Light Stimuli-Responsive Degradable and Tough Polymeric Materials with Movable Cross-Links

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Engineering

Background:

• Sustainable societies require adhesive systems that are both strong and easily dismantled for substrate recovery and reuse.
• Cyclodextrins (CDs) can enhance adhesive strength through topological cross-linking.

Purpose of the Study:

• To develop a strong and dismantlable adhesive system using movable cross-links.
• To enable on-demand adhesion control via light stimulation.

Main Methods:

• Preparation of movable cross-linked poly(ethyl acrylate) (PEA-TAcγCD) incorporating polymerizable CDs and acid-degradable bonds (TAcγCDAAmMe).
• Utilizing photoacid generators to cleave cross-links upon light stimulation.
• Confirmation of degradation mechanism via mass spectrometry, tensile tests, and dynamic mechanical analysis.

Main Results:

• Successfully controlled mechanical properties by cleaving movable cross-links with light.
• Demonstrated light-induced cleavage of cross-linking points, altering mechanical properties and chain relaxation.
• Reduced adhesion strength upon light stimulation for both same and dissimilar substrates.

Conclusions:

• The light-responsive degradable elastomer functions as an easily dismantled, on-demand adhesion system.
• The acid-degradable bonds facilitate easy dismantling, enabling excellent adhesive properties and reusability.
• This technology contributes to resource disassembly, collection, and reuse, promoting a sustainable society.