Simply Formulated Dry Pressure-Sensitive Adhesives for Substrate-Independent Underwater Adhesion

Abstract

Due to the long-standing challenge to realize underwater adhesion, there are a few commercially available underwater pressure-sensitive adhesives (PSAs), which are, however, ubiquitously used for dry adhesion. Herein, a dry underwater PSA is developed on the basis of a simple, low-cost, and easily commercial formulation, which only involves the copolymerization of butyl acrylate (BA) and acrylic acid (AA). By tuning the ratios between the hydrophobic BA unit and H-bonding AA unit, we optimize the viscoelastic properties of the PSA to maximize the underwater adhesion performance. The PSA exhibits high underwater bonding strength (e.g., >115 kPa) for diverse substrates (e.g., glass, metals, plastics), at the preload (e.g., 250 kPa) easily accessed by finger pressing. Moreover, the PSA exhibits dry adhesion capability, rendering it conveniently adhered to a backing material to form an underwater adhesive tape. The dry PSA can well-maintain its underwater adhesion performance even after long-term storage in air or incubation in water.

A dynamic polyurea network with exceptional creep resistance

“…Therefore, A-PU gathers both the advantages of thermosets (especially excellent chemical and creep resistance) and the reprocessability of thermoplastic polymers. Furthermore, we found that this material can be used as strong adhesive with an adhesion strength of about 14 MPa mainly due to abundant hydrogen bonds, 34 and the adhesive also displays outstanding creep resistance and long-term solvent resistance. Based on the above-mentioned properties, the adhesive stands a good chance to be used in automobile manufacture industry, construction industry, or even aerospace industry.…”

Natural-silk-inspired design provides ultra-tough biobased structural adhesives with supercold tolerance

“…It is reasonable that the realization of lowtemperature tolerant adhesion behaviors in these supramolecular polymer systems is crucially dependent on the cohesive polymeric structures and segmental motions. [31][32][33] However, these different properties are not easily achieved in traditional supramolecular adhesive systems due to their conicting nature. 10,34 Although multifunctional supramolecular adhesives have been extensively exploited in recent years, to date, it is still a lasting challenge to design elastomer adhesives that combine high adhesion performance and reliable tolerance toward ultracold temperature.…”

Multifunctional Underwater Adhesive Film Enabled by a Single-Component Poly(ionic liquid)

“…Recently, much effort has been devoted to exploring advanced wet adhesives with high yield, robust adhesion, and multiple functions. Among different types of wet adhesives, supramolecular adhesives are particularly attractive due to their flexibility in chemical structural design, reusability, and controllable architectures. − Nevertheless, only a few studies on supramolecular adhesives, which were constructed by selected oligomers and/or polymers, have been reported, and most of them show limited adhesion capability under wet/underwater conditions. Developing suitable supramolecular systems for wet adhesion is of great significance but extremely challenging, because the supramolecular system should simultaneously meet the following strict requirements to achieve good wet adhesion performance: (1) supramolecular materials should have strong attractive interactions with the target substrate across aqueous media; (2) the supramolecular system is expected to expel the confined water layer between adhesive and target substrates to achieve intimate contact; (3) the supramolecular system is expected to automatically spread over the target surface in water without being diluted; (4) the supramolecular system should have reasonable solidification kinetics, which ensures both the ease of application and the strong cohesion strength of the adhesive.…”