Supramolecular Micellization of Diblock Copolymer Mixtures Mediated by Hydrogen Bonding for the Observation of Separated Coil and Chain Aggregation in Common Solvents

Abstract

This paper describes a new approach towards preparing self‐assembled hydrogen‐bonded complexes that have vesicle and patched spherical structures from two species of block copolymer in non‐selective solvents. The assembly of vesicles from the intermolecular complex formed after mixing polystyrene‐block‐poly(4‐vinyl phenol) (PS‐b‐PVPh) with poly(methyl methacrylate)‐block‐poly(4‐vinylpyridine) (PMMA‐b‐P4VP) in tetrahydrofuran (THF) is driven by strong hydrogen bonding between the complementary binding sites on the PVPh and P4VP blocks. In contrast, well‐defined patched spherical micelles form after blending PS‐b‐PVPh with PMMA‐b‐P4VP in N,N‐dimethylformamide (DMF): weaker hydrogen bonds form between the PVPh and P4VP blocks in DMF, relative to those in THF, which results in the formation of spherical micelles that have compartmentalized coronas that consist of PS and PMMA blocks.magnified image

Hierarchical Assembly of Complex Block Copolymer Nanoparticles into Multicompartment Superstructures through Tunable Interparticle Associations

“…These types of particles can also be made with mixtures of different block copolymers and variation of the ratio of molecules in the assembly mixture. Moreover, without being covalently linked in the same molecular backbone, components in the mixture are responsive to various external stimuli such as solvent exchange, [ 40 ] changes in temperature, pH, [ 41 ] ionic strength, [ 23 ] and assembly kinetics. [ 26 ] Also, the components are dynamic enough to demix internally into compartments of diverse sizes and geometries depending on the type and amount of block copolymers in the original mixture.…”

Electrostatic hierarchical co-assembly in aqueous solutions of two oppositely charged double hydrophilic diblock copolymers

“…[47][48][49][50]) or corona-forming blocks (see for example Refs. [51][52][53]). Finally, we would like to point out that self-consistent field calculations on bimodal (bidisperse) brushes (polymer brushes consisting of two types of polymers differing only in size; that is, identical in chemical composition) have demonstrated that patchy brushes can arise merely as a result of a distinct difference in polymer block length [54]; that is, without any chemical incompatibility as all polymer chains were of identical chemical composition.…”

Mixed micelles self-assembled from block copolymers for drug delivery

“…The research done so far mostly involves the micellization of block copolymers in solvents other than pure aqueous medium [87][88][89] or the use of copolymers (in block form or otherwise) with and without mixing with homopolymers in organic solvents [16,90,91]. Copolymers and homopolymers were also mixed in organic solvents to produce vesicles mediated by the hydrogenbonding [91][92][93][94]. These mixed micelle systems were not customized for drug delivery purposes but merely studied to explore their behaviors in different milieus.…”

“…FTIR spectra are useful in indicating hydrogen bonds between specific hydrogen bond acceptors and donors in the different blocks of the copolymers when there is a shift of peak frequency of bands to a lower wavenumber. For example, the hydrogen bonds between polystyrene-block-poly(4-vinyl phenol) (PS-b-PVPh) and poly(methylmethacrylate)-block-poly(4-vinylpyridine) (PMMA-b-P4VP) were studied by FTIR in THF and DMF [91,94]. Information extracted from the spectra such as the difference in the shift of the wavenumbers of hydroxyl bands of P4VP after mixing with PS-b-PVPh then alluded to the difference in strength of the H-bonding between the PVPh and P4VP blocks in different solvents.…”