Superstrong Water-Based Supramolecular Adhesives Derived from Poly(vinyl alcohol)/Poly(acrylic acid) Complexes

It remains a great challenge for low-cost and mass fabrication of water-based adhesives with good adhesion performance. In this study, superstrong water-based supramolecular adhesives with long-term stability are fabricated by complexation of commercially available poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) in aqueous solution. The gel-like PVA/PAA adhesives can be conveniently injected and spread on targeted location for firm adhesion of various adherends such as glass, metals, and woods. The PVA/PAA adhesives achieve an adhesion strength of ∼5.9 MPa toward glass substrates and ∼14.3 MPa toward woods. The dried PVA/PAA adhesives are cross-linked with high density of hydrogen bonds between PVA and PAA as well as the physical entanglement of polymer chains, which determines the cohesive force of the adhesives. The adhesive surface has abundant noncomplexed hydroxyl and/or carboxylic acid groups, which can establish hydrogen bonds, coordination bonds, and van der Waals interactions with the surfaces of adherends to enable superstrong adhesion. The incorporation of Laponite RD (Lap) clays can further enhance the adhesion strength of the resultant PVA/PAA-Lap adhesives. As a result, the wooden bridge adhered by the PVA/PAA-Lap adhesive with an adhesive area of 50 mm × 50 mm can carry a weight of ∼179 kg without break.