复合物中环状接枝纳米粒子表面高分子结构及动力学的计算机模拟研究
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- 英文论文题名：Computer simulation of annularly grafted nanoparticles in polymer nanocomposites:the interface structure and dynamics
- 论文作者：施睿 ; 于林秀子 ; 钱虎军 ; 吕中元
- 英文论文作者：Rui Shi ; Lin-Xiuzi Yu ; Hu-Jun Qian ; State Key Laboratory of Supramolecular Structure and Materials ; Institute of Theoretical Chemistry ; Jilin University
- 年：2016
- 作者机构：吉林大学理论化学研究所超分子结构与材料国家重点实验室;
- 论文关键词：高分子纳米复合物 ; 接枝纳米粒子 ; 环状接枝 ; 计算机模拟
- 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：TB383.1;O631.1
- 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：266k
- 原文格式：D
- 会议级别：全国
摘要
纳米粒子高分子复合物由于具有优于高分子本身的性能而应用广泛[1-3],因此,纳米粒子如何影响复合物宏观性质是近年来材料科学中重要的问题。Mackay等人[4]提出,在高分子体系中加入交联高分子纳米粒子可以大幅降低高分子复合物粘度,这与通常无机纳米粒子产生的粘度增高效应不同[5]。为深入研究此类现象,我们设计了与交联高分子纳米粒子相似的无自由链末端的环状接枝纳米粒子的粗粒化模型进行模拟研究,对环状接枝纳米粒子表面界面层的高分子链结构、动力学性质进行了分析。通过对熔体链不同长度链段的切向以及径向回转半径的分析[6],可以看出,随着接枝密度的增大,切向和径向回转半径收敛的距离略有外推,这意味着增加接枝密度,纳米粒子对链段影响略有增大,图中虚线代表切向回转半径,可以看出,尽管链段长度增大,近距离处切向回转半径依然大于径向回转半径,由此可知,熔体链在靠近纳米粒子附近时,受纳米粒子影响有较强的取向作用;该作用在链段长度较小时消失于距离纳米粒子表面2倍链段回转半径处,随着链段的增大,纳米粒子的影响范围变小,在距纳米粒子表面约1.5倍链段回转半径处收敛。同时,我们对与纳米粒子尺寸相近的链段(长50)的松弛行为进行了分析,可以看出,在一定接枝密度、接枝链长的条件下,纳米粒子对体系中链段松弛行为影响十分显著(Fig.1b),环状接枝纳米粒子与交联纳米粒子体现出相似的加速链段松弛的行为。同时,在距离纳米粒子表面不同距离情况下,近处链段松弛加快,这与硬无机纳米粒子行为存在明显的不同。
Understanding the mechanism of how the macro physical properties(e.g.viscosity,refractive index or thermal conductivity) of polymer nanocomposites(PNCs) were influenced by nanoparticles(NPs) is a recurring challenge in material science.Mackey et al.suggested that adding chemically identical polymer cross-linked nanoparticles in related polymer matrix could marvelously reduce the viscosity of resulting PNC.This phenomenon is,unlike PNCs containing hard-core inorganic NPs,which usually results in an increase of viscosity.In this poster,we will report an analog to this cross-linked NP by annularly grafted hard-sphere NP with short ligands.Using this model,we analyzed both the chain configurational and the dynamical properties of micro NP-polymer interface.The results show that(1) with short annularly grafted chains,the thickness of the interface defined by the influence rang of the NP on the melt chain Rg tensor are analyzed.We show that the relative interface thickness was reduced from 2Rg for short segments to 1.5Rg for long ones.(2) The chain segment relaxation was significantly boosted at some certain conditions.(3) The segment relaxation in vicinity of the NP can be accelerated by the annularly grafted chains.
Understanding the mechanism of how the macro physical properties(e.g.viscosity,refractive index or thermal conductivity) of polymer nanocomposites(PNCs) were influenced by nanoparticles(NPs) is a recurring challenge in material science.Mackey et al.suggested that adding chemically identical polymer cross-linked nanoparticles in related polymer matrix could marvelously reduce the viscosity of resulting PNC.This phenomenon is,unlike PNCs containing hard-core inorganic NPs,which usually results in an increase of viscosity.In this poster,we will report an analog to this cross-linked NP by annularly grafted hard-sphere NP with short ligands.Using this model,we analyzed both the chain configurational and the dynamical properties of micro NP-polymer interface.The results show that(1) with short annularly grafted chains,the thickness of the interface defined by the influence rang of the NP on the melt chain Rg tensor are analyzed.We show that the relative interface thickness was reduced from 2Rg for short segments to 1.5Rg for long ones.(2) The chain segment relaxation was significantly boosted at some certain conditions.(3) The segment relaxation in vicinity of the NP can be accelerated by the annularly grafted chains.
引文
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[2]1.Kumar,S.K.,Jouault,N.,Benicewicz,B.&Neely,T.Macromolecules 2013,46,3199–3214
[3]1.Kim,J.,Yang,H.&Green,P.F.Langmuir 2012,28,9735–9741
[4]Mackay,M.E.;Dao,T.;Tuteja,A.;Ho,D.L.;van Horn,B.;Kim,H.;Hawker C.J.Nat.Mater.2003,2,762
[5]Choi,J.;Hore,M.J.A.;Clarke,N.;Winey,K.I.;and Composto,R.J.Macromolecules,2014,47,2404.
[6]Ndoro T.V.M;Voyiatzis E.;Ghanbair A.;Theodorou D.N.;Bohm M.C.;Müller-Plathe F.[J].Macromolecules2012,45:171-179.