Self‐assembly of triblock copolymers in the slits of neutral plates to form porous membranes and the pore size distribution: dissipative particle dynamics simulation

Abstract

The self-assembly morphology of triblock copolymers confined between the slits of neutral plates is investigated with the dissipative particle dynamics simulation method. A porous membrane structure with uniform pore size distribution is obtained. The pore size distribution shows linear laws affected by the concentration of the polymer solution, the hydrophilic and hydrophobic properties of the block as well as the polymer topology and slit thickness. When the concentration is in the range 0.4 to 0.7, the linear triblock copolymer forms continuous circular pores through self-assembly, and block components present a laterally layered texture. The ring triblock copolymer has no end groups and exhibits a unique self-assembly behavior. The cyclic triblock copolymer self-assembled in the slit is able to form an interpenetrating porous continuous structure, and the polymer film has a longitudinal layered structure. The star triblock copolymer has a more unique structure and can self-assemble into worm micelles with irregular pore structure and continuous interpenetration. In addition, the microphase separation structure of the triblock copolymer melt between the slits is studied. Generally, linear triblock copolymers generate longitudinal stripes, ring triblock copolymers form horizontal stripes and star triblock copolymers form a 'lattice' structure.