Automated Search Strategy for Novel Ordered Structures of Block Copolymers.

Block copolymers with different architectures can possibly generate innumerable stable or metastable structures and thus provide an irreplaceable platform for theoretically exploring novel structures. Self-consistent field theory (SCFT) is a powerful tool to predict the ordered structures of block copolymers; however, it is sensitively dependent on its initial condition. Here we propose to use multiple symmetry-adapted basis functions to generate the initial conditions of SCFT and then apply Bayesian optimization to search for ordered structures by navigating the coefficient space of these basis functions.

Hierarchically engineered nanostructures from compositionally anisotropic molecular building blocks.

The inability to synthesize hierarchical structures with independently tailored nanoscale and mesoscale features limits the discovery of next-generation multifunctional materials. Here we present a predictable molecular self-assembly strategy to craft nanostructured materials with a variety of phase-in-phase hierarchical morphologies. The compositionally anisotropic building blocks employed in the assembly process are formed by multicomponent graft block copolymers containing sequence-defined side chains.

Single Gyroid Self-Assembled by Linear BABAB Pentablock Copolymer.

Although the double-gyroid (DG) structure has been commonly formed from the self-assembly of block copolymers, the single-gyroid (SG) structure is rarely reported. Moreover, the SG structure even shows better performance than DG in some optical applications. How to prepare the SG structure has become an attractive but challenging topic.

Synergistic Effect of Stretched Bridging Block and Released Packing Frustration Leads to Exotic Nanostructures.

The self-assembly of amphiphilic macromolecules into various mesocrystals has attracted abiding interest. Although many interesting mesocrystals have been achieved, mesocrystals of a low coordination number (CN) such as simple cubic are rarely reported. Here we purposely design an AB-type multiblock copolymer to target exotic spherical phases of low CNs.

Stabilizing Phases of Block Copolymers with Gigantic Spheres via Designed Chain Architectures.

It is generally believed that the spherical domains self-assembled from -type block copolymers are composed of the minority blocks with a volume fraction of < 1/2. Breaking this generic rule so that the spherical domains are formed by the majority blocks ( > 1/2) requires mechanisms to drastically expand the stable region of spherical packing phases. Self-consistent field theory predicts that dendron-like -type block copolymers, composed of - 1 generations of blocks connected with the outermost generation of blocks, exhibit a stable region of spherical packing phases extending to ∼ 0.

Regulate the Stability of Gyroids of ABC-Type Multiblock Copolymers by Controlling the Packing Frustration.

We propose to regulate the stability of gyroids of ABC-type multiblock copolymers by controlling the packing frustration of majority-component B-blocks. Accordingly, we investigate the self-assembly behaviors of the BABCB linear terpolymer with a variable length ratio τ of the middle B-block relative to the total B-blocks using self-consistent field theory. It is observed that the gyroid region exhibits a maximal width with respect to τ, which is attributed by the nonmonotonical change of the packing frustration of three B-blocks in the morphology of discrete domains, for example, cylinders.

Tetragonal phase of cylinders self-assembled from binary blends of AB diblock and (A'B) star copolymers.

The phase behavior of binary blends composed of AB diblock and (A'B) star copolymers is studied using the polymeric self-consistent field theory, focusing on the formation and stability of the stable tetragonal phase of cylinders. In general, cylindrical domains self-assembled from AB-type block copolymers are packed into a hexagonal array, although a tetragonal array of cylinders could be more favourable for lithography applications in microelectronics. The polymer blends are designed such that there is an attractive interaction between the A and A' blocks, which increases the compatibility between the two copolymers and thus suppresses the macroscopic phase separation of the blends.

Stabilizing the Frank-Kasper Phases via Binary Blends of Diblock Copolymers.

The emergence of the complex Frank-Kasper phases from binary mixtures of diblock copolymers is studied using the self-consistent field theory. The relative stability of different ordered phases, including the Frank-Kasper σ and 15 phases containing nonspherical minority domains with different sizes, is examined by a comparison of their free energy. The resulting phase diagrams reveal that the σ phase occupies a large region in the phase space of the system.

Chiral selection of single helix formed by diblock copolymers confined in nanopores.

Chiral selection has attracted tremendous attention from the scientific communities, especially from biologists, due to the mysterious origin of homochirality in life. The self-assembly of achiral block copolymers confined in nanopores offers a simple but useful model of forming helical structures, where the helical structures possess random chirality selection, i.e.