Enhancement of Capillary Forces by Multiple Liquid Bridges

Souza, Emerson J. de; Brinkmann, Martin; Mohrdieck, Camilla; Arzt, Eduard

doi:10.1021/la8005376

Cited by 83 publications

(103 citation statements)

References 45 publications

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“…This theory states that adhesive force is proportional to the length of the contact; therefore, by splitting up the contact zone into many small areas of contact, the total adhesive force can be increased in direct proportion to the density of these small areas (Arzt et al, 2003). This principle clearly applies to wet adhesion (De Souza et al, 2008). However, as the major force component of wet adhesion is capillarity, it is necessary that an air-water interface (meniscus) should surround each small area of contact.…”

Section: Roles For Toe Pad Microstructuresmentioning

confidence: 94%

Ultrastructure and physical properties of an adhesive surface, the toe pad epithelium of the tree frog, Litoria caerulea White

Scholz

Barnes

Smith

et al. 2009

Journal of Experimental Biology

104

118

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SUMMARYKnowledge of both surface structure and physical properties such as stiffness and elasticity are essential to understanding any adhesive system. In this study of an adhesion surface in the tree frog, Litoria caerulea White, a variety of techniques including atomic force microscopy were used to investigate the microstructure and properties of an epithelium that adheres through wet adhesion. Litoria toe pads consist of a hexagonal array of flat-topped epithelial cells, separated by mucus-filled channels. Under an atomic force microscope, this ʻflatʼ surface is highly structured at the nanoscale, consisting of a tightly packed array of columnar nanopillars (described as hemidesmosomes by previous authors), 326±84 nm in diameter, each of which possesses a central dimple 8±4 nm in depth. In fixed tissue (transmission electron microscopy), the nanopillars are approximately as tall as they are broad. At the gross anatomical level, larger toe pads may be subdivided into medial and lateral parts by two large grooves. Although the whole toe pad is soft and easily deformable, the epithelium itself has an effective elastic modulus equivalent to silicon rubber (mean E eff =14.4±20.9 MPa; median E eff =5.7 MPa), as measured by the atomic force microscope in nanoindentation mode. The functions of these structures are discussed in terms of maximising adhesive and frictional forces by conforming closely to surface irregularities at different length scales and maintaining an extremely thin fluid layer between pad and substrate. The biomimetic implications of these findings are reviewed.

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Section: Roles For Toe Pad Microstructuresmentioning

confidence: 94%

Ultrastructure and physical properties of an adhesive surface, the toe pad epithelium of the tree frog, Litoria caerulea White

Scholz

Barnes

Smith

et al. 2009

Journal of Experimental Biology

104

118

View full text Add to dashboard Cite

show abstract

“…The dependence of capillary forces on the contact angle of the surface has also been the subject of models (De Souza et al, 2008a). The authors analysed the separation force between two homogeneous surfaces with a constant liquid volume between them and used the number of liquid bridges and the contact angle as variable factors.…”

Section: Friction Forcementioning

confidence: 99%

“…The capillary forces, in turn, strongly depend on the contact angle between the fluid and the surface of particular substrate (e.g. De Souza et al, 2008a).…”

Section: Introductionmentioning

confidence: 99%

Attachment ofGalerucella nymphaeae(Coleoptera, Chrysomelidae)to surfaces with different surface energy

Grohmann

Blankenstein

Koops

et al. 2014

Journal of Experimental Biology

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Numerous studies deal with insect attachment onto surfaces with different roughness; however, little is known about insect attachment onto surfaces that have different chemistry. In the present study, we describe the attachment structures of the water-lily leaf beetle Galerucella nymphaeae and test the hypothesis that the larval and adult stages generate the strongest attachment on surfaces with contact angles that are similar to those of leaves of their host plants. The larvae bear a smooth attachment system with arolium-like structures at their legs and a pygopodium at the abdomen tip. Adults have pointed setae on the ventral side of the two proximal tarsomeres and densely arranged spatula-shaped ones on their third tarsomere. In a centrifugal force tester, larvae and adults attained the highest friction forces and safety factors on surfaces with a water contact angle of 83 deg compared to those of 6, 26 and 109 deg. This comes close to the contact angle of their host plant Nuphar lutea (86 deg). The similarity in larval and adult performances might be a result of the similar chemical composition of their attachment fluid. We compare our findings with previous studies on the forces that insects generate on surfaces with different surface energies.

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“…The capillary bridge between two structured surfaces can be used as a simplified model for biological adhesives, microfluidic channels, and self-assembly (Gau et al, 1999;Bush et al, 2010;De Souza et al, 2008;Broesch et al, 2014;Mermoz et al, 2012;Ferraro et al, 2012;Luo et al, 2014). In particular, a structured surface has the shape characteristics of a slender rectangle, which has great potential for application to the field of microchannels (Gau et al, 1999;Valencia et al, 2001;Lipowsky et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Shape and force analysis of capillary bridge between two slender structured surfaces

Zhu

Jia

et al. 2015

Mech. Sci.

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Abstract. When a capillary bridge of a constant volume is formed between two surfaces, the shape of the liquid bridge will change as the separation between those surfaces is varied. To investigate the variable forces and Laplace pressure of the capillary bridge, as the shape the bridge evolves, a pseudo-three-dimensional force model of the capillary bridge is developed. Based on the characteristics of the slender structured surface, an efficient method is employed to directly solve the differential equations defining the shape of the capillary bridge. The spacing between the plates satisfying the liquid confined within the hydrophobic region of the structured surface is calculated. The method described in this paper can prevent meshing liquid surfaces such that, compared with Surface Evolver simulations, the computing speed is greatly improved. Finally, by comparing the results of the finite element simulations performed with Surface Evolver with those of the method employed in this paper, the practicality of the method is demonstrated.

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Enhancement of Capillary Forces by Multiple Liquid Bridges

Cited by 83 publications

References 45 publications

Ultrastructure and physical properties of an adhesive surface, the toe pad epithelium of the tree frog, Litoria caerulea White

Ultrastructure and physical properties of an adhesive surface, the toe pad epithelium of the tree frog, Litoria caerulea White

Attachment ofGalerucella nymphaeae(Coleoptera, Chrysomelidae)to surfaces with different surface energy

Shape and force analysis of capillary bridge between two slender structured surfaces

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