Phase Behavior Of The Complex System Under Soft Confinement

Block copolymer is a kind of soft material, which can self-assemble a rich variety of ordered structures at the nanoscale. These structures have potential applications as, for example, drug delivery, photonic crystals, and high-density media storage. So the investigation of block copolymer self-assembly is becoming a hot spot in recent decades. In order to make the block copolymer self-assemble more interesting morphologies, we can put block copolymer into geometries, that is, block copolymer in confined environment to create structure. In addition, we can graft polymer on the confined surfaces, which can change the interaction between the confined surfaces and the block copolymer, and affect the self-assembly of the block copolymer. We study the phase behavior of block copolymer confined in different geometries with soft surfaces by using the self-consistent field theory(SCFT).First of all, we briefly introduce soft matter, polymer and the model of the SCFT and the types of contrained complex system.Second, in the chapter 2, we study the morphology of AB diblock copolymer confined in irregular geometries with soft surfaces. From simulation results, when diblock copolymer is confined in irregular geometry, we obtain more novel structures that cannot be observed in bulk system nor in other 2D confinement because theconfinement shapes are rather special. Second, the range of ordered lamellae formed by diblock copolymer is enlarged and the range of disordered structure is narrowed down under the concave pore compared with that by diblock copolymer under the regular square confinement. Third, the cylinders near the grooves are deviously arranged along the grooves in diblock copolymer under the irregular geometry confinement due to the effect of curvature. Fourth, the lamella orientation is inverted from horizontal direction to vertical direction by increasing the fraction of B block. In addition, when diblock copolymer is confined in concave pore, certain structures have rotational symmetries, whereas most structures formed by diblock copolymer have central symmetries except for rotational symmetries under concave pore with two grooves.Third, in this chapter, we study the phase behavior of ABA star triblock copolymers and nanoparticles mixture confined in soft cylindrical pore. We discuss the effects of block ratio, nanoparticle concentration, nanoparticle radius and cylindrical pore radius on the morphology of the mixture. The copolymers can form ordered structures in advance when add nanoparticles in this system than that in single system. Second, whether the nanoparticles interact with the B blocks or interact with both the A blocks and the homopolymer brushes, the multiple-continuous structures are formed with the nanoparticle concentration increasing. We also find that the nanoparticle concentration and the nanoparticle radius have synergistic effect on the morphologies of the mixture. Finally, we study the effect of confinement on the phase behaviors of the system and obtain the phase sequence of the mixture confined in a cylindrical pore with soft surface, which is different from that in the hard cylindrical confinement and the lateral hexagonal confinement.Finally, in chapter 4, we make the conclusions from the two works, which may provide a useful guide for the related study.