Stimulus-responsive block copolymer nano-objects and hydrogels via dynamic covalent chemistry. Issue 35 (8th August 2017)

• Record Type: Journal Article
• Authors: Deng, Renhua; Ning, Yin; Jones, Elizabeth R.; Cunningham, Victoria J.; Penfold, Nicholas J. W.; Armes, Steven P.
• Is Part Of: Polymer chemistry. Volume 8:Issue 35(2017)
• Page Start: 5374
• Page End: 5380
• Publication Date: 2017-08-08
• Subjects: Polymers -- Periodicals; Macromolecules -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1039/c7py01242j
• Languages: English
• ISSNs: 1759-9954

Abstract

Abstract : Dynamic covalent chemistry can be used to induce reversible morphological transitions for block copolymer nano-objects in mildly alkaline solution. Abstract : Herein we demonstrate that dynamic covalent chemistry can be used to induce reversible morphological transitions in block copolymer nano-objects and hydrogels. Poly(glycerol monomethacrylate)–poly(2-hydroxypropyl methacrylate) (PGMA–PHPMA) diblock copolymer nano-objects (vesicles or worms) were prepared via polymerization-induced self-assembly. Addition of 4-carboxyphenylboronic acid (CPBA) leads to the formation of phenylboronate ester bonds with the 1, 2-diol pendent groups on the hydrophilic PGMA stabilizer chains; such binding causes a subtle reduction in the packing parameter, which in turn induces either vesicle-to-worm or worm-to-sphere transitions. Moreover, CPBA binding is pH-dependent, so reversible transitions can be achieved by switching the solution pH, with relatively high copolymer concentrations leading to associated (de)gelation. This distinguishes these new physical hydrogels from the covalently cross-linked gels prepared using dynamic covalent chemistry reported in the literature.