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Abstract The ability to control adhesion on demand is important for a broad range of applications, including the gripping and manipulation of objects in robotics and manufacturing, and the temporary attachment of wearable devices. Despite recent advances in tunable adhesive materials, most existing solutions have modest adhesion strength and are limited by a compromise between the maximum and minimum adhesion, where increased strength prevents the release of lighter objects. To overcome these challenges, thermally responsive polymers, which can exhibit both high stiffness and a large reduction in stiffness via heating, have the potential to enable strong and tunable adhesion. Here, a microstructured composite adhesive with high strength (>2 MPa) and dynamically tunable adhesion (16×) is realized using a solvent‐assisted molding technique. The adhesive consists of an array of composite micropillars whose small scale and material composition enable strong and tunable adhesion. While thermally actuated systems often have slow response times, it is shown that miniaturization allows response times to be reduced to <1s for heating and <10s for cooling. These strong, fast, and dynamically tunable adhesives offer advantages over existing solutions and can be manufactured for practical adoption through the scalable solvent‐assisted molding technique.
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Dynamically Tunable Dry Adhesion via Subsurface Stiffness Modulation
Abstract Tunable dry adhesion has a range of applications, including transfer printing, climbing robots, and gripping in automated manufacturing processes. Here, a novel concept to achieve dynamically tunable dry adhesion via modulation of the stiffness of subsurface mechanical elements is introduced and demonstrated. A composite post structure, consisting of an elastomer shell and a core with a stiffness that can be tuned via application of electrical voltage, is fabricated. In the nonactivated state, the core is stiff and the effective adhesion strength between the composite post and contact surface is high. Activation of the core via application of electrical voltage reduces the stiffness of the core, resulting in a change in the stress distribution and driving force for delamination at the interface and, thus a reduction in the effective adhesion strength. The adhesion of composite posts with a range of dimensions is characterized and activation of the core is shown to reduce the adhesion by as much as a factor of 6. The experimentally observed reduction in adhesion is primarily due to the change in stiffness of the core. However, the activation of the core also results in heating of the interface and this plays a secondary role in the adhesion change.
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- PAR ID:
- 10062887
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 5
- Issue:
- 18
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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