Ice-activated hydrogel suction cups enabling unprecedented adhesion

Abstract

Suction cups are widely used as switchable adhesion devices in manufacturing, robotic manipulation, and automated handling, yet their performance remains limited by insufficient suction force, leakage sensitivity, and poor adaptability to rough, cracked, porous, or irregular surfaces. Inspired by the familiar phenomenon in which a warm, water-rich tongue adheres strongly to ice, we report ice-activated hydrogel suction cups that exploit the phase transition of interfacial water into ice crystals to achieve strong and surface-adaptive adhesion. The hydrogel suction cups were fabricated by vat photopolymerization 3D printing and further programmed into different sizes and array architectures for adaptable adhesion and manipulation. At room temperature, the suction cups adhere through the combined effects of negative-pressure suction, water-mediated sealing, and liquid-bridge forces. Upon cooling, interfacial water freezes and grows into ice crystals within microscopic gaps, generating robust mechanical interlocking, while internal water crystallization stiffens the hydrogel body and reinforces the contact interface. This ice-activated mechanism enhances the adhesion strength to 1,719.67 kPa, which is approximately 100 times greater than that of polydimethylsiloxane suction cups and 55 times greater than that of hydrogel suction cups at room temperature. The suction cups exhibit robust adhesion on various substrates, including cracked or hole surfaces. Furthermore, integrated suction cup arrays facilitate the stable manipulation of objects with diverse geometries, weights, and frozen states, indicating potential applications in cold-chain handling, robotic pick-and-place operations, and automated logistics.

Keywords

Suction cups / surface-adaptive adhesion / 3D printing / mechanical interlocking / hydrogel

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