A hydrogel-based, strong adhesive with fast and reversible thermally activated bonding for use in various environments.

Adhesives are ubiquitous in daily life and can be found everywhere from construction and industrial applications to electronic assemblies to medical uses such as wound closure and medical device attachment. Adhesives are primarily divided into two classes—strong and irreversible adhesives, which result in waste and destructive delamination, or weak and reversible adhesives, which lack strength for various applications. There is, therefore, a need for adhesives that provide both strong and reversible bonding.

The adhesive bonds both strongly and reversibly quickly hardening to achieve super-glue-like attachment while still allowing for removal, if necessary. Additionally, the glue is biocompatible and usable in wet environments, which makes it ideal for many medical applications.

The adhesive consists of a hydrogel material mixed with a polymer (N-isopropylacrylamide, NiPAM). At room temperature, the material is soft and malleable, but when the temperature rises to body temperature, the polymer becomes water insoluble and causes physical binding in the hydrogel. This results in the formation of an interpenetrating network between the two materials, and the adhesive quickly becomes stiff and strong. This response is reversible; when the temperature returns to below body temperature the material becomes soft and malleable again.

• Fast adhesion time (~2 minutes)
• Strong adhesion (up to 900 N/cm²)
• Reversible (soft at 20°C, cured at 37°C)
• Biocompatible
• Compatible with wet environments
• Suitable for medical applications