Self–Consistent Field Theory And Kinetics Of Non–isothermal Phase Separation For Polymeric Complex Fluids

Phase separation in polymeric complex fluids is the key problem in the field of condensed matter physics. And studies on this topic are essential not only for understanding the non-linear phenomena in complex systems, but also for designing polymer materials with high-performance. In this thesis, inhomogeneous polymer systems are studied on the basis of self-consistent field theory for obtaining ordered morphologies. Moreover, kinetics of non-isothermal phase separation in binary polymeric mixtures is numerically studied based on Cahn-Hilliard-Cook (CHC) theory. The details are specified as follows.1. A self-consistent field theory forα,ωbranched copolymers is developed, which can be extended to copolymers with any topological architecture. By solving self-consistent field equation set numerically, ordered morphologies ofα,ωbranched copolymers with H shaped,πshaped and heteroarm architectures are simulated. Lamellae and hexagonal lattice phase obtained for H shaped andπshaped respectively are consistent with experimental results. Once the length of the chemically identical chains, belonging to H shaped orπshaped copolymers, are different, long chains are isolated to interiors of the phases, whereas short chains are concentrated at the domain interfaces. As for heteroarm copolymer, the morphologies of phase separation depend on the total fraction of different spices. Also, simulation reveals that the junction points lie on the microphase interfaces.2. The density profiles in a mixture of bidisperse polymer brushes and solvent are simulated with the aid of a self-consistent field theory. The results show the formation of two polymer sublayers in good solvent, which is in agreement with experiments. Furthermore, the validity of strong segregation theory (SST) is discussed according to the comparison between the results of SST and SCFT. When the bidisperse brushes are in a good solvent, the density profiles in the inner layer are dependent on the total grafting density, and irrelevant to grafting densities of long and short chains respectively. Also, segment distribution of long (short) chains in bidisperse brushes is narrower than that of chains with the same length in monodisperse brushes. And the long chains are localized in a good solvent.3. The process of periodic phase separation is numerically studied based on Cahn-Hilliard-Cook theory for a binary polymer blend. Hierarchic morphologies consisting of large and small domains are observed, which are confirmed by...