High strength reversible adhesive closures

Abstract

Closures such as buttons, clasps, zippers, and hook‐and‐loops find widespread use in daily life, and all work by mechanical interlocking. However, these traditional closures are often rigid, lose performance with age, and can produce a harsh sound during use. Here high strength (>50 N cm−2), reusable, and nearly silent closure devices are fabricated based on recently developed fibril‐less gecko‐inspired adhesives. Guided by a reversible adhesion scaling law, the closure force capacity is tuned by modifying the closure materials and geometry. A simple analytical model is presented which accurately predicts system performance, based on the reversible adhesion scaling parameter. The force capacity of these adhesive closures is measured and compared to commercially‐available hook‐and‐loop closures, and it is found that the adhesive closures sustain forces that are 4.4 times greater for comparable geometry. The sound of release is also quantified and shown to be minimal for adhesive closures. This work provides motivation to develop new high strength, reusable closures for commercial and industrial applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1783–1790

Reversible Bonding of Aromatic Thermosetting Copolyesters for In‐Space Assembly

“…Additionally, the reversibility scheme developed in this work has been shown to be operable for more than 50 cycles without observed performance degradation. In comparison to reversible adhesive systems that exist in the literature, the 28.7 MPa bonding strength at the 51st cycle showed significantly higher strength value than the best found in the literature—10 MPa, while demonstrating reversibility for cycles comparable to the best seen in literature …”

“…One category is to use a micro‐patterned surface that mimics the bio‐structures and the other category is to solely apply non‐patterned adhesive polymers. The adhesion force between different surfaces is generated due to van der Waals forces, capillary forces, mechanical interlocking, covalent bond, and hydrogen bonding . The patterned surfaces can have higher compliance and conformability to various substrate topographies, thus may exhibit better adhesion, compared to non‐patterned counterparts …”

Low‐Voltage Reversible Electroadhesion of Ionoelastomer Junctions

“…We note that in the current implementation, ionoelastomer electro-adhesives provide enhanced adhesion only between two specific materials of opposite polarity. While such selective complementary adhesion can be useful in its own right (e.g., Velcro, zippers and buttons), [44] it would also be valuable to achieve low-voltage adhesion to a greater variety of other surfaces using ionoelastomers. To this end, we are currently pursuing approaches to laterally pattern high surface area electrodes and alternating domains of ionoelastomers of opposite polarity as an analog to the interdigitated structures commonly employed to enable versatile adhesion of dielectric electro-adhesives to different types of materials.…”

Functional Polymeric Materials Inspired by Geckos, Mussels, and Spider Silk

“…In the last years, an opposite trend emerged: the development of dry adhesives that are still based on several design principles of a gecko foot, but without complex surface geometries. The most prominent contributions of this approach are made by Crosby and co‐workers that developed nonfibrillar adhesives with a load‐bearing structure that is compliant in the normal direction to the surface, yet comparatively stiff in the loading direction . Alternatively, wrinkling techniques were used to create relatively simple structured surfaces, retaining the design feature to control adhesion by structuring the surface …”

“…The most prominent contributions of this approach are made by Crosby and co-workers that developed nonfibrillar adhesives with a load-bearing structure that is compliant in the normal direction to the surface, yet comparatively stiff in the loading direction. [36][37][38][39] Alternatively, wrinkling techniques were used to create relatively simple structured surfaces, retaining the design feature to control adhesion by structuring the surface. [40][41][42][43]…”