Fatigue-resistant adhesion II: Swell tolerance

In a previous paper (Zhang et al., 2020), we have demonstrated an adhesive of high fatigue threshold ∼ $\sim$ 300 J/m 2 using an as-prepared hydrogel of long-chain polymer network . In most applications, however, hydrogel adhesives are in contact with water. The long-chain hydrogel swells and reduces the fatigue threshold. Here we demonstrate a type of swell-tolerant and fatigue-resistant hydrogel adhesive: a long-chain polymer network in topological entanglement with short-chain microgels . The short-chain microgels restrict swell, and the long-chain network retains the high fatigue threshold. After the hydrogel adhesives swell in water to equilibrium, the fatigue threshold is 61 J/m 2 ${}^2$ for an adhesive of a long-chain network without microgels, and is 262 J/m 2 for an adhesive of a long-chain network with microgels.