溶剂对嵌段共聚物AB/均聚物C共混体系增容效果的模拟研究  

A Simulation Study of Enhancing the Compatibility in Block Copolymer AB/Homopolymer C Blends by Solvents

作　　者：刘志瑶 王铮 尹玉华 蒋润 李宝会 Zhi-yao Liu;Zheng Wang;Yu-hua Yin;Run Jiang;Bao-hui Li(Key Laboratory of Functional Polymer Materials of Ministry of Education,School of Physics,Nankai University,Tianjin 300071)

机构地区：[1]南开大学物理科学学院教育部功能高分子材料重点实验室

出　　处：《高分子学报》2019年第11期1229-1237,共9页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号21574071,21774066,21528401,20925414,91227121);教育部创新团队发展计划(项目号IRT1257);高等学校学科创新引智111计划(项目号B16027)资助项目

摘　　要：采用模拟退火方法研究了两嵌段共聚物AB/均聚物C共混体系在溶液中的相行为.关注于C与A/B为排斥作用时溶剂对它们的增容作用.考察了溶剂的加入量(以聚合物链节的浓度Φ表征)、加入C的体积分数f_c、C与AB的链长比X、C与AB排斥作用、溶剂S与C吸引作用强度等对体系相容性及组装行为的影响.构建了作为Φ和f_c的函数的形态相图.研究表明,当X小于0.5,且C与A/B间的排斥作用不是很强时,加入强亲A/C的溶剂能够提高体系的相容性.并获得了层状相、连通相、层中柱状相、核壳柱状相等相结构,其中层中柱状相是纯两嵌段共聚物体系中没有的结构.在高Φ值的体系中,C分布在A/B的界面上;在低Φ值的体系中,C分布在A相区中.研究表明,X越小,C与A、B嵌段的接触数越大,均聚物越容易与两嵌段共聚物相容;X越大,加入少量的均聚物体系就发生宏观相分离,且增加B/C间的排斥作用会降低体系的相容性.体系形态结构的转变以及微相分离到宏观相分离的转变都是体系的能量与熵之间竞争的结果.溶液体系中宏观相分离与熔体时的不同,溶液中部分C链节在AB的界面上以减小AB的接触,而熔体时全部的C链节均与AB宏观相分离.The phase behavior of diblock copolymer AB/homopolymer C blends in solution was studied by simulated annealing method. The study was focused on the compatibilization between the homopolymer and the copolymer with repulsive interactions due to the addition of solvent. We investigated the amount of solvent(characterized by the concentration of the polymer segments Φ), the volume fraction fc of the homopolymer C, the ratio of homopolymer chain length to the copolymer chain length X, the repulsion between C and A or B segments, εAC and εBC, and the attraction between solvent and C on the phase behavior of the blending system. We built phase diagrams in the space of Φ and fc at different X. Studies have shown that when X is less than 0.5, and the values of εAC and εBC are not very large, the addition of solvent strongly selective to A and C segments can improve the compatibility of the system. In solution, lamellae, gyroids, cylinders in layers, core-shell cylinders and cylindrical structures are formed. Moreover, the structure of cylinders in layers has not been observed in the neat diblock copolymer system. C-segments are distributed at the interfaces between A/B domains at high Φregion, while they are inside the A domain at low Φ region. Short homopolymer chains are easily compatible with diblock copolymers. Macroscopic phase separation has taken place in long homopolymer chains even with a small amount of homopolymer added. Moreover, increasing the values of εAC and εBC will reduce the compatibility of the system. The transformation between different phases and that from microphase separation to macrophase separation are the results of the competition between the energy and entropy of the system. The macrophase separation in the solution system is different from that in the melt system. Some C-segments are at the interface of AB domains to reduce the contact between A and B segments in the solution system, while all C-segments are separated from the AB domains in the melts.

关 键 词：嵌段共聚物 均聚物 共混 溶剂 增容 

分 类 号：TQ317[化学工程—高聚物工业]