Water-assisted strong underwater adhesion via interfacial water removal and self-adaptive gelation

Abstract

In nearly all cases of underwater adhesion, water molecules typically act as a destroyer. Thus, removing interfacial water from the substrate surfaces is essential for forming super-strong underwater adhesion. However, current methods mainly rely on physical means to dislodge interfacial water, such as absorption, hydrophobic repulsion, or extrusion, which are inefficient in removing obstinate hydrated water at contact interface, resulting in poor adhesion. Herein, we present a unique means of reversing the role of water to assist in realizing a self-strengthening liquid underwater adhesive (SLU-adhesive) that can effectively remove water at contact interface. This is achieved through multiscale physical–chemical coupling methods across millimeter to molecular levels and self-adaptive strengthening of the cohesion during underwater operations. As a result, strong adhesion over 1,600 kPa (compared to ~100 to 1,000 kPa in current state of the art) can be achieved on various materials, including inorganic metal and organic plastic materials, without preloading in different environments such as pure water, a wide range of pH solutions (pH = 3 to 11), and seawater. Intriguingly, SLU-adhesive/photothermal nanoparticles (carbon nanotubes) hybrid materials can significantly reduce the time required for complete curing from 24 h to 40 min using near-infrared laser radiation due to unique thermal-response of the chemical reaction rate. The excellent adhesion property and self-adaptive adhesion procedure allow SLU-adhesive materials to demonstrate great potential for broad applications in underwater sand stabilization, underwater repair, and even adhesion failure detection as a self-reporting adhesive. This concept of “water helper” has potential to advance underwater adhesion and manufacturing strategies.

A Nature‐Derived, Hetero‐Structured, Pro‐Healing Bioadhesive Patch for High‐Performance Sealing of Wet Tissues

“…To verify the complete removal ability of interfacial water by our SSAD-Patch, we further employed sum frequency generation (SFG) spectroscopy to detect its interfacial dehydration behavior (Figure S12, Supporting Information). [43,44] As shown in Figure S13, Supporting Information, the plasma-treated quartz surface exhibited substantial water signals as revealed by the two large ─OH stretching-contributed peaks observed (3200 and 3400 cm −1 ) (Figure S13A, Supporting Information). As the interfacial water was removed by the SSAD-Patch applied on the quartz surface, the overall intensities of the SFG signals at 3200 and 3400 cm −1 peaks decreased dramatically within 10 s to completely undetectable (Figure S13B, Supporting Information), which further proved the complete removal of the interface water molecules.…”

Design Strategy for Water/Temperature-Resistant Acrylic-Based Adhesives with Green Recall

“…[4][5][6]8 In addition, the organic solvents used in the synthesis of adhesives are harmful to the environment. [1][2][3][8][9][10]12 The adhesive designed in this work has the advantages of low cost, simple process, no organic solvents, and reversible adhesion (Figure 1a). 13 Based on publicly available commercial information, the adhesive strength ranges of acrylic-based, polyurethane-based, and epoxy-based adhesives are 0.3−31, 3−25, and 2−38 MPa, respectively (Figure 1b).…”

“…We utilize the cost of laboratory raw materials per unit of adhesive strength and quality as the parameter to evaluate the cost of adhesives and consider the total number of raw materials and synthesis steps as the parameter to assess the complexity of preparation. Although some high-performance adhesives have been developed, their high manufacturing costs and complex synthesis routes limit their application prospects. ,,− Irreversible adhesion can limit reuse and result in unnecessary loss. − , In addition, the organic solvents used in the synthesis of adhesives are harmful to the environment. − ,− , The adhesive designed in this work has the advantages of low cost, simple process, no organic solvents, and reversible adhesion (Figure a) . Based on publicly available commercial information, the adhesive strength ranges of acrylic-based, polyurethane-based, and epoxy-based adhesives are 0.3–31, 3–25, and 2–38 MPa, respectively (Figure b). , Based on last year’s trade data from major industrialized countries, the price ranges for acrylic-, polyurethane-, and epoxy-based materials are US$2092–3391, US$3033–6010, and US$3622–7008 per ton, respectively (Figure b) .…”

“…Researchers are striving to solve this problem by focusing on durability, recyclability, , the use of renewable resources, and other aspects. Some new advances in the two-dimensional distribution diagram in Figure a − are discussed. We utilize the cost of laboratory raw materials per unit of adhesive strength and quality as the parameter to evaluate the cost of adhesives and consider the total number of raw materials and synthesis steps as the parameter to assess the complexity of preparation.…”

Self‐Contained Underwater Adhesion and Informational Labeling Enabled by Arene‐Functionalized Polymeric Ionogels

“…[6,41,42] Several emerging strategies have been explored including: introduction of noncanonical building blocks (i.e., ionic, zwitterionic, and aromatic units) in supramolecules, polymers, and polyelectrolytes, [43][44][45][46][47][48][49][50][51] design of supramolecular, interpenetrating, and double networks in multicomponent hydrogels and ionogels, [3,37,50,[52][53][54][55] and the use of hygroscopic compounds and physical removal for interfacial dehydration. [56][57][58] Despite the notable progress, a few challenges persist in the pursuit of next-generation underwater adhesives, which can be generalized as follows. i) Adhesive hydrogels and ionogels typically experience swelling in humid environments due to their high hydrophilicity and ionic osmotic pressure of dissociated counterions, resulting in surface hydration, fragile structures, and subpar underwater adhesion.…”