多分散性对两亲性两嵌段共聚物在选择性溶剂中自组装行为影响的Monte Carlo模拟

采用Monte Carlo模拟方法研究了多分散性AB两亲性两嵌段共聚物在选择性溶剂中的自组装行为.模拟结果表明,嵌段共聚物的多分散性对体系在选择性溶剂中自组装所形成的胶束形貌结构有很大影响.当AB两嵌段共聚物的多分散系数由1.0增加至1.4时,体系中自组装所形成的胶束将会发生由囊泡到片层直至球状的一系列形态转变.通过统...

EFFECT OF POLYDISPERSITY ON THE SELF-ASSEMBLY OF AMPHIPHILIC DIBLOCK COPOLYMER IN A SELECTIVE SOLVENT:A MONTE CARLO STUDY

The effect of polydispersity on the self-assembly of amphiphilic diblock copolymer in a selective solvent was studied by means of Monte Carlo simulation.The polydisperse diblock copolymer system was constructed via the mixing of three amphiphilic diblock copolymer chains different in lengthi,.e.,A2B2,A2B6 and A2B10.The simulation results show that the micelle morphologies formed by AB diblock copolymers in a selective solvent changed from vesicle to lamellae,then to spheres with an increase in polydispersity index(PDI) from 1.0 to 1.4.Through the analysis of the variations of the number and fractions of free single chains with the increase of PDI in each system,it is found that the number of short chains(i.e.A2B2) which aggregate into micelles increased with an increasing PDI.Meanwhilet,he self-assembly processes of diblock copolymers with different PDI in a selective solvent reveal that the increasing number of short chains can increase the surface area of the micellesl,eading to a disadvantage for the fusion between small micelles during the self-assembly.The increase of the surface area of micelles is the main reason of the morphological transition from large-sized vesicles to small-sized spheres when the PDI is increased.These simulation results indicate that the micelle morphologies and their mutual transitions in a selective solvent can be tuned by the control of the polydispersity of AB diblock copolymers.