Spiral- and meridian-patterned spheres self-assembled from block copolymer/homopolymer binary systems

Core-shell particle formation via Co-assembly of AB diblock copolymers and nanoparticles in 3D soft confinement

Core-shell particle formation via co-assembly of AB diblock copolymers and nanoparticles in 3D soft confinement was studied using a simulated annealing method. Several sequences of soft confinement-induced core-shell particles were predicted as functions of the volume fraction of the nanoparticle to core-shell particles, the incompatibility between blocks, the volume fractions of A-blocks, the chain length of AB diblocks, the eccentricity of the nanoparticle, and the initial concentration of copolymers. Simulation results demonstrate that those factors are able to tune the morphology of the core-shell particles precisely. Calculated data indicate that the copolymer chain was located between a hard confinement wall composed of the nanoparticle and a soft confinement wall composed of solvents, and the arrangement direction of the copolymer chains was in a competitive equilibrium between the two. We anticipate that this work will be helpful and instructive for the preparation of polymer shells with different structures and shapes, as well as the study of self-assembly morphology of copolymers in a complex confinement systems.

Shell with Striped, Helical, and Bipolar Lamellae Structures from Soft Confinement-Induced Self-Assembly of AB Diblock Copolymers on a Nanocylinder

The soft confinement-induced self-assembly of AB diblock copolymers on a nanocylinder is studied via a simulated annealing method. The formation of multiple copolymer shells was predicted by varying the interfacial interaction, the size of confinement, and the height and diameter of the nanocylinder. The competition between solvent repulsion and nanocylinder attraction determined the degree of encapsulation of the copolymer shell. The formation of a helical copolymer shell was induced by the maximization of conformational entropy. The preferential distribution position of copolymers on anisotropic nanocylinder surfaces was induced by interfacial energy minimization. Our study contributes to the understanding of the formation mechanism of the helical structure in block copolymer aggregates and the fabrication of copolymer shells with predesigned morphologies.

Archimedean Spirals with Controllable Chirality: Disk Substrate-Mediated Solution Assembly of Rod-Coil Block Copolymers

Spirals are common in nature; however, they are rarely observed in polymer self-assembly systems, and the formation mechanism is not well understood. Herein, we report the formation of two-dimensional (2D) spiral patterns via microdisk substrate-mediated solution self-assembly of polypeptide-based rod-coil block copolymers. The spiral pattern consists of multiple strands assembled from the block copolymers, and two central points are observed. The spirals fit well with the Archimedean spiral model, and their chirality is dependent on the chirality of the polypeptide blocks. As revealed by a combination of experiments and theoretical simulations, these spirals are induced by an interplay of the parallel ordering tendency of the strands and circular confinement of the microdisks. This work presents the first example regarding substrate-mediated self-assembly of block copolymers into spirals. The gained information could not only enhance our understanding of natural spirals but also assist in both the controllable preparations and applications of spiral nanostructures.

Supramolecular Polymerization of Polymeric Nanorods Mediated by Block Copolymers

Introducing a second component is an effective way to manipulate polymerization behavior. However, this phenomenon has rarely been observed in colloidal systems, such as polymeric nanoparticles. Here, we report the supramolecular polymerization of polymeric nanorods mediated by block copolymers. Experimental observations and simulation results illustrate that block copolymers surround the polymeric nanorods and mainly concentrate around the two ends, leaving the hydrophobic side regions exposed. These polymeric nanorods connect in a side-by-side manner through hydrophobic interactions to form bundles. As polymerization progresses, the block copolymers gradually deposit onto the bundles and finally assemble into helical nanopatterns on the outermost surface, which terminates the polymerization. It is anticipated that this work could offer inspiration for a general strategy of controllable supramolecular polymerization.

From a single helix to a helical porous metalloenzyme catalyst based on temperature sensitive polyionic liquids

It is a challenging task to construct helical structures through the assembly of achiral polymers.