrostatic interactions and account for particle flexibility too simplistically, to calculate thermodynamic, elastic and chiral properties and we will resort on highly coarse-grained modelling for carrying out computer simulations. Main goal of this proposal is to provide a quantitative description of macroscopic elastic and thermodynamic properties of chiral self-assembly-driven liquid-crystal systems through a suitable microscopic theoretical treatment which will fill the huge gap between microscopic and macroscopic levels in these systems. A stringent validation of the theory will be provided by comparing theoretical predictions and experimental results for suspensions of short DNA duplexes.