Chromonic mesogens are non-conventional amphiphiles, which self-assemble in aqueous solution to form aggregate structures: rods, stacks or layers. These aggregates can subsequently self-organise to form chromonic mesophases. Initial self-assembly is strikingly different to that seen in most conventional amphiphiles: it is enthalpically-driven and takes place in the absence of a critical micelle concentration. At sufficiently higher concentrations, mesophase formation is induced by excluded volume interactions between aggregates. However, in principle, mesophase formation can also induce a change in aggregation. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/239nm/uploads/2861_untitled.jpg' alt='' /> This paper demonstrates that the key features of chromonic aggregation in water can be reproduced using long atomistic simulations, and aggregation free energies can be measured directly from simulation studies. However, the formation of large aggregates and self-assembled mesophases requires coarse-grained simulation approaches. We show that simple coarse-grained models, parameterised by reference to atomistic calculations, can be used to reproduce self-assembled mesophases and make predictions of how mesophase formation is influenced by molecular structure.Results are presented for the food dye sunset yellow (edicol), a triphenylene derivative (TP6EOM) and a cyanine dye (B15920). In the case of the latter, we show that experimental data on aggregation can be reinterpreted by using a combined simulation and experimental approach.

Simulation studies of aggregation in aqueous solution using atomistic and coarse-grained approaches

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.