Living Supramolecular Polymerisation of Perylene Diimide Amphiphiles by Seeded Growth under Kinetic Control.

The controlled solution self-assembly of an amphiphilic perylene diimide (PDI), with a hydrophobic perylene core and hydrophilic imide substituents with polydisperse oligo(ethylene glycol) (OEG) tethers is presented. It was possible, by a seeded-growth mechanism, to form colloidally stable, one-dimensional fibres with controllable lengths (from 400 to 1700 nm) and low dispersities (1.19-1.29) via a living supramolecular polymerisation process. Under the solvent conditions used, it was found that molecularly dissolved material (unimer) was present in samples of the fibre-like supramolecular assemblies. The free unimer may be present in a conformationally derived kinetically trapped state and/or may represent a more soluble PDI fraction with longer hydrophilic tethers. Significantly, it was also possible to form segmented supramolecular block copolymers by the addition of PDI unimer to chemically distinct PDI seeds, yielding fibres with controlled lengths. These results represent a significant advance in the ability to form PDI-based supramolecular polymers with precisely controlled lengths and architectures.

1D Self-Assembly and Ice Recrystallization Inhibition Activity of Antifreeze Glycopeptide-Functionalized Perylene Bisimides.

Antifreeze glycoproteins (AFGPs) are polymeric natural products that have drawn considerable interest in diverse research fields owing to their potent ice recrystallization inhibition (IRI) activity. Self-assembled materials have emerged as a promising class of biomimetic ice growth inhibitor, yet the development of AFGP-based supramolecular materials that emulate the aggregative behavior of AFGPs have not yet been reported. This work reports the first example of the 1D self-assembly and IRI activity of AFGP-functionalized perylene bisimides (AFGP-PBIs). Glycopeptide-functionalized PBIs underwent 1D self-assembly in water and showed modest IRI activity, which could be tuned through substitution of the PBI core. This work presents essential proof-of-principle for the development of novel IRIs as potential supramolecular cryoprotectants and glycoprotein mimics.

Programmable Assembly of π-Conjugated Polymers.

π-Conjugated polymers have numerous applications due to their advantageous optoelectronic and mechanical properties. These properties depend intrinsically on polymer ordering, including crystallinity, orientation, morphology, domain size, and π-π interactions. Programming, or deliberately controlling the composition and ordering of π-conjugated polymers by well-defined inputs, is a key facet in the development of organic electronics. Here, π-conjugated programming is described at each stage of material development, stressing the links between each programming mode. Covalent programming is performed during polymer synthesis such that complex architectures can be constructed, which direct polymer assembly by governing polymer orientation, π-π interactions, and morphological length-scales. Solution programming is performed in a solvated state as polymers dissolve, aggregate, crystallize, or react in solution. Solid-state programming occurs in the solid state and is governed by polymer crystallization, domain segregation, or gelation. Recent progress in programming across these stages is examined, highlighting order-dependent features and assembly techniques that are unique to π-conjugated polymers. This should serve as a guide for delineating the many ways of directing π-conjugated polymer assembly to control ordering, structure, and function, enabling the further development of organic electronics.

Oxidation promoted self-assembly of π-conjugated polymers.

Self-assembly is an attractive strategy for organizing molecules into ordered structures that can span multiple length scales. Crystallization Driven Self-Assembly (CDSA) involves a block copolymer with a crystallizable core-forming block and an amorphous corona-forming block that aggregate into micelles with a crystalline core in solvents that are selective for the corona block. CDSA requires core- and corona-forming blocks with very different solubilities. This hinders its use for the self-assembly of purely π-conjugated block copolymers since blocks with desirable optoelectronic properties tend to have similar solubilities. Further, this approach is not readily reversible, precluding stimulus-responsive assembly and disassembly. Here, we demonstrate that selective oxidative doping of one block of a fully π-conjugated block copolymer promotes the self-assembly of redox-responsive micelles. Heteroatom substitution in polychalcogenophenes enables the modulation of the intrinsic polymer oxidation potential. We show that oxidized micelles with a narrow size distribution form spontaneously and disassemble in response to a chemical reductant. This method expands the scope of π-conjugated polymers that can undergo controlled self-assembly and introduces reversible, redox-responsive self-assembly of π-conjugated polymers.

Surface Patterning of Uniform 2D Platelet Block Comicelles via Coronal Chain Collapse.

The formation of colloids with anisotropically patterned surfaces is of growing interest for the creation of hierarchical structures and the templating of nanoparticles. We have recently shown that well-defined two-dimensional platelets with low areal dispersities can be formed by the seeded growth of a blend of homopolymers and block copolymers. Herein we form rectangular platelets containing two block copolymers with different coronal chemistries. On addition of a solvent that is only able to solvate the corona of one block, we were able to form colloidally stable micelles with patterned surfaces via coronal collapse. Scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy and atomic force microscopy were employed to provide information on the structure and size of the patches decorating the micelle surfaces.

Crystallization-Driven Self-Assembly of Metallo-Polyelectrolyte Block Copolymers with a Polycaprolactone Core-Forming Segment.

We report crystallization-driven self-assembly (CDSA) of metallo-polyelectrolyte block copolymers that contain cationic polycobaltocenium in the corona-forming block and crystallizable polycaprolactone (PCL) as the core-forming block. Dictated by electrostatic interactions originating from the cationic metalloblock and crystallization of the PCL, these amphiphilic block copolymers self-assembled into two-dimensional platelet nanostructures in polar protic solvents. The 2D morphologies can be varied from elongated hexagons to diamonds, and their stability to fragmentation was found to be dependent on the ionic strength of the solution.