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Published on: October 31, 2019
Light-Controlled Topology Switching Enables Continuous Modulation of Thermally Induced Phase Behavior in Polymer
Zhuoheng Yu1, Jie Zhang1, Jun Liu1
1School of Chemistry and Chemical Engineering, Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
ACS Macro Letters
|June 30, 2026
Summary
This study introduces a light-responsive poly(ethylene glycol) (PEG) system for reversible polymer topology switching. This innovation allows dynamic control over polymer solution phase behavior and thermoresponsive properties.
Area of Science:
- Polymer Chemistry
- Materials Science
- Physical Chemistry
Background:
- Dynamic control over polymer solution phase behavior, particularly with real-time reversibility, presents significant scientific challenges.
- Thermoresponsive polymers are crucial in various applications, but precise, non-invasive regulation of their phase transitions remains difficult.
Purpose of the Study:
- To develop a novel light-responsive poly(ethylene glycol) (PEG) system enabling reversible switching between linear and cyclic polymer topologies.
- To demonstrate the continuous modulation of thermally induced phase transitions in aqueous polymer solutions through topology interconversion.
- To investigate the impact of polymer topology on solution thermodynamics and aggregation behavior.
Main Methods:
- Functionalization of linear poly(ethylene glycol) (PEG) with styrylpyrene end groups for light-induced [2 + 2] photocycloaddition.
- Utilizing visible light to promote intramolecular cyclization, forming cyclic PEG, and UV irradiation to revert to linear PEG.
- Characterizing the reversible topology switching and quantifying the resulting changes in cloud point temperature and aggregation behavior.
Main Results:
- Achieved efficient and reversible switching between linear and cyclic PEG topologies using visible and UV light.
- Demonstrated continuous tuning of the cyclic/linear polymer ratio, leading to modulation of the cloud point temperature over a wide range (37–65 °C).
- Observed enhanced aggregation in linear PEG due to end-group interactions, contrasted with suppressed aggregation in cyclic PEG owing to topological constraints.
Conclusions:
- Topology switching is established as a noninvasive strategy for dynamically regulating polymer solution thermodynamics.
- Polymer topology is identified as a critical and tunable parameter for controlling thermoresponsive behavior.
- This work offers new possibilities for designing advanced smart materials with precisely controlled phase transition properties.
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