Climbing Plant‐Inspired Micropatterned Devices for Reversible Attachment

Abstract

Climbing plants have evolved over millions of years and have adapted to unpredictable scenarios in unique ways. These crucial features make plants an outstanding biological model for scientists and engineers. Inspired by the ratchet‐like attachment mechanism of the hook‐climber Galium aparine, a novel micropatterned flexible mechanical interlocker is fabricated using a 3D direct laser lithography technique. The artificial hooks are designed based on a morphometric analysis of natural hooks. They are characterized in terms of pull‐off and shear forces, both in an array and as individual hooks. The microprinted hooks array shows high values of pull‐off forces (up to F⊥ ≈ 0.4 N cm−2) and shear forces (up to F// ≈ 13.8 N cm−2) on several rough surfaces (i.e., abrasive materials, fabrics, and artificial skin tissues). The contact separation forces of individual artificial hooks are estimated when loads with different orientations are applied (up to F ≈ 0.26 N). In addition, a patterned tape with directional microhooks is integrated into a mobile platform to demonstrate its climbing ability on inclined surfaces of up to 45°. This research opens up new opportunities for prototyping the next generation of mechanical interlockers, particularly for soft‐ and microrobotics, the textile industry, and biomedical fields.

Functional morphology of plants – a key to biomimetic applications

“…New Phytologist 2020). The moving-by-growing abilities of climbing plants have become models for the development of low-mass and low-volume robots capable of anchoring themselves, negotiating voids and more generally climbing (Fiorello et al, 2020;Mazzolai et al, 2020). The vision of combining nature and technology has also been achieved through the development of dynamic nonequilibrium materials systems.…”

“…Cuticles are concept generators for the regulation of water permeability (Mulama et al ., 2019), structural colours (Moyroud et al ., 2017) and sticky or nonfriction surfaces (Bergmann et al ., 2020). The moving‐by‐growing abilities of climbing plants have become models for the development of low‐mass and low‐volume robots capable of anchoring themselves, negotiating voids and more generally climbing (Fiorello et al ., 2020; Mazzolai et al ., 2020). The vision of combining nature and technology has also been achieved through the development of dynamic nonequilibrium materials systems.…”

A Smart Patch with On‐Demand Detachable Adhesion for Bioelectronics

“…Subsequent work found that the reversible adhesion can be realized by imitating ratchet-like attachment mechanism of climbing plants. [18] Recently, smart adhesives inspired by natural animals have been developed, such as the magnetically actuated elastic energy storage adhesives inspired by octopus suckers, [19] the gecko inspired wedged surface utilized for dry adhesion, [20] tree frog inspired hierarchical structure, and insect inspired fibrillar pads for enhanced wet adhesion [21,22] and mussel inspired tissue adhesive hydrogel for sensors. [23] Despite extensive studies on artificial adhesives, they often need to introduce nondegradable cross-linking agent along with complex and time-consuming manufacturing process.…”

Roughness-Induced Adhesive Hysteresis in Self-Affine Fractal Surfaces

“…For example, biomedical devices [6] and structural adhesives [7] must safely adhere to surfaces during their application, but they should be easy to remove for reuse. Moreover, a recent challenge in soft robotics is to create climbing robots with reversible adhesion skills [8].…”