在平行板受限条件下AB两嵌段共聚物/纳米粒子复合物自组装行为的Monte Carlo模拟

Monte Carlo Simulation on Self-assembly of AB Diblock Copolymers/Nanoparticles Complex Confined in Parallel Walls

采用Monte Carlo模拟方法研究了在平行板受限条件下A_(15)B_5非对称两嵌段共聚物与纳米粒子复合物的自组装行为,其中平行板对多组分嵌段A具有吸引相互作用.模拟结果表明,纳米粒子在两嵌段共聚物/纳米粒子复合物中的体积分数、嵌段共聚物不同嵌段与纳米粒子间的相互作用均对体系在平行板受限条件下的形貌结构及纳米粒子在体系中的分布有重要影响.当平行板间距一定时,未添加纳米粒子的A_(15)B_5非对称两嵌段共聚物中的A嵌段被吸附在平行板上形成层状相,而B嵌段则在平行板中形成六角堆积穿孔层状结构.加入与A嵌段不相容而与B嵌段相容的纳米粒子后,增加了纳米粒子与B嵌段的相容性,有利于保持B嵌段所形成的穿孔结构及孔洞尺寸,同时纳米粒子能够均匀地分散在B相区中.当引入的纳米粒子与A和B两嵌段均不相容时,降低纳米粒子与嵌段共聚物的不相容性同样有利于维持体系的穿孔结构.当纳米粒子与AB两嵌段共聚物间的排斥作用微弱时,即使含量较高,纳米粒子也不聚集,并且均匀分布在A相区与B相区的交界处.

The self-assembly behavior of the A15B5 asymmetric diblock copolymers/nanoparticles composite confined in parallelwalls which attract A blocks was studied using Monte Carlo simulation. The simulation results indicates that the volume fraction of the nanoparticles in diblock copolymers/nanoparticles composite and the interactions between nanoparticles and each blocks are crucial to the self-assembled structures formed by diblock copolymers/nanoparticles composite and the distribution of nanoparticles. When the distance between the two parallel walls keep constant,A15B5 asymmetric diblock copolymers can self-assemble into parallel layers in which the mid-layer formed by B blocks are hexagonally perforated. When the nanoparticles which are incompatible with blocks A,while compatible with blocks B are added into the system,increasing the attractive interaction between nanoparticles and blocks B can effectively maintain the hexagonally perforated structure and the pore size in the layer. At this time,the nanoparticles are homogenously distributed in the domain formed by blocks B. However,when the nanoparticles which are incompatible with both blocks are added into the system,a decrease in the repulsive interaction between nanoparticles and block copolymers can benefit for maintaining the hexagonally perforated structure. In addition,when the interaction between nanoparticles and block copolymers is rather weak,the nanoparticles cannot aggregate even if the volume fraction of the nanoparticles is very large,and the nanoparticles homogenously disperse in the interface between A and B phases.