For highly conformable and universal transport devices, bioinspired dry adhesion systems with reversible molecular attractions (e.g., van der Waals forces, capillarity, or suction stress) between the engaged surfaces have recently become favorable for various dry/wet processes in flexible devices and medical applications. In addition, many efforts have been made for switchable attachments of such adhesives by employing costly sophisticated systems such as mechanically deformable chucks, UVradiating components, or fluidic channels. In this work, we propose a simple electrothermally actuating transport device based on an octopus-inspired microsphereembedded sucker (OMS). The adhesive with microsphere-embedded suckers offers enhanced adhesion on dry/wet surfaces, in accordance with investigation of the geometric and materials parameters of the novel suction architecture for maximizing adhesion interactions. Inspired by muscle actuation of octopus tentacles, we laminate the electrothermally reactive poly(3,4-ethylenedioxy thiophene):poly(styrenesulfonic acid) (PEDOT:PSS) layer on the backside of the OMS adhesive patch. By controlling inputs of electrical energy, our assembled actuator may actively expand and contract reversibly to induce switchable attachments and detachments. Our bioinspired device can be integrated onto a robotic arm to attach and release against dry/wet flexible thin objects.

The development of bioinspired switchable adhesive systems has promising solutions in various industrial/medical applications. Switchable and perceptive adhesion regardless of the shape or surface shape of the object is still challenging in dry and aquatic surroundings. We developed an electronic sensory soft adhesive device that recapitulates the attaching, mechanosensory, and decision-making capabilities of a soft adhesion actuator. The soft adhesion actuator of an artificial octopus sucker may precisely control its robust attachment against surfaces with various topologies in wet environments as well as a rapid detachment upon deflation. Carbon nanotube-based strain sensors are three-dimensionally coated onto the irregular surface of the artificial octopus sucker to mimic nerve-like functions of an octopus and identify objects via patterns of strain distribution. An integration with machine learning complements decision-making capabilities to predict the weight and center of gravity for samples with diverse shapes, sizes, and mechanical properties, and this function may be useful in turbid water or fragile environments, where it is difficult to utilize vision.

reversible, and smart adhesives have been implemented in clean transfer systems on large-area glass (or wafers), [5,6] reversible attachments and fixations on various nonflat surfaces (e.g., skin and organs) for medical applications, [5,[7][8][9] and effective locomotion of medical robotics. [10,11] To improve performance and functionality, i.e., the adaptability or directionality of dry adhesion, various nanoscale geometrical and material features have been investigated for amplification of van der Waals forces or mechanical interlocking. Such examples can be found in the hierarchical and slanted microhairs of geckos, [12][13][14] interlocking nanohairs inspired by wing-locking devices of beetles, [15,16] and endoparasite-like microneedles. [17] Recently, additional rules of the 3D architectures of octopi suction cups have been unveiled to explain their enhanced wet adhesion via capillary interaction and suction effects. [5,7] While striking advances have been made in adhesive architectures created on engaged surfaces, another strategy has been investigated to improve adhesion strengths by employing an energy-dissipation layer. [18,19] According to well-established models, [18,20] the energy-dissipation layer plays a key role in improving adhesion strengths during both peel-off and pulloff detachment. In addition, employing heterogenous energydissipation layers inside the adhesives has been highlighted to improve durability and resistance against fatigue, [21] an approach different from previous studies like zip-like microstructured fasteners assisted by mechanical interlocking. [22][23][24] Very recently, versatile tough adhesives have been developed by introducing viscoelastic energy dissipation based on the hysteresis of polymer chains, wherein a tough hydrogel matrix effectively dissipates energy when the interface is stressed during detachment. [18,19] Despite their striking performance on diverse surfaces (e.g., wet and rough), hydrogel-based adhesives with chemical moieties remain challenging to apply in reversible clean-transfer/fixing devices or contamination-free skin patches because of their viscoelastic chemical residues after detachment. [18,19,25] To generate the arresting effect via an energydissipation layer without glue or chemistries, many efforts have focused on subsurface microstructures by controlling various geometries, arrangements (e.g., stripes or plaids), and viscous liquid chambers, resulting in remarkable enhancement In various organisms in nature, the energy-dissipation layers within their adhesive systems are known to play a significant role in enhancement of adhesion performance in pulling and peeling directions. Reported here is that the pedal-muscle structures of snails can be exploited to form a repeatable, microstructure-embedded adhesive, enabling enhanced adhesion in both pulling (13 N cm −2 ) and peeling (20 J m −2 ) directions with excellent repeatability (<1000 cycles). The measured adhesion strengths and energies depend on the geometrical and material parameters of the mi...

Bioinspired soft devices, which possess high adaptability to targeted objects, provide promising solutions for a variety of industrial and medical applications. However, achieving stable and switchable attachment to objects with curved, rough, and irregular surfaces remains difficult, particularly in dry and underwater environments. Here, a highly adaptive soft microstructured switchable adhesion device is presented, which is inspired by the geometric and material characteristics of the tiny denticles on the surface of an octopus sucker. The contact interface of the artificial octopus sucker (AOS) is imprinted with soft, microscale denticles that interact adaptably with highly rough or curved surfaces. Robust and controllable attachment of the AOS with soft microdenticles (AOS-sm) to dry and wet surfaces with diverse morphologies is achieved, allowing conformal attachment on curved and soft objects with high roughness. In addition, AOS-sms assembled with an octopus-arm-inspired soft actuator demonstrate reliable grasping and the transport of complex polyhedrons, rough objects, and soft, delicate, slippery biological samples.

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