Microfibres and macroscopic films from the coordination-driven hierarchical self-assembly of cylindrical micelles

Abstract

Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials. However, the assembly of these structural units is generally limited to the use of amphiphilic interactions. Here we report a simple, reversible coordination-driven hierarchical self-assembly strategy for the preparation of micron-scale fibres and macroscopic films based on monodisperse cylindrical block copolymer micelles. Coordination of Pd(0) metal centres to phosphine ligands immobilized within the soluble coronas of block copolymer micelles is found to induce intermicelle crosslinking, affording stable linear fibres comprised of micelle subunits in a staggered arrangement. The mean length of the fibres can be varied by altering the micelle concentration, reaction stoichiometry or aspect ratio of the micelle building blocks. Furthermore, the fibres aggregate on drying to form robust, self-supporting macroscopic micelle-based thin films with useful mechanical properties that are analogous to crosslinked polymer networks, but on a longer length scale.

Bicomponent Block Copolymers Derived from One or More Random Copolymers as an Alternative Route to Controllable Phase Behavior

“…More complex nanoscale morphologies, such as the bicontinuous gyroid, twisted helices, a Frank‐Kasper σ phase, and coexisting lamellae+spheres, have also been reported to form in neat copolymers, and many of these signature nanostructures, as well as others (e.g., bicontinuous microemulsions), have likewise been observed in block copolymers containing one or more homopolymers or solvents . In some cases, self‐assembly can be controlled and directed in block‐selective solvents by, for example, crystallization and/or chemical coordination to yield highly anisotropic nanoscale objects such as cylinders measuring more than 10 μm in length. Because of their inherent ability to self‐assemble, block copolymers have driven the development of numerous (nano)technologies ranging from biomedical and optical devices to nanotemplated surfaces and various separation/functional membranes .…”

Recent progress in block copolymer crystallization

“…By fabricating hierarchical coating structures, this expands the generality and scope of template‐assisted synthesis to build advanced hierarchical materials while also having precise morphology. Using coordination chemistry, microfibers and macroscopic films were fabricated by assembling poly(methylvinylsiloxane)‐ b ‐PFS (PMVS‐ b ‐PFS) with 35 mol% diphenylphosphine functionalization of the pendant vinyl group on the PMVS . Palladium was added to complex with the phosphine, and it showed the ability to complex with more than one micelle in a directed way where the ends were attached to form large microfibers.…”

“…In most cases, CDSA was used to form worm‐like micellar structures with crystalline cores of either PE or PFS . While the current focus of CDSA research is related to controlled micelle growth and hierarchical assembly, triblock terpolymers provide another opportunity to tailor the corona of the micelle to form “patchy” morphologies on the micelle surface . For diblock copolymers, this was achieved by mixing two copolymers .…”

Two‐Dimensional Seeded Self‐Assembly of a Complex Hierarchical Perylene‐Based Heterostructure

“…The utilization of living self‐assembly methods to fabricate complex architectures with precisely controlled dimensions has attracted much attention in the last decade . Particularly, crystallization‐driven living self‐assembly of block copolymers (BCPs) that have been pioneered by Manners et al.…”