My PhD research mainly focuses on studying the self-assembly process by computer simulations. In addition to the thermodynamics, the kinetics also play an important role in determining the morphology of the self-assembled nano-structures. However, the self-assembly process is often out-of-equilibrium and may involve multiple parallel pathways. Thus, it is highly challenging to systematically elucidate the dominant kinetic pathways of self-assembly processes. To address the out-of-equilibrium problem, we developed a new scheme to construct kinetic network models based on the mass flow between different states to elucidate the kinetic pathways. We successfully applied this scheme to the self-assembly of two classes of systems: star-like block copolymers and patchy particles. For t...[ Read more ]

My PhD research mainly focuses on studying the self-assembly process by computer simulations. In addition to the thermodynamics, the kinetics also play an important role in determining the morphology of the self-assembled nano-structures. However, the self-assembly process is often out-of-equilibrium and may involve multiple parallel pathways. Thus, it is highly challenging to systematically elucidate the dominant kinetic pathways of self-assembly processes. To address the out-of-equilibrium problem, we developed a new scheme to construct kinetic network models based on the mass flow between different states to elucidate the kinetic pathways. We successfully applied this scheme to the self-assembly of two classes of systems: star-like block copolymers and patchy particles. For the star-like block copolymer system, we found that the dominant pathways are controlled by the inter-aggregate encounter time ?_? and intra-aggregate morphology transition time ?_?. Furthermore, we successfully altered the dominant self-assembly pathways by rational design of ?_?. For the patchy particle system, we found that the formation of the C20 fullerene-like cage consists of two stages: size increasing stage and structure rearrangement stage. Based on these mechanistic insights, we rationally designed a new type of patchy particles that can obtain a higher fraction of the C20 fullerene-like cage structures. To address the multiple-pathway problem, we developed a novel algorithm that can efficiently group a large number of parallel pathways into path channels according to their connectivity in kinetics. This algorithm has been successfully applied on the self-assembly of two different amphiphilic molecules: PYR and PYN. We found that these two molecules prefer different kinetic self-assembly pathways which lead to different self-assembled structures. In addition, we studied the membrane damage process induced by the self-assembly of human Islet Amyloid Polypeptides (hIAPPs). We identified one key intermediate state of the damage process, the insertion of monomeric hIAPP into the membrane. Finally, we investigated the structure of the cell penetrating peptides (CPPs) by computer modelling and found that the different cellular uptake efficiencies could be explained by the hydrophobic moments of these CPPs.