Tuning And Designing The Self-assembly Of Surfactants By The Confinement Of Carbon Nanotube Arrays

Surfactants can self-assemble into well-ordered structures such as micelle,liquid crystal phase and vesicle.The property of self-assembled systems varies because of their difference in morphology,thus leading to extensive applications.Recently,tuning the self-assembly of surfactants,to obtain targeted morphology,has attracted great interests.However,the study of self-assembly is still in its infancy.This issue is still challenging because that our understanding on self-assembly is sparse,that our capability on tuning self-assembly is limited,and that the self-assembly morphology we got is simple.Obviously,insights into the self-assembly of surfactants are urgently needed.In this work,with the coarse-grained molecular dynamics approach,we carried out investigations on tuning and designing the self-assembly of surfactants by the confinement of carbon nanotube arrays.By studying self-assembled morphology with and without confinement,we found that the characteristic of the self-assembled structures cannot be changed by the confinement.At 50 wt %,surfactants self-assembled into rod,double helix,hexagonal phase,and “drill bit” with varying size and shape of confining space.These self-assembled structures maintain the characteristic of worm-like micelle,we call them the variants of worm-like micelle.Likewise,under confinement,the self-assembled structures of surfactants at 70 wt % maintain the characteristic of what we obtain with no confinement,the lamellar phase.The formation of lamellar phase variant under confinement was demonstrated to be an unfamiliar “successive self-assembly process”,that the bilayer fragments merge into complete structures one by one,from outside to inside.Inspired by the “successive self-assembly process”,we developed strategies to tune the self-assembly of lamellar phase variants,and we obtained polymorphic bilayer nano-tubes and nano-scrolls.In summary,we gave insights into the self-assembly of surfactants under confinement,which could benefit the development of self-assembly theories.We obtained series of novel self-assembled structures that is expected to facilitate the preparation of nano-materials.Furthermore,the strategies developed in this work to tune the self-assembly of surfactants could provide clues for further studies on tuning and designing self-assembly.