(15b) Design of Soft Pair Potentials for Mesophase Formation in DNA Decorated Colloids

Colloidal self-assembly is an exciting focus of the material discovery field. Colloids that interact and assemble in novel ways lead to new materials with unique physical, optical and electronic properties. DNA has proved itself a powerful tool for the design of colloidal interactions, allowing for detailed control of self-assembly processes. In this simulation project, we seek to take advantage of this control to design and evaluate coarse grained pair interaction potentials between DNA decorated colloids with the goal of creating a potential that mimics the self-assembly of block-copolymers, which have been shown to exhibit a rich range of mesophases. We achieve this through the judicious control of DNA patterning designs, DNA chain lengths, particle sizes and relative interaction distances. Proposed architectures are evaluated through free energy methods to determine their resulting interaction potentials. We then analyze the self-assembly of these systems at a coarse-grained level by modelling the decorated colloids through their average pair interactions. For relevant cases, these phases are verified through more detailed simulations. We demonstrate the potential of DNA decorated colloids to exhibit a range of mesophases analogous to that of block-copolymers, such as lamellar and hexagonal phases. Additionally, we delineate the design rules needed to induce these phases.