Stepwise Light-Induced Dual Compaction of Single-Chain Nanoparticles

Tanja K. Claus, Junliang Zhang, Liam Martin, Matthias Hartlieb, Hatice Mutlu, Sébastien Perrier, Guillaume Delaittre, Christopher Barner-Kowollik

Research output: Contribution to journalArticleResearchpeer-review

11 Citations (Scopus)

Abstract

A photochemical strategy for the sequential dual compaction of single polymer chains is introduced. Two photoreactive methacrylates, with side chains bearing either a phenacyl sulfide (PS) or an α-methylbenzaldehyde (photoenol, PE) moiety, are selectively incorporated by one-pot iterative reversible-addition fragmentation chain transfer copolymerization into the outer blocks of a well-defined poly(methyl methacrylate) based ABC triblock copolymer possessing a nonfunctional spacer block (Mn = 23 400 g mol−1, Đ = 1.2; ≈15 units of each photoreactive moieties of each type) as well as in model statistical copolymers bearing only one type of photoreactive unit. Upon UVA irradiation, PS and PE lead to highly reactive thioaldehydes and o-quinodimethanes, which rapidly react with dithiol and diacrylate linkers, respectively. The monomerfunctional copolymers are employed to establish the conditions for controlled intramolecular photo-crosslinking, which are subsequently applied to the bifunctional triblock copolymer. All compaction/folding experiments are monitored by size-exclusion chromatography and dynamic light scattering. The dual compaction consists of two events of dissimilar amplitude: the first folding step reveals a large reduction in hydrodynamic diameters, while the second compaction lead to a far less pronounced reduction of the single-chain nanoparticles size, consistent with the reduced degrees of freedom available after the first covalent compaction step.

Original languageEnglish
Article number1700264
Number of pages7
JournalMacromolecular Rapid Communications
Volume38
Issue number16
DOIs
Publication statusPublished - 1 Aug 2017

Keywords

  • block copolymers
  • photochemistry
  • RAFT polymerization
  • single chain folding
  • single chain nanoparticles (SCNPs)

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