ORGS5-1379
Advanced Adhesives by Supramolecular Ionic Polymerization
Topic
GS5. Graduate Student Oral Session V: Sustainable Polymers and Circular Materials
When and Where
Sep 28, 2026
14:36 - 14:48
Room 105
Session Chairs
Taehoo CHANG
Taejun EOM
Chae Bin KIM
Presenter(s)
Hanyu Liang (The University of Tokyo)
Co-Author(s)
Abstract
Advanced adhesives must combine strong bonding with easy, clean debonding, yet these requirements are inherently difficult to reconcile. High strength usually depends on irreversible interfacial interactions or densely cross-linked networks, whereas readily debondable adhesives often suffer from poor mechanical durability, particularly under humid conditions.
Here, we developed a supramolecular adhesive, SAGuTU, by mixing the guanidinium–thiourea monomer GuTU with sodium hexametaphosphate (SHMP) in water. Multivalent salt-bridge formation induced spontaneous liquid–liquid phase separation, producing a condensed adhesive phase. SAGuTU exhibited lap-shear strengths of up to 18.6 MPa on glass and 8.1 MPa on wood, comparable to commercial epoxy adhesive. A glass joint with a bonded area of only 1.2 cm² supported a 20 kg load. The adhesive also showed excellent humidity resistance, with almost no strength loss after 96 h at 70% relative humidity and retention of approximately 11 MPa after 96 h at 80% relative humidity. Thiourea groups act as hydrophobic hydrogen-bonding motifs, suppressing moisture-induced weakening.
Despite its high strength and humidity resistance, SAGuTU was readily debonded by saline water mist, unlike commercial epoxy adhesive. Dynamic light scattering showed that GuTU/SHMP aggregates had an average diameter of approximately 420 nm and remained stable after dilution with deionized water, whereas saline solution reduced the size to approximately 1.2 nm. This result confirms that salt ions disrupt guanidinium–phosphate salt bridges and dissociate the supramolecular ionic network into molecular species. Consequently, SAGuTU enables clean debonding without obvious residue or substrate damage. This adhesive therefore integrates ultrastrong adhesion, long-term humidity resistance, and salt-triggered debonding within a single recyclable supramolecular system.
Here, we developed a supramolecular adhesive, SAGuTU, by mixing the guanidinium–thiourea monomer GuTU with sodium hexametaphosphate (SHMP) in water. Multivalent salt-bridge formation induced spontaneous liquid–liquid phase separation, producing a condensed adhesive phase. SAGuTU exhibited lap-shear strengths of up to 18.6 MPa on glass and 8.1 MPa on wood, comparable to commercial epoxy adhesive. A glass joint with a bonded area of only 1.2 cm² supported a 20 kg load. The adhesive also showed excellent humidity resistance, with almost no strength loss after 96 h at 70% relative humidity and retention of approximately 11 MPa after 96 h at 80% relative humidity. Thiourea groups act as hydrophobic hydrogen-bonding motifs, suppressing moisture-induced weakening.
Despite its high strength and humidity resistance, SAGuTU was readily debonded by saline water mist, unlike commercial epoxy adhesive. Dynamic light scattering showed that GuTU/SHMP aggregates had an average diameter of approximately 420 nm and remained stable after dilution with deionized water, whereas saline solution reduced the size to approximately 1.2 nm. This result confirms that salt ions disrupt guanidinium–phosphate salt bridges and dissociate the supramolecular ionic network into molecular species. Consequently, SAGuTU enables clean debonding without obvious residue or substrate damage. This adhesive therefore integrates ultrastrong adhesion, long-term humidity resistance, and salt-triggered debonding within a single recyclable supramolecular system.
