Self-assembly Of Block Copolymer Directed By Template

To make a precise device which has higher performance,advanced patterning process of photolithography is needed.Making smaller pattern is one of main issues for patterning.Block copolymers can self-assemble into microscopic pattern,which makes it an excellent material in future industrial manufacture.In recent years,directed selfassembly of block copolymer through physically or chemically modified templates has attracted great attention.More and more researchers have proceeded extensive and indepth researches on them.With the rapid development of computing power,computer simulation has played an important role in scientific research.Because of the unique advantages of computer simulation,it can provide rich qualitative predictions for experimental work and provide a very good method for the study of kinetic properties.The main contents of this thesis are as follows:(1)In the first section,as an application of our previous strategy,we couple the kinetic step-growth polymerization model with the dissipative particle dynamics simulation to describe a specific step-growth polymerization process in reactive polymer systems at the coarse-grained level.This model involves the chemical details in the generic step-growth polymerization protocol,e.g.,the activation energy,thus,the impediment of reaction can be reflected.It describes a step-growth process with a constant Arrhenius-type reaction rate coefficient;thus correct reaction kinetics is reproduced.This algorithm can also describe gradual processes of bond formation.To study the number distribution of chain length in chemically modified template,we focus on the generic one-dimensional linear step-growth of polymerization.The correct Flory distribution can be reproduced by our model.Furthermore,step-growth polymerization with the subunits of different flexibilities or within confinement is also investigated.(2)In the second section,we use the particle-based dissipative particle dynamics(DPD)simulation method to study self-assembly of diblock copolymer directed by physically modified template.This method is objective in describing such a self-assembly process,and besides,the different technical problems are easily to be handled in simulations.Two sets of systems,which are scarcely concerned and reported by previous literatures,will be covered in this study.The first study focuses on the self-assembly of block copolymer on a template with hexagonally arranged posts.The second study focuses on the system with rectangularly arranged posts,while we make them minorityunfavored.We regulate the interaction parameter between the uniform posts and the different polymer components to represent the selectivity of the coated template.The bottom and sub-bottom layers will be especially focused upon,since they are crucial for discovery of the true law of the dependence of the morphology on the confinement from the posts.(3)In the third section,we propose to use the dissipative particle dynamics simulation method to inversely design the template.Our inverse design strategy based on dissipative particle dynamics simulation can easily reproduce the result of the ?-like nanopattern reported in previously published article.Because of the relatively low computational cost of dissipative particle dynamics simulation,our inverse design strategy can be reasonably expanded to a three-dimensional(3D)space with the nanoparticle as the building block.A regularly and periodically arranged 3D pattern enables diverse applications of block copolymer.More importantly,we introduce the use of a binary homopolymer blend as the templating matrix,replacing block copolymer which is commonly used in conventional patterning.This study demonstrates the possible application of homopolymers as the matrix directed by template for nanolithography by using the inverse design strategy.