This thesis explores the coarse-graining (CG) of complex fluids, namely polymers and liquid crystals, with a novel top-down approach using a molecular-based equa- tion of state (EoS), SAFT-γ Mie. The EoS is employed to calculate the thermophysi- cal properties of molecules provided their intermolecular interaction parameters and conversely, to obtain intermolecular interaction parameters from fits to experimental data.
Here, a systematic study of polymers is presented. Polymers are modelled as chains of homonuclear tangentially bonded spheres, with each sphere representing on average a monomer unit. Interaction parameters of six polymers are obtained by considering only small molecules containing the monomer units. A polymer of a particular molecular weight is modelled by repeating the number of spheres to match the experimental molecular weight. It is shown that the CG models proposed here are robust and can accurately predict both theoretically and in molecular dy- namics simulations the correct thermodynamic behaviour of pure polymers, as well as mixtures of polymers with solvents and other polymers including lower and up- per critical solution temperatures, the onset of miscibility and other complex phase behaviour. Polymer blends can be modelled using the same approach, indicating the extension of this work to studying block copolymers.
Polyphilic thermotropic liquid crystals are molecules which have functional groups that interact unfavourably with each other. The incompatibility between the groups within the same molecule leads to microphase separation and complex self-assembly.
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In this work, T-shaped and swallow-tail bolaamphiphiles are modelled using a het- eronuclear representation. CG models for these molecules are proposed and are used to predict and rationalize some of the most complex tiling patterns only re- cently discovered in experiments. It is shown that it is possible to predict the self- assembly structures, lattice dimensions and transition temperatures in quantitative agreement with experimental results. Extensions to surfactants, discotic liquid crys- tals and block copolymers are discussed.