Hosted by: Alexei Tkachenko

Self-assembling materials have been extensively studied in recent years. It is now possible to achieve a considerable degree of complexity using simple building blocks. For example, using computer simulations, we have found that 2D particles with regularly arranged 'patches' spontaneously form dodecagonal quasicrystals in certain conditions. I will show that the quasicrystal phase has the lowest free energy over a range of conditions and is stabilized by its greater configurational entropy over the crystalline phases. The patchy particles of the model can be thought of as a coarse-grained representation of DNA multi-arm 'star' motifs. I will present several possible design strategies to construct soft two-dimensional DNA-based quasicrystals. However, simple building blocks such as these can only go so far and self-assembling truly 'complex' structures requires us to introduce more distinct building blocks into the system, which makes the problem of self-poisoning ever more difficult to counter. In 2012, Ke and co-workers reported that DNA bricks successfully self-assembled into structures containing not just a handful, but hundreds of distinct components [Science 338, 1117 (2012)]. However, it is not immediately obvious why such self-assembly should succeed where colloidal systems have failed. In my talk, I will present our computational and theoretical work explaining how nucleation governs the self-assembly of these many-component systems and the role this plays in the rational design of the target structure.