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Stepwise Light-Induced Dual Compaction of Single-Chain Nanoparticles
Tanja K Claus1,2, Junliang Zhang3, Liam Martin3
1Macromolecular Architectures, Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76131, Karlsruhe, Germany.
Macromolecular Rapid Communications
|July 5, 2017
Summary
This study introduces a photochemical method for sequentially compacting single polymer chains. Using specific photoreactive units, polymers undergo two distinct folding steps, significantly reducing their size.
Area of Science:
- Polymer Chemistry
- Photochemistry
- Materials Science
Background:
- Controlled polymer architecture is crucial for advanced material properties.
- Photochemical crosslinking offers precise spatial and temporal control over polymer modification.
- Sequential compaction of single polymer chains remains a challenge in macromolecular science.
Purpose of the Study:
- To develop a photochemical strategy for sequential dual compaction of single polymer chains.
- To synthesize well-defined ABC triblock copolymers with photoreactive outer blocks.
- To investigate intramolecular photo-crosslinking for controlled polymer folding.
Main Methods:
- One-pot iterative reversible-addition fragmentation chain transfer (RAFT) copolymerization to synthesize ABC triblock copolymers.
- Incorporation of phenacyl sulfide (PS) and α-methylbenzaldehyde (photoenol, PE) photoreactive moieties.
- UVA irradiation to trigger photochemical reactions and subsequent crosslinking with dithiol and diacrylate linkers.
- Monitoring compaction using size-exclusion chromatography (SEC) and dynamic light scattering (DLS).
Main Results:
- Successfully synthesized ABC triblock copolymers and statistical copolymers with precisely placed photoreactive units.
- Demonstrated sequential dual intramolecular photo-crosslinking upon UVA irradiation.
- Observed two distinct compaction events with dissimilar amplitude, indicated by significant hydrodynamic diameter reduction in the first step and a lesser reduction in the second.
- Correlated compaction behavior with the polymer's degree of freedom after initial folding.
Conclusions:
- The developed photochemical strategy enables controlled, sequential dual compaction of single polymer chains.
- The method allows for the creation of single-chain nanoparticles with tunable sizes through stepwise folding.
- This approach offers a novel pathway for designing complex macromolecular architectures with potential applications in nanotechnology and drug delivery.
Keywords:
RAFT polymerizationblock copolymersphotochemistrysingle chain foldingsingle chain nanoparticles (SCNPs)
