【作者】 徐丹；

【导师】 吕中元；

【作者基本信息】 吉林大学 ， 物理化学， 2018， 博士

【摘要】 随着技术的不断进步以及需求的不断提高,工业上对精密器件的尺度要求也越来越严格。传统的光刻蚀制备元器件技术在尺寸上已经达到了瓶颈,而嵌段共聚物的微观相分离行为为微小尺度的元器件制备开辟了一条新道路。近年来,经过物理或者化学修饰的模板诱导嵌段共聚物的自组装获得了很广泛的关注,越来越多的研究人员对其进行了广泛且深入的研究。随着计算机运算能力突飞猛进的提升,计算机模拟技术在科学研究中也扮演了越来越重要的角色。计算机模拟以其独特的优点,可以为实验工作提供丰富的定性预测,同时也可以为动力学性质的研究提供一个非常好的方法。本文的主要研究内容包括:(1)经过化学修饰的模板可以诱导嵌段共聚物自组装形成规整有序相结构,我们重点研究对模板进行化学修饰的过程中,修饰链的链长分布问题。我们将之前发表过的一种聚合反应模型推广到缩聚反应的应用中。用耗散粒子动力学模拟的方法描述短链聚合形成长链的过程,主要针对自由体系中的聚合反应以及平板受限下的聚合反应。该方法考虑了聚合反应的活化能等化学细节,使用固定的反应速率常数来描述聚合反应过程。并且设计了渐进成键的方式。我们研究讨论了不同柔性的反应基元在自由及受限两种情况下链长的数量分布情况。(2)针对经过物理修饰的模板诱导嵌段共聚物自组装的问题,我们使用耗散粒子动力学模拟方法研究物理修饰的模板对嵌段共聚物自组装的影响。我们使用的基于粒子的模拟方法能够更真实地描述自组装的动力学过程,并且模拟过程方便、灵活。研究内容为两方面:第一,我们研究了之前较少被报道的六方排列的纳米柱对嵌段共聚物自组装的影响。当纳米柱排列形式为六方排列时,纳米柱间距这一变量只有一个值,更便于实验中的调控。第二,我们设定模板中的纳米柱吸引二嵌段共聚物中的长嵌段,不同于以往普遍使用的吸引短嵌段的情况。这种情况可以防止由短嵌段形成的条状相被纳米柱破坏结构。我们通过调控模板与二嵌段共聚物粒子间的相互作用参数来表示模板与长嵌段相互吸引的作用。通过对比不同条件下最底层以及次底层受到模板诱导的自组装形貌,给出了这两种研究情况下二嵌段共聚物受诱导情况下自组装的规律。(3)在最后一章的内容中,我们使用耗散粒子动力学模拟的方法实现了三维目标结构模板的反向设计。由于该模拟方法中势能柔软的特点,模拟过程中体系更容易跨越自由能垒。我们首先重现了文献中的二维“Ψ”型图案模板的反向设计。进而将目标结构拓展至三维结构,使用纳米粒子替代纳米柱作为构成模板的基本单元。采用了在工业中以及“3D”打印中有应用价值的三维“井”状目标结构。在此工作基础上,我们使用两种共混的均聚物替代二嵌段共聚物作为被模板诱导的原材料。我们的结果也表明:在受到与聚合物有相互作用的模板的诱导下,两种共混的均聚物也能和二嵌段共聚物一样,被成功诱导出目标结构。更多还原

【Abstract】 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 Ψ-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.更多还原