Hong Liu（Associate Professor）-Zhong-Yuan Lu

My current research mainly focuses on the computer simulation study of polymerization by the coarse grained DPD and MD method. As is known, there is a competition between phase separation which is demixing the different species and the polymerization which is mixing the particles. This topic relates to the material processing in industry: the reactive injection molding (RIM) technology is widely used. However, accompanied with the reactions, phase separation may take place in the mold, which will strongly affect the mechanical properties of the final products. Therefore, it is very necessary to study the coupling between the two dynamic processes. Besides, I have developed a special practical method of avoiding bond crossing in 2d-DPD, in which a two dimensional geometry constraint condition and a kind of mathematically analytic geometry method has been originated to solve this problem. This approach is proved can be used in any simulation models when they are aimed to study the two dimensional polymer systems with long chain lengths. Recently, I am developing the simulation of the surface initiated polymerization by the truncated-shifted Lennard-Jones potential and FENE bond force, mainly focusing on the polymerization rate effect on the growth of surface tethered polymer brushes. In this system, the simulation result implies that polymerization rate and initiator density together determine the density of the polymer brushes. The denser polymer brushes have to suffer the excluded volume effect obviously. All of the conclusions may give a general advice to industrial preparation of polymer brushes.

IN THE FUTURE:

I wish to extend my research to the influences of shearing, the molecular structures and the multi-type reactions on the spinodal decomposition, and the effect of the competition between microphase separation of block copolymers and the macrophase separation of polymer blends. In the future, simulation study of the generation of polymers with complicated structures will be carried out, e.g., the polymerization of hyper-branched or cross-linked polymers. Besides, some special processes such as chemically degradation, generation the molecules with ligands or with hydrogen bond will be taken into account. Also, advanced work in extending the methods to bio-systems is of great interest to him.