Polymeric Bio‐<scp>I</scp>nspired Dry Adhesives: Van der Waals or Electrostatic Interactions?

Izadi, Hadi; Penlidis, Alexander

doi:10.1002/mren.201300146

Cited by 26 publications

(34 citation statements)

References 103 publications

(612 reference statements)

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“…Interestingly, simultaneous measurement of electric charges and adhesion forces revealed that CE-driven electrostatic interactions have a decisive contribution to the dry adhesion of geckos over these materials. Better insight into the role of CE-driven electrostatic interactions in gecko adhesion is not only very important for understanding the principles of the supreme adhesion of geckos [8,11], but also is fundamentally very crucial in the design and fabrication of synthetic fibrillar dry adhesives [12][13][14], which have been recently hypothesized to be largely affected by CE-generated electrostatic interactions [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Role of contact electrification and electrostatic interactions in gecko adhesion

Izadi

Stewart

Penlidis

2014

J. R. Soc. Interface.

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Geckos, which are capable of walking on walls and hanging from ceilings with the help of micro-/nano-scale hierarchical fibrils (setae) on their toe pads, have become the main prototype in the design and fabrication of fibrillar dry adhesives. As the unique fibrillar feature of the toe pads of geckos allows them to develop an intimate contact with the substrate the animal is walking on or clinging to, it is expected that the toe setae exchange significant numbers of electric charges with the contacted substrate via the contact electrification (CE) phenomenon. Even so, the possibility of the occurrence of CE and the contribution of the resulting electrostatic interactions to the dry adhesion of geckos have been overlooked for several decades. In this study, by measuring the magnitude of the electric charges, together with the adhesion forces, that gecko foot pads develop in contact with different materials, we have clarified for the first time that CE does contribute effectively to gecko adhesion. More importantly, we have demonstrated that it is the CE-driven electrostatic interactions which dictate the strength of gecko adhesion, and not the van der Waals or capillary forces which are conventionally considered as the main source of gecko adhesion.

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Section: Introductionmentioning

confidence: 99%

Role of contact electrification and electrostatic interactions in gecko adhesion

Izadi

Stewart

Penlidis

2014

J. R. Soc. Interface.

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“…Electrostatic forces (Figure a) are similar to the van der Waals forces in essence . They are the attractive or repulsive forces between two surfaces with opposite or same charges .…”

Section: Theoretical Background and Progress Of The Peeling Modelmentioning

confidence: 96%

Understanding Surface Adhesion in Nature: A Peeling Model

Zhang

et al. 2016

Advanced Science

109

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Nature often exhibits various interesting and unique adhesive surfaces. The attempt to understand the natural adhesion phenomena can continuously guide the design of artificial adhesive surfaces by proposing simplified models of surface adhesion. Among those models, a peeling model can often effectively reflect the adhesive property between two surfaces during their attachment and detachment processes. In the context, this review summarizes the recent advances about the peeling model in understanding unique adhesive properties on natural and artificial surfaces. It mainly includes four parts: a brief introduction to natural surface adhesion, the theoretical basis and progress of the peeling model, application of the peeling model, and finally, conclusions. It is believed that this review is helpful to various fields, such as surface engineering, biomedicine, microelectronics, and so on.

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“…However, the adhesion mechanism of animals' hairy attachment organs continues to constitute a controversial matter. Although extant studies over several years confirmed that van der Waals interaction [6,7] and capillary forces [8,9] play dominant roles in setae adhesion, electrostatic attraction is increasingly invoked [10,11] to interpret the adhesion of hairy systems [9,10]. It is easy to positively tribo-electrify hair [12,13], and thus animals' hairy attachment organs are expected to become charged and subsequently generate electrostatic forces [10,14] as long as they interact with the environment to obtain forces to drive their locomotion.…”

Section: Introductionmentioning

confidence: 99%

Synchronous measurement of tribocharge and force at the footpads of freely moving animals

et al. 2017

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Hypothesis on electrostatic attraction mechanisms involving the hairy adhesion of climbing animals has been a matter of controversy for several years. The detection of tribocharge and forces at attachment organs of animals is a practical method of clarifying the dispute with respect to electrostatic attraction in the attachment of animals. Nonetheless, the tribo-electrification is rarely examined in the contact-adhesion of animals (especially in their free and autonomous attachment) due to the lack of available devices. Therefore, the present study involves establishing a method and an apparatus that enables synchronous detection of tribocharge and contact forces to study tribo-electrification in the free locomotion of geckos. A type of a combined sensor unit that consists of a three-dimensional force transducer and a capacitor-based charge probe is used to measure contact forces and tribocharge with a magnitude corresponding to several nano-Coulombs at a footpad of geckos when they climb vertically upward on an acrylic oligomer substrate. The experimental results indicate that tribocharge at the footpads of geckos is related to contact forces and contact areas. The measured charge allows the expectation of an exact attraction with magnitude corresponding to dozens of newtons per square meter and provides a probability of examining tribo-electrification in animal attachment from a macro level.

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Polymeric Bio‐Inspired Dry Adhesives: Van der Waals or Electrostatic Interactions?

Cited by 26 publications

References 103 publications

Role of contact electrification and electrostatic interactions in gecko adhesion

Role of contact electrification and electrostatic interactions in gecko adhesion

Understanding Surface Adhesion in Nature: A Peeling Model

Synchronous measurement of tribocharge and force at the footpads of freely moving animals

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