Bioinspired Superdurable Pestle‐Loop Mechanical Interlocker with Tunable Peeling Force, Strong Shear Adhesion, and Low Noise

Abstract

Velcro, the most typical hook‐loop interlocker, often suffers from undesirable deformation, breaking, and noise because of the structure of the hook. Inspired by the arrester system of dragonfly, a new mechanical interlocker with a nylon pestle instead of the traditional hook is developed. The pestle‐loop mechanical interlocker shows a tunable peeling force from 0.4 ± 0.14 to 6.5 ± 0.72 N and the shear adhesion force of pestle‐loop mechanical interlocker is about twice as much as that of velcro. The pestle tape can be separated and fastened with the loop tape up to 30 000 cycles while keeping the original adhesive force and the pestle structure. In comparison, only after 4000 cycles most hooks of the commercial velcro are deformed and even broken, completely losing their adhesive function and their hook structure. These experimental results are further supported by finite element simulitions—the base of pestle mainly bears the separation‐caused strain while the middle of hook does. Notably, the sound volume during the separation of pestle‐loop mechanical interlocker is merely 49 ± 7.4 dB, much lower than 70 ± 3.5 dB produced by the velcro.

Climbing Plant‐Inspired Micropatterned Devices for Reversible Attachment

“…The performance of the hooks during interlocking strongly depends on three main factors: i) the size and shape of the hook, ii) the texture of the contact substrate, and iii) the preload applied. [ 6,26,31 ]…”

“…[ 2 ] Biologically inspired approaches are now being used to fabricate new smart solutions for gripping and anchoring. These solutions mimic the morphological features of the selected animals (e.g., the remora disc, [ 3 ] octopus sucker, [ 4 ] gecko foot, [ 5 ] insect pads), [ 6 ] and plants (e.g., trichomes). [ 7,8 ] A growing interest concerns the use of bioinspired architectures to develop novel materials for reversible attachment and detachment on different rough surfaces, using different strategies, such as mechanical interlocking, [ 9–11 ] van der Waals forces, [ 12–14 ] or suction cups [ 15 ] (see Table S1, Supporting Information, for a brief overview of the bioinspired structures for rough surfaces).…”

“…[ 16 ] To date, the most famous hook‐based mechanical interlocker is Velcro, which was inspired by burdock seeds. In addition, other anchoring systems for mechanical interlocking have been developed and have shown great potential, including probabilistic and fabric fasteners, [ 6,16,17 ] dry adhesives, [ 7 ] medical patches for skin interlocking, [ 10 ] and microspines for climbing robots [ 18–20 ] or grippers. [ 21,22 ]…”

Bioinspired Mechanically Interlocking Structures

“…Similar penetrating interlocks were designed to Tree root-inspired stretchable electrode [4] Au thin-film, PDMS PDMS % 1-3 MPa Thickness ≥ 300 nm; Nanopile length ≥ 0.5 μm 2.6 MPa n/a Au % 59-62 GPa [40] Deformable MN tissue Adhesive [2a] PS homopolymer (inner Buckling-based strong dry adhesive [24] SMP 3. Dragonfly-inspired pestle-loop [26] Nylon Figure 2. Pathways from understanding the interlocking structures of each critical bioinspiration, to the gain of functionalities toward practical applications (static interlocks).…”

Biomimetic Surface with Tunable Frictional Anisotropy Enabled by Photothermogenesis‐Induced Supporting Layer Rigidity Variation

“…The present photocontrolled frictional anisotropy biomimetic surfaces will be promising for remote control devices used in various fields. For proof‐of‐concept purpose, a natural hook‐and‐loop fastener like the Velcro type strip was conducted with the resultant surface for remote control release. As shown in Figure a and Movie S1 (Supporting Information), the biomimetic surface was fixed on the inclined board (≈30°) and hanged on 50 g weight by two hook‐like spines (the inset of Figure a).…”