Control On Self-assembly Ordered Structures Of Diblock Copolymer And Dynamics Research

Diblock copolymer can self-assemble into rich and multi-scale ordered structures under different control measures.The properties depend on the structures of the system,so these novel ordered structures with special function proper ties have great potential applications.This paper mainly focus on the control on self-assembly ordered structures of diblock copolymer and dynamics research.We used the Cell Dynamics Simulation(CDS)and Brown Dynamics(BD)methods to study the self-assembly behaviors and growth kinetics of the symmetrical/asymmetrical diblock copolymer induced by oscillatory shear field and cylindrical confinement,and nanorods with different surface chemistry.The main content is as follows:In the first chapter,we reviewed the recent research progress of the self-assembly of diblock copolymer in the bulk and induced by cylindrical confinement,shear flow,and nanoparticles.Meanwhile,the thermodynamic and kinetic theory of phase separation in polymer system,and the methods of Cell Dynamics Simulation(CDS),the Brown Dynamics(BD)were chiefly introduced.In the second chapter,we combined two different control measures of cylindrical confinement and oscillatory shear flow to manipulate the self-assembly nanostructures and obtained novel morphologies.Specifically,we predicted the phase behavior of diblock copolymer confined in nanopore under oscillatory shear.By changing the degree of confinement D/L0(D is the diameter of the cylindrical nanopore,L0 is the domain spacing),shear amplitude,and shear frequency,we studied the influence on the phase behavior of the amplitude and frequency in different confinement environments.Simultaneously,the dynamic mechanism of microphase transition of diblock copolymer was e xplored.Thus,it provide an easy method to create the ordered,defect-free nanostructured materials for an experimentalist through the combined control measures of the cylindrical confinement and oscillatory shear flow.In the third chapter,we performed computer simulations to investigate phase transition of the symmetric diblock copolymer induced by nanorods with different surface chemistry.As increasing the number of nanorods,the system occur red the phase transition from a disordered structure to the ordered parallel lamellae and then to the tilted layered structure.The oriented parallel lamellar structure of the polymer system and the side-to-side alignment of rods that were almost vertical to the interface were theoretically analyzed in detail.Also,we examined the dynamic evolution of domain size and the order parameter of microstructure.We investigated the pattern evolution and the domain growth of the ordered parallel lamellar structure as well.In addition,we also investigated the influence of the rod property,the rod-phase interaction,rod-rod interaction,and the polymerization degree on the phase separation.Our simulations provide an efficient method for determining how to obtain the ordered structure on the nanometer scales and design the functional materials with optical,electronic,and magnetic properties.In the fourth chapter,based on the Cell Dynamics Simulation(CDS)and Brown Dynamics(BD),we studied the microphase transition of the asymmetric diblock copolymer induced by nanorods with different properties.By increasing the length of A-like sites of the rod,it occurred the phase transition from the tilted layered structure to parallel lamellae,to perpendicular lamellae,and then to “sea-island” structure.The alignment of nanorods transformed from end-to-end to side-to-side,and then to aggregate.For this transition,we further examined the dynamic evolution of domain size and the order parameter of microstructure.And we also investigated the pattern evolution and the domain growth of the ordered parallel/perpendicular lamellar structure as well.Additionally,we explored the effect of the number of single-wetting nanorods on the phase behaviors of polymer system.Finally,we investigated the effects the rod-phase interaction,rod-rod interaction,and the polymerization degree on the phase behaviors of asymmetric diblock copolymer.Finally,in the fifth chapter,the main conclusions of this paper were summarized,and the future work were presented.