The Self-assembly Behavior Of Multicomponent Polymers Induced By Nanorods And External Filed

Block copolymers have become a hot topic in soft matter field because of their unique structure.Previous studies have found that the self-assembly of diblock copolymers has formed a variety of periodic ordered structures.For example:layered structure（parallel layered,vertical layered,tilted layered）,cylindrical structure,spherical structure,etc.It is a good control method to prepare functional nanomaterials by doping nanoparticles in block copolymer or applying external field.Firstly,the self-assembly behavior of block copolymer/homopolymer/nanorods induced by nanorods was studied.According to fixing the asymmetric degree of block copolymer AB,f _A-f _B=0.05,four structures were obtained with the change of the concentration of homopolymer C and the number of nanorods:SI-R structure（sea-island structure,incomplete stratification within the island）,SI structure（sea-island structure,complete stratification within the island）,L-T structure（disordered tilted lamellar structure,AB phase incomplete stratification）,L-TO structure（ordered tilted lamellar structure,AB phase alternating stratification）.For further understanding,we studied the effect of the number of nanorods on the composite system when the concentration of component C was0.25 with different b1 values.Then we further analyzed the phase diagram of the composite system with the change of the rod number and the asymmetry degree.Then we discussed the influence of rod length,wetting strength,the rod-rod interaction and the long-range correlation strength on the phase behavior of the composite system.Secondly,the oscillating shear field was applied to the two diblock copolymers to control the phase structure.The simulation results show that when f _AB/CD=7/3 and the shear amplitude was 0.02,with the increasing of shear frequency,the CD phase underwent the phase transformation of concentric ring structure—parallel layered structure within the ring—concentric ring structure—parallel layered structure,and the AB phase underwent the phase transformation of oblique layered structure-parallel layered structure-vertical layered structure.In addition,we analyzed the growth curve and morphology evolution process,and found that it was consistent with the previous phase transition.Then we discussed the effect of b₂₂ on the microscopic phase separation.Finally,we changed the composition ratio of the two diblock copolymers,the effects of different shear frequencies and amplitudes on the self-assembly behavior of the composite system were studied,and the growth curve and morphology evolution of the composite system were analyzed.Finally,we made a brief summary.And we hope the computer simulation results will be helpful to the theory and related experiments in the future.