The Phase Behavior Of Soft-constrained Two-block Copolymer

In the era of polymers, block copolymer as an important branchof polymer system, it’s research of self-assembly has become oneof the important field. The self-assembly of block copolymer underconfinement are abundant. In the confined interface graft polymerbrushes can effectively influence the phase behavior of blockcopolymer, which have good promotion effect on the design of newmicro-structure, micro-processing technology and the design ofnew nano materials.In this paper, we study the phase behaviors of diblockcopolymer confined between templated polymer-grafted surfacesand in a soft square pore based on2D real-space self-consistentfield theory. We also investigate the influence of the symmetry ofdiblock copolymer, the concentration of polymer brush and theinteraction parameter of this system.Firstly, we study the phase behaviors of diblock copolymerconfined between templated polymer-grafted surfaces. We findnovel microstructures that have not found in hard surfaces andpolymer-grafted surfaces under confinement. Under the five kindsof templates, when we change the symmetry of diblock copolymer,the system forms a transition from cylinder to lamellar. We also find hexagonal cylindrical phase and three row cylinder when thediblock copolymer is asymmetric. The system forms a series oforderly domain morphologies and A block forms a novel structurethat is four-layers wave structure when the diblock copolymer issymmetric. Then we change the concentration of polymer brush, wefind the small change can cause a lot of change of domainmorphologies. The system forms alternant parallel strip structureand cylindrical structure and lamellar structure, we construct thephase diagram of this template. We also change the interactionparameter of this system and get the range of the interactionparameter.Secondly, we study the phase behaviors of diblock copolymerconfined in a soft square pore. We considered the influence ofnanopore with different shapes and interfacial properties on systemphase behavior, and discussed the confinement in a soft squarepore and a soft rectangular pore. In the confinement system of softsquare pore, when we change the volume fraction of A block, thesystem forms a transition from cylinder to concentric square ringstructure and cylindrical structure. Especially, we find tetragonalcylinder. Then we change the concentration of polymer brush, whentwo block is symmetry, the system forms concentric square ringstructure. With the concentration of polymer brush is decreasing,the number of concentric square rings is increasing. When twoblock is asymmetry, the system forms cylinder. With theconcentration of polymer brush is increasing, the number of layersof polymer brush is decreasing. We also find tetragonal cylindricalstructure and construct the phase diagram of this system. We also change the interaction parameter of this system and get the rangeof the interaction parameter. In the confinement system of softrectangular pore, we discussed the influence of the width of pore.When two block is symmetry, the system forms concentric squarering structure. With the width of pore is decreasing, the number ofconcentric square rings is decreasing. When two block isasymmetry, the system forms cylinder. With the width of pore isdecreasing, the number of layers of cylinder is decreasing until alayer.In conclusion, our results may provide a useful guide for thefurther experimental work, and novel microstructures may providesome help for new materials on the industry.