Robust and strong adhesion is highly required for reversible adhesions. Inspired by gecko setae and octopus sucker, micropillar array with frustum of conical micropits (FCM) was fabricated by direct laser writing lithography. With an optimized micropit in FCM, the adhesion strength of 1.2 MPa is achieved under a loading force of 5 mN, which is 3.7 and 2.1 times the micropillars with flat punch top and circular conical micropit, respectively. Under a loading force larger than 3 mN, compliant contacts are formed between FCM micropillars and the counterpart surface, which results in a uniformly distributed stress at the separating interface, an instantaneous detachment of multiple FCM micropillars, and therefore a strong adhesion. Moreover, the adhesion of FCM is quite robust that 1000 cycles of attaching and detaching have no influence on the adhesion performance. The work here not only provides a bioinspired structure for strong and robust adhesion but also consolidates the concept of combining features from different biological systems to create new functional materials.
Xiaoliang Zou,Xuechuan Wang,Mengmeng Gou,Ouyang Yue,Zhongxue Bai,Huijie Zhang,Xinhua Liu
Bio-based adhesive electroactive hydrogels as electronics are of significant research interest in health monitoring systems, wearable devices and smart home systems. Herein, a series of ultra-strong adhesive, self-healable and electroactive nanocomposite hydrogels (CAM-Gels) driven by integrated molecular-chain entanglements, hydrogen bonds, chelation and electrostatic interactions was nano-engineered by compounding biomass gelatin (Gel) and chitosan (CS), acrylamide (AM), multi-walled carbon nanotubes (MWCNTs) and FeCl3 though a simple one-pot method as a conductive adhesive layer for the bio-fabrication of a brand new sandwich-inspired leather-based smart electronic sensing floor (e-floor). Comprehensive experiments showed that the integration of abundant active groups and cohesion among the constituents endowed CAM-Gels with desired adhesive ability towards various substrates. Exhilaratingly, CAM-Gels exhibited ultra-strong adhesive strength on natural hydrogenoid skin, superior to that of currently reported polyurethane adhesives, bio-based adhesives and mussel-inspired adhesives. Owing to the dynamic reversible physical crosslinking, CAM-Gels showed on-demand self-healing ability. Moreover, CAM-Gels presented the accurate real-time monitoring of comprehensive large- and small-scale human activities, demonstrating its significant potential for sensor electronics. Furthermore, the proposed leather-based e-floor exhibited a repeatable and regular electrical signal as expected, substantiating that the e-floor can be used for accurately tracking people's daily activities. The e-floor breaks new ground for leather-based electronics, which will have potential applications in smart homes.
危险品化学品经营许可证（带存储）