On-Demand Reversible Hydrogel Adhesive: Visible-Light Bonding and Rapid UV-Triggered Debonding

This invention is a novel hydrogel glue system that utilizes dual-wavelength light to provide independent control over both adhesion and detachment. It polymerizes under visible light to form a robust bond and undergoes rapid ultraviolet (UV)-triggered cleavage for effortless, non-invasive removal.

Description

The adhesive system is composed of a polyacrylic acid (PAA) matrix reinforced by a specialized poly(ethylene glycol) diacrylate (PEGDA) crosslinker that incorporates an ortho-nitrobenzyl (ONB) moiety. To initiate bonding, the liquid precursor is exposed to visible light (470 nm). This triggers a free-radical polymerization process facilitated by a camphorquinone photo-initiator, that transforms the liquid into a strong, solid adhesive network. The innovative aspect of this technology lies in the "orthogonal" design of the ONB crosslinker, which is stable under visible light but highly sensitive to UV light (365 nm). When debonding is required, UV exposure causes the ONB groups to cleave, systematically breaking the internal crosslinks of the hydrogel. This targeted molecular degradation leads to a rapid softening of the material and a dramatic loss of adhesive strength, allowing the substrates to be separated easily without mechanical stress or residue.

Applications

- Biomedical Devices: Temporary fixation of wearable sensors or medical equipment to the skin.
- Temporary Wound Closure: Use as a tissue glue for non-invasive wound management and painless reopening for clinical inspection.
- Recyclable Materials: Facilitating the easy disassembly of bonded components in manufacturing to improve material recovery and recycling.
- Electronics Assembly: Temporary bonding of delicate components during manufacturing or testing phases.
- Industrial Temporary Fixation: Applications in manufacturing where parts require strong temporary attachment before final assembly.

Advantages

- On-Demand Debonding: Enables fast and easy removal of the adhesive using a simple LED light trigger.
- Precise Control: Offers spatial and temporal precision over both the bonding and debonding processes.
- Strong Performance: Maintains high initial adhesion strength (~200 kPa) comparable to non-reversible hydrogel glues.
- Rapid Response: Achieves a fourfold reduction in adhesion strength in as little as 90 seconds under UV irradiation.
- Minimal Substrate Stress: Provides a non-contact removal method that avoids the mechanical strain or high temperatures typically required by traditional reversible adhesives.

Invention Readiness

The technology is currently in the proof-of-concept stage with established in vitro data. Extensive laboratory testing has characterized the synthesis of the ONB-PEGDA crosslinker, the kinetics of its photodegradation, and its performance on various substrates including glass, rubber, steel, and skin. Experimental data confirms that UV exposure can reduce the storage modulus by over 80% and the overall adhesive strength by more than 70% within minutes. Further studies are planned to evaluate the technology's performance in ex vivo and in vivo settings, specifically focusing on its application as a non-invasive tissue glue for wound closure.

IP Status

Patent Pending

Related Publication(s)

Wang, Huaming, et al. "Dual‐Wavelength Responsive Hydrogel Glue with Visible‐Light Bonding and UV‐Triggered Debonding via Ortho‐Nitrobenzyl Cleavage." Advanced Science 12.40 (2025): e07809. https://doi.org/10.1002/advs.202507809