Dissipative Particle Dynamics Simulations Of The Self-assemble Morphologies Of Linear ABC Triblock Copolymers

The block copolymers can self-assemble to a variety of nanostructures with different shapes and sizes.These nanostructures have potential application in drug delivery,microelectronic materials,advanced plastics and so on.Therefor people have paid much attention to block copolymers.Linear ABC triblock copolymers consist of three different chemical blocks.Because of its simple topology and forming rich microstructure,the linear ABC triblock became a hot spot of research.e used Dissipative particle dynamics simulations to study the self-assembly behavior of linear ABC triblock copolymers in three different environment（solution,shear-rate,spherical confinement）.The main conclusions are as follows:1.In this work,for linear ABC terpolymers,their concentration-induced morphologies and morphological transitions are investigated with dissipative particle dynamics simulations.Firstly,several novel morphologies beyond those already known for dilute solutions,including the spherical core–shell–corona（CSC）micelle containing a small reverse CSC inside,the hexagonal packed cylinders in a lamella,the disk CSC micelle with a ring core,the multi-segment with a ring shell,and so on,were observed by varying the terpolymer concentration and the ratio of the three blocks.The reverse CSC structure explains the sources of experimental error in observation.Secondly,the increase of concentration generally resulted in the morphological transition from three-or two-dimensional（3D or 2D）to one-dimensional（1D）structures.Finally,the dynamic pathway of morphological formation is similar to that of ABC star miktoarm terpolymers,which has three steps,i.e.nucleation,coalescence and growth.Moreover,the qualitative analysis showed that interfacial tension plays a definite role in the formation of the final morphologies.2.In this work,shear flow is introduced to create 1D cylindrical micellar structures based on solution self-assembly of linear ABC terpolymers.The dissipative particle dynamics method is used to explore the whole morphological space.Firstly,7 spherical（0D）,10 cylindrical and 1 oblate spherical（1D）,5 lamella and 3 oblate cylindrical（2D）micellar structures are summarized from the total 315 morphologies.Secondly,when φ 00.1,l-BAC τ 00.1,the formation of all 1D cylindrical structure,l-ABC and l-BCA were mostly formed 1D cylindrical structure.In this work,several 1D cylindrical micelle structures the potential which can transform into single wall or double wall tube and cylindrical mixed micelles.Finally,the shear rate,the concentration and the solvophilic block length as 3 key factors of controlling the creation of multi-dimensional structures are given,which are important to the formation of 1D,2D and 0D structures,respectively.3.Here,dissipative particle dynamics simulations were used to explore the self-assemble behaviors of linear ABC triblock copolymers under rigid spherical confinements.First several unusual morphologies,such as multilayer onion,coupled helix,and stacked lamella,were distinguished from the total 210 simulations.Secondly,when special radius R060,interaction parameter αB（25）< αA（50）< αC（120）,symmetric B₂A₂C₂ and B₂C₂A₂ triblock copolymers formed the standard coreshell-corana structure;when R060,αB 0αA 0αC 0120,A₂B₂C₂ and B₂C₂A₂ formed layered structure,B₂A₂C₂ formed helix structure.Finally,the dynamics evolution of several typical aggregates was examined.