The application of hydrogels has recently expanded markedly owning to the achievement of strong adhesion. In characterizing adhesion, a hydrogel is often subjected to 90-degree peel, during which the peel force increases, maximizes then drops to a plateau at steady state. The steady state peel force determines the adhesion toughness. The maximum peel force determines a debonding resistance that is higher than adhesion toughness, which, however, has been largely unheeded before. This paper studies the mechanics pertaining to the maximum peel force and describes a method to enhance the debonding resistance by invoking the large-scale bridging mechanism. We achieve, by varying the bending stiffness, an increment of debonding resistance from ∼ 185 N/m to ∼ 856 N/m for a single-network polyacrylamide hydrogel and from 486 N/m to 2054 N/m for a double-network Ca-alginate/PAAm hydrogel on a glass substrate. The increment of debonding resistance depends on the thickness of the hydrogel and the bending stiffness of the backing. As a proof-of-concept deployment of the method, we fabricate a bilayer consisting of a passive hydrogel 2 and a responsive (PAAc/Ca(Ac)₂) hydrogel 1. The PAAc/Ca(Ac)₂ hydrogel is soft at 25 °C (E ∼ 0.5 MPa) but stiffens dramatically at 75 °C (E ∼ 100 MPa), serving as the stiff backing to elicit large-scale bridging mechanism to improve the debonding resistance by one order of magnitude. We establish a theoretical model to probe the peel behaviors based on the cohesive-zone model and solve the resultant boundary value problem numerically. Theoretical predications satisfactorily agree with experimental results. We discuss the importance of maximum peel force and the potentials of large-scale bridging mechanism in improving debonding resistance for soft materials.

由于实现了强粘附力，水凝胶的应用最近显着扩大。在表征粘附力时，水凝胶通常要进行 90 度剥离，在此期间剥离力增加，达到最大值，然后在稳定状态下下降到平台。稳态剥离力决定了粘合韧性。最大剥离力决定了比粘合韧性更高的抗剥离性，然而，这在很大程度上之前被忽视了。本文研究了与最大剥离力有关的力学，并描述了一种通过调用大规模桥接机制来提高抗剥离性的方法。我们通过改变弯曲刚度来实现，在玻璃基板上，单网络聚丙烯酰胺水凝胶的剥离阻力从 185 N/m 增加到 856 N/m，双网络海藻酸钙/PAAm 水凝胶从 486 N/m 增加到 2054 N/m . 剥离阻力的增加取决于水凝胶的厚度和背衬的弯曲刚度。作为该方法的概念验证部署，我们制造了一个由被动水凝胶 2 和响应 (PAAc/Ca(Ac)₂ ) 水凝胶 1. PAAc/Ca(Ac) ₂水凝胶在 25 °C ( E ∼ 0.5 MPa) 时柔软，但在 75 °C ( E ∼ 100 MPa) 时显着变硬，作为刚性背衬，引发大规模桥接机制将抗剥离性提高一个数量级。我们建立了一个理论模型来探讨基于内聚区模型的剥离行为，并数值求解合成边界值问题。理论预测与实验结果一致。我们讨论了最大剥离力的重要性和大规模桥接机制在提高软材料抗剥离性方面的潜力。