Cleanly Removable and Degradable Bio-Based Adhesive for Flexible Displays

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Engineering

Background:

• Conventional acrylic pressure-sensitive adhesives (PSAs) pose sustainability challenges in flexible display applications due to difficult removal and non-degradable backbones.
• Residue formation and the inability to recycle components hinder the environmental viability of current adhesive technologies.

Purpose of the Study:

• To develop novel acrylic PSA alternatives for foldable displays that are easily removable and degradable.
• To introduce ultraviolet (UV)-triggered debondability and lipoic acid analog-mediated degradation into PSA formulations.
• To enable visible-light curing for efficient processing.

Main Methods:

• Synthesized new acrylic PSAs incorporating lipoic acid ethyl ester (LpEt) and UV-cross-linkable benzophenone-functionalized acrylic monomers.
• Investigated the viscoelastic properties of the developed PSAs and compared them to conventional acrylic PSAs.
• Evaluated the clean removal, degradation into small molecular units using a green reductant, and monomer recovery under controlled conditions.

Main Results:

• The developed PSAs, containing 60 mol% LpEt and 3 mol% UV-cross-linkable monomers, demonstrated viscoelastic properties comparable to conventional acrylic PSAs.
• These novel PSAs enabled clean removal from substrates after use without significant residue.
• The adhesives were efficiently degraded into small molecular units or recovered as monomers, showcasing their recyclability.

Conclusions:

• The new acrylic PSAs offer a sustainable alternative to conventional adhesives for flexible display applications.
• The UV-triggered debondability and degradability facilitate component reuse and material recovery, promoting a circular economy.
• This approach provides a viable strategy for recycling valuable substrates from flexible display modules while enabling adhesive recovery.