Formation Of Hierarchical Structures Via Self-assembly Of Multiblock Copolymers

Hierarchical structures formed from polymeric materials have garnered considerable attention over the past decades because more than two length scales combing several properties and responding to multi external conditions make them attractive candidates for potential application in gas separation,drug delivery,and excellent sensors.Herein,we generated a design principle to craft a serial of hierarchical structures,including not only the one-dimensional(Lamellae)and two-dimensional(Cylinder)hierarchical structures,but also the three dimensional multi-continuous hierarchical network morphologies(Gyroid and O70)via the self-assembly of A(BC)2B multiblock terpolymers,and utilize the long A block and mid-thin BC block of multi-block copolymer to form the template and the mid-thin layer of hierarchical structures.The corresponding phase diagrams of these hierarchical structures at ?BcN=10 and 80 were calculated by using self-consistent field theory(SCFT),where three dimensional multi-continuous network morphology(Gyroid)was found to possess the larger compositional range at ?BCN=80.We continue to study the effect of ?BCN on the formation of hierarchical structures and constructed the corresponding phase diagrams.We observed the stable phase region of perpendicular lamellae at higher ?BCN,which is consistent with the experimental observation of perpendicular lamellae.In addition,hierarchical lamellae with less mid-thin layers was obtained as?BCN increases.In addition,to demonstrate the universality of this proposed design principle,we applied this design principle into the simple linear ABC system and a series of hierarchical structures(i.e.,S3,C3,G3,L3 and O703)was observed.For convenience,the hierarchical structures are labelled as Xk,where X indicates the conventional morphologies(such as L,G,C and S),and k indicates the number of internal B/C layers.The large phase regions of the hierarchical network structures(G3 and O703)were obtained in the left part of this phase diagram(fA<0.5).Furthermore,for the inverse design problem,we used ABC star-like block copolymer(existence of conjunction point of ABC block)to obtain the perpendicular morphologies,such as L?l,G?,O70? and C?.Therefore,the above results show that the design principle is universal.Finally,aim to increase widespread application of these multi-continuous network structures,we changed the fB/fC ratio to obtain a larger phase regions of these multi-continuous hierarchical network structures.We found that the phase regions of hierarchical network structures(G3 and O703)can be successfully adjusted by changing the fB/fC,and observed hierarchical network nanostructures with large phase regions at fB/fC=4 and 5 from the phase diagrams of the linear ABC system.In addition,we obtained the larger compositional ranges of hierarchical structures(i.e.,S3,C3,G3 and L3)in the left part of the phase diagram by changing fB/fC.Our calculated results have great guidance for the experimental observation of different hierarchical structures.