Many industries desire the ability to fabricate materials with specific structural features. Multicomponent systems have flexibility to self-assemble into more complex structures than are achievable within single-species systems. As they report in The Journal of Chemical Physics, researchers developed an inverse strategy to design interactions that favor the assembly of desired structures from a multicomponent colloidal fluid.

The inverse approach targets a desired assembly structure and discovers the interaction parameters by solving a constrained optimization problem. Here, the researchers extended the relative entropy (RE) optimization technique, originally developed for biomolecular simulations, to discover simplified interactions that mimic the behaviour of more detailed models. “We put the algorithm through its paces by requiring it to find pair potentials that spontaneously assemble particles into increasingly complex structures,” said co-author Thomas Truskett.

The two component system, with isotropic pairwise interactions, was able to assemble both simple and quite complex structures. Architectures were realized that had not been previously achieved either experimentally or theoretically.

The authors compared interactions between a one and two component system, providing insight into what types of interactions are required to achieve structures of different complexities. For instance, in a two component simple structure, only two of the three types of interactions required tuning, but richer structures required tunability of all three interactions.

This study forms a proof of concept, providing a systematic method for the colloidal community to search for new interactions that assemble structures of interest.

Truskett and his team are now looking to extend the approach to designing colloidal assemblies with interactions constrained to specific experimentally realizable forms.

Source: “Inverse design of multicomponent assemblies,” by William D. Piñeros, Beth A. Lindquist, Ryan B. Jadrich, and Thomas M. Truskett, The Journal of Chemical Physics (2018). The article can be accessed at https://doi.org/10.1063/1.5021648.