College of Materials, Xiamen University, Xiamen 361005, People's Republic of China.
Fujian Provincial Key Laboratory of Fire Retardant Materials, Xiamen University, Xiamen 361005, People's Republic of China.
Sci Robot. 2021 Apr 14;6(53). doi: 10.1126/scirobotics.abe1858.
Although there have been notable advances in adhesive materials, the ability to program attaching and detaching behavior in these materials remains a challenge. Here, we report a borate ester polymer hydrogel that can rapidly switch between adhesive and nonadhesive states in response to a mild electrical stimulus (voltages between 3.0 and 4.5 V). This behavior is achieved by controlling the exposure and shielding of the catechol group through water electrolysis-induced reversible cleavage and reformation of the borate ester moiety. By switching the electric field direction, the hydrogel can repeatedly attach to and detach from various surfaces with a response time as low as 1 s. This programmable attaching/detaching strategy provides an alternative approach for robot climbing. The hydrogel is simply pasted onto the moving parts of climbing robots without complicated engineering and morphological designs. Using our hydrogel as feet and wheels, the tethered walking robots and wheeled robots can climb on both vertical and inverted conductive substrates (i.e., moving upside down) such as stainless steel and copper. Our study establishes an effective route for the design of smart polymer adhesives that are applicable in intelligent devices and an electrochemical strategy to regulate the adhesion.
尽管在黏附材料方面已经取得了显著的进展，但在这些材料中编程黏附和解离行为的能力仍然是一个挑战。在这里，我们报告了一种硼酸酯聚合物水凝胶，它可以在温和的电刺激（3.0 和 4.5 V 之间的电压）下迅速在黏附状态和非黏附状态之间切换。这种行为是通过控制儿茶酚基团的暴露和屏蔽来实现的，这是通过水诱导的硼酸酯部分的可逆断裂和重新形成来实现的。通过切换电场方向，水凝胶可以以低至 1 s 的响应时间，反复地黏附和脱离各种表面。这种可编程的黏附/脱离策略为机器人攀爬提供了一种替代方法。该水凝胶只需粘贴到攀爬机器人的运动部件上，无需复杂的工程和形态设计。使用我们的水凝胶作为脚和轮子， tethered 步行机器人和轮式机器人可以在垂直和倒置的导电基板（即倒置）上攀爬，例如不锈钢和铜。我们的研究为设计智能聚合物黏附剂提供了一种有效的途径，这些黏附剂适用于智能设备和电化学策略来调节黏附力。
