单链均聚物接枝球纳米粒子的自组装行为:自洽场结合密度泛函理论研究
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- 英文论文题名：Self-Assembly Behavior of Homopolymer Monotethered Nanoparticle:Self-Consistent Field Theory and Density Functional Theory Study
- 论文作者：张添财 ; 杨颖梓 ; 邱枫
- 英文论文作者：Tiancai Zhang ; Yingzi Yang ; Feng Qiu ; The State Key Laboratory of Molecular Engineering of Polymers ; Department of Macromolecular Science ; Fudan University
- 年：2016
- 作者机构：复旦大学高分子科学系聚合物分子工程国家重点实验室;
- 论文关键词：单链均聚物 ; 接枝球纳米粒子 ; 自组装行为 ; 自洽场和密度泛函理论
- 会议召开时间：2016-08-25
- 会议录名称：中国化学会2016年软物质理论计算与模拟会议论文摘要集
- 语种：中文
- 分类号：O631.1;TB383.1
- 学会代码：ZGHY
- 会议名称：中国化学会2016年软物质理论计算与模拟会议
- 会议地点：中国天津
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：2
- 文件大小：438k
- 原文格式：D
- 会议级别：全国
摘要
聚合物/纳米粒子复合材料正成为有机/无机杂化领域重要的研究方向之一。纳米粒子能改善聚合物材料的光学、电学和力学性能。聚合物基体则通过微相分离形成多种有序结构,为纳米粒子的分布提供模板。近来,程正迪课题组合成并研究了线形均聚合物一端化学接枝纳米分子粒子的结构(简称为AP分子),并发现其本体自组装成多种小于10nm的有序纳米结构[1]。为了系统地研究由柔性单链和刚性球形纳米粒子构成的AP分子熔体的自组装行为,我们采用由Thompson等人[2]发展的自洽场结合密度泛函的理论(SCFT/DFT)方法,得到以链体积分数fA和Flory-Huggins相互作用参数χ为参量的相图,如Figure 1所示。将AP分子的相图与两嵌段共聚物的相图比较[3],虽然都有层状相(L)、柱状相(C)、Gyroid相(G)、球状相(S)和无序态(disordered),但相图仍有较大的区别:(1)AP分子的相图是不对称的。在fA<0.5的区域,并没有和两嵌段共聚物一样形成的G、C、S相;(2)在0.26粒子区域,粒子总是液态排列以获得更大的平动熵。我的的理论方法适用于同时包含刚性和柔性组分的复杂体系,并容易推广到不同结构的线型链与纳米粒子的复合物体系,如单链两端接粒子的哑铃型分子。这种理论框架有助于预测有序相形貌和计算体系相图,为研究可应用于先进材料的有序纳米结构提供了有效的手段。
Polymer-nanoparticle composites are becoming an intriguing and promising issue of organic-inorganic field.The nanoparticles substantially improve optical,electrical,and mechanical properties of polymer matrix,while the melt matrices,through microphase separation,provide a template for the distribution of nanoparticles.Recently,Cheng's group synthesized and studied linear polymer monotethered nanoparticles(namely AP molecule).They reported that AP molecules self-assemble into various nanostructures less than 10 nm.[1] In order to systematically investigate the self-assembly behavior of AP molecule consisting of a flexible linear homopolymer and a spherical nanoparticle in melt,we employ the combined self-consistent field theory and density functional theory(SCFT/DFT),which was first developed by Thompson et al [2].We studied the microphase separation of AP molecule by systematically changing the volume fraction of the polymer fA and the Flory-Huggins interaction parameter χ.Comparing the phase diagram of AP molecule(Figure 1) with that of diblock copolymer [3],we find that although both of them include lamellar phase(L),gyroid phase(G),hexagonal arranged cylindrical phase(C),and body-centered cubic spherical phase(S),but the details are quite different.(1) The phase diagram of AP molecule is asymmetry due to the huge geometry difference between the particle and chain.Several morphologies,such as S,C,and G phase,disappear in fA < 0.5 region.(2) The region of 0.26 < fA < 0.325 is close packing region of spherical particles where excluded volume interaction dominates.fA < 0.26 is impossible in our model,therefore there no phase for fA < 0.26 region.(3) The order-disorder transition(ODT) line of AP molecule is shifted to lower values of χN when 0.325 < fA < 0.5,which means AP molecules have stronger tendency to phase separate than diblock copolymer.Moreover,the period size of the microphase morphologies of AP molecules is much smaller than diblock copolymer with the same fA and χN.(4) The C phase occupies a much wider region than diblock copolymer,and the phase regions of G and L phase shift towards lower fA.Our calculations not noly reproduce all self-assembled nanostructure of AP molecule and their sequence as observed in experiments [1],and also provide a full phase diagram and predict the liquid state of nanoparticles in particle-rich region due to benefit in translational entropy.Our theoretical method is of great potential to be extended to diverse,complicated systems containing rigid components and flexible components at the same time,such as bolaform-like molecule.The theoretical framework is promising to predict phase morphologies and phase diagram,provides a powerful strategy for studying novel nanostructure which can be applied in designing advanced materials.
Polymer-nanoparticle composites are becoming an intriguing and promising issue of organic-inorganic field.The nanoparticles substantially improve optical,electrical,and mechanical properties of polymer matrix,while the melt matrices,through microphase separation,provide a template for the distribution of nanoparticles.Recently,Cheng's group synthesized and studied linear polymer monotethered nanoparticles(namely AP molecule).They reported that AP molecules self-assemble into various nanostructures less than 10 nm.[1] In order to systematically investigate the self-assembly behavior of AP molecule consisting of a flexible linear homopolymer and a spherical nanoparticle in melt,we employ the combined self-consistent field theory and density functional theory(SCFT/DFT),which was first developed by Thompson et al [2].We studied the microphase separation of AP molecule by systematically changing the volume fraction of the polymer fA and the Flory-Huggins interaction parameter χ.Comparing the phase diagram of AP molecule(Figure 1) with that of diblock copolymer [3],we find that although both of them include lamellar phase(L),gyroid phase(G),hexagonal arranged cylindrical phase(C),and body-centered cubic spherical phase(S),but the details are quite different.(1) The phase diagram of AP molecule is asymmetry due to the huge geometry difference between the particle and chain.Several morphologies,such as S,C,and G phase,disappear in fA < 0.5 region.(2) The region of 0.26 < fA < 0.325 is close packing region of spherical particles where excluded volume interaction dominates.fA < 0.26 is impossible in our model,therefore there no phase for fA < 0.26 region.(3) The order-disorder transition(ODT) line of AP molecule is shifted to lower values of χN when 0.325 < fA < 0.5,which means AP molecules have stronger tendency to phase separate than diblock copolymer.Moreover,the period size of the microphase morphologies of AP molecules is much smaller than diblock copolymer with the same fA and χN.(4) The C phase occupies a much wider region than diblock copolymer,and the phase regions of G and L phase shift towards lower fA.Our calculations not noly reproduce all self-assembled nanostructure of AP molecule and their sequence as observed in experiments [1],and also provide a full phase diagram and predict the liquid state of nanoparticles in particle-rich region due to benefit in translational entropy.Our theoretical method is of great potential to be extended to diverse,complicated systems containing rigid components and flexible components at the same time,such as bolaform-like molecule.The theoretical framework is promising to predict phase morphologies and phase diagram,provides a powerful strategy for studying novel nanostructure which can be applied in designing advanced materials.
引文
[1]Yu,X.;Yue,K.;Hsieh,I.F.;Li,Y.;Dong,X.H.;Liu,C.;Xin,Y.;Wang,H.F.;Shi,A.C.;Newkome,G.R.;Ho,R.M.;Chen,E.Q.;Zhang,W.B.;Cheng,S.Z.D.Proceedings of the National Academy of Sciences.2013,110:10078.
[2]Thompson,R.B.;Ginzburg,V.V.;Matsen,M.W.;Balazs,A.C.Science.2001,292:2469.
[3]Matsen,M.W.;Bates,F.S.The Journal of Chemical Physics.1997,106:2436.
[2]Thompson,R.B.;Ginzburg,V.V.;Matsen,M.W.;Balazs,A.C.Science.2001,292:2469.
[3]Matsen,M.W.;Bates,F.S.The Journal of Chemical Physics.1997,106:2436.