Synthesis of High Molecular Weight Comb Block Copolymers and Their Assembly into Ordered Morphologies in the Solid State

Abstract

This Article describes a simple two-step synthesis of comb block copolymers with molecular weights exceeding 1,000,000 g mol(-1) and their assembly into ordered morphologies in the solid state. This work is exciting because these polymers assembled into morphologies with domain sizes exceeding 100 nm and, in some examples, 200 nm without the use of additives. These materials reflected selected wavelengths of visible light, and these wavelengths could be affected by swelling with methylene chloride vapor. A comparison between the structures of comb block copolymers and linear block copolymers is presented with a discussion of important parameters affecting their assembly in the solid state. This Article will first describe the synthesis of comb block copolymers using ring opening metathesis polymerization and atom transfer radical polymerization and their subsequent characterization. The comb block copolymers, backbone polymers, and polystyrene arms were all characterized independent of each other and had low polydispersities. The comb block copolymers were assembled by dissolving in methylene chloride and allowing the solvent to evaporate. After thermal annealing, the polymers were characterized by scanning electron and optical microscopy. These polymers assembled into spherical, lamellar, and cylindrical arrays with domain sizes from 132 to 258 nm. This work extends the molecular architectures of polymers that can be assembled in the solid state, the molecular weights of block copolymers that were assembled, and the domain sizes that can be realized without the use of additives.

Structure, function, self-assembly, and applications of bottlebrush copolymers

“…7A). Subsequently, the same group found similar selfassembly behaviour in a series of brush-linear diblock copolymers 98,99 . Scanning electron microscopy (SEM) and UV-Vis absorbance analysis revealed the formation of large block copolymer domains ranging in size from 100 -300 nm with morphologies in the lamellar, cylindrical, or spherical phase depending on the relative block lengths.…”

Design, Synthesis, and Self-Assembly of Polymers with Tailored Graft Distributions

“…Graft polymers display many unique properties compared to their linear analogues, such as extended chain conformations, [5][6][7][8] increased entanglement molecular weights, [9][10][11][12] and architecturedependent rheological behavior. [13][14][15][16] Recent studies have harnessed these properties in a wide variety of applications in photonics, [17][18][19] drug delivery, [20][21][22] transport, [23][24] and thermoplastics. [25][26] Continued progress in synthetic command over polymer architecture enables further studies of structure-property relationships and inspires new potential applications.…”

Rapid self-assembly of brush block copolymers to photonic crystals

“…This simple architecture forms the basis for a variety of modern optical elements, including filters, antireflection coatings, and resonant cavities. Recently, very high molecular weight block copolymers have enabled chemically and mechanically tunable PCs at visible frequencies (4,(6)(7)(8), providing a versatile platform for the development of unique nanostructures with exciting possibilities for functional, moldable, and paintable PCs.…”