Cleavage of Diblock Copolymer Brushes in a Selective Solvent and Fusion of Vesicles Self-Assembled by Pinned Micelles

Abstract

Lipid membrane fusion is a fundamental process in nature. In the fusion process two distinct bilayers merge the hydrophobic layers, and an interconnected structure is produced. In this research, the fusion of polymer membrane self-assembled by cleaved pinned micelles is investigated. Disulfide-tethered poly(tert-butyl acrylate-block-styrene) diblock copolymer brushes on the surfaces of silica particles were prepared by the "grafting to" or "grafting from" method. In acetone, the diblock copolymer brushes self-assemble into pinned micelles. Upon cleavage from the surfaces of the silica particles with n-tributylphosphine, the pinned micelles self-assemble into vesicles. In the meanwhile, thiol groups at the ends of the block copolymer brushes were produced in the cleavage reaction. Because of the oxidation of the thiol groups and the formation of the disulfide bonds, the vesicle structures are fused into bigger hollow structures and fiber-like structures. The further fusion of the fiber-like structures results in precipitation of the polymer from the solution.

From Self-Assembled Monolayers to Coatings: Advances in the Synthesis and Nanobio Applications of Polymer Brushes

“…Examples include the use of crosslinked or multiple-point grafted poly(glycidyl methacrylate) (PGMA) thin coatings or epoxy terminated silane SAMs to attach amine-or acid-terminated polymers [62][63][64][65][66][67][68], a reductive alkylation reaction between amine-functionalized surface and aldehyde-terminated polymers to form an imine bond which is subsequently reduced [69,70], Au-S bond formation between thiol-terminated polymer and Au surface [71,72], thiol-disulfide exchange reaction using thiol-terminated block copolymers to prepare for cleavable polymer brushes on silica particles [73,74], an amidation reaction of N-hydroxysuccinamde protected carboxylic acid terminated polymers and amine functionalized SAMs on surface [75], Diels-Alder ligation reaction between cyclopentadiene and maleimide [76], and a condensation reaction between silane-terminated polymers and silanol groups on an oxide surface [77].…”

In situ fabrication of PHEMA–BSA core–corona biohybrid particles

“…The disulfides are readily reduced to thiols within a reducing environment resulting in cleavage of the disulfide bonds. 47,48 Disulfides can be cleaved efficiently by DTT. 48 In this research we investigated the change in the morphology of the core-corona particles upon addition of DTT.…”

Surface Reconstruction by a Coassembly Approach

“…[5] Then anostructures exert significant influence on the surface properties of the matrixes.F or example,t reatment of the mixed polymer brushes with different solvents lead to changes in the surface roughness and wetting behaviors. [8] Them orphology and size of the surface micelles are determined by many factors,i ncluding the interactions between solvent and brushes,t he block lengths,a nd the volume percentage of each block. [7] Cast from ag ood solvent, the block copolymer brushes have vertical microphase separation.…”