Measuring air layer volumes retained by submerged floating-ferns Salvinia and biomimetic superhydrophobic surfaces

• Matthias J. Mayser,
• Holger F. Bohn,
• Meike Reker and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2014, 5, 812–821, doi:10.3762/bjnano.5.93

• upper leaf side of floating ferns of the genus Salvinia air layers are reported to persist from several days up to months [30][31][32]. Responsible for the long-term air retention in these organisms is a dense cover of elaborate, hydrophobic hairs on their surfaces (Figure 1). In Salvinia these hairs

• possess a multiscale roughness on several hierarchical levels resulting in a stable Cassie wetting state [17]. In the floating fern genus Salvinia four different shapes of such hairs (trichomes) have been described [33]. In the simplest case these are individual multicellular, uniseriate trichomes. In the

• most complex case four multicellular, uniseriate trichomes are grouped on top of an emergence and join at their tips forming a so called “egg beater” hair. These hairs with heights between approximately 300 and 2200 µm cover the major part of the upper leaf side (Figure 1). Towards the margin of the

Hairy suckers: the surface microstructure and its possible functional significance in the Octopus vulgaris sucker

• Francesca Tramacere,
• Esther Appel,
• Barbara Mazzolai and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2014, 5, 561–565, doi:10.3762/bjnano.5.66

• completely covered by a dense network of hair-like micro-outgrowths. This finding is particularly important because it provides another demonstration of the role of hair-structures in a sealing mechanism in water, similar to that previously described for clingfish and abalones. Moreover, the discovered hairs

• dense network of brush-like hairs, which are approximately 50 µm (±18 µm, n = 25) long and have a diameter of 2 µm (±0.9 µm, n = 25) (Figure 1e,f). Each hair apically branches into very small filaments, which are approximately 5 µm (±2.8 µm, n = 18) long and have a diameter of 0.3 µm (±0.2 µm, n = 25

• this work is the presence of hairs on the acetabular protuberance. This is of particular interest because to the best of our knowledge, these microstructures are unknown in the literature. Moreover, the presence of such hierarchical hairs on the entire surface of the acetabular protuberance supports

Magnesiothermic conversion of the silica-mineralizing golden algae Mallomonas caudata and Synura petersenii to elemental silicon with high geometric precision

• Janina Petrack,
• Steffen Jost,
• Jens Boenigk and
• Matthias Epple

Beilstein J. Nanotechnol. 2014, 5, 554–560, doi:10.3762/bjnano.5.65

• ]. Chrysophytes, and stramenopiles in general are heterokont, i.e., they have a long flagellum bearing tripartite hairs and a short flagellum without such hairs. The flagella are used for locomotion [19]. The chrysophytes are usually photoautotrophic even though some lineages of the Chrysophyceae have secondarily

Grain boundaries and coincidence site lattices in the corneal nanonipple structure of the Mourning Cloak butterfly

• Ken C. Lee and
• Uwe Erb

Beilstein J. Nanotechnol. 2013, 4, 292–299, doi:10.3762/bjnano.4.32

• of the Mourning Cloak butterfly is covered with randomly distributed tiny hairs (about 4 µm in diameter), which usually grow at the triple junctions between the ommatidia. In Figure 1, the bases of fractured hairs are visible on three of the triple junctions. Figure 1 also shows areas with

Micro to nano: Surface size scale and superhydrophobicity

• Christian Dorrer and
• Jürgen Rühe

Beilstein J. Nanotechnol. 2011, 2, 327–332, doi:10.3762/bjnano.2.38

• was observed that the lotus leaf looses its water-repellent properties if the source of the nanoscale roughness, which originates from fine hairs with a diameter of a few nanometers, is removed [19]. In addition, hydrophobicized, microscale surfaces with posts 4 μm wide become “truly” superhydrophobic

Determination of object position, vortex shedding frequency and flow velocity using artificial lateral line canals

• Adrian Klein and
• Horst Bleckmann

Beilstein J. Nanotechnol. 2011, 2, 276–283, doi:10.3762/bjnano.2.32

• cylinder. Keywords: artificial lateral line; biomimetics; flow sensor; mechanoreception; optical sensor; Introduction Nature has invented a stunning diversity of sensory systems whose small size and high sensitivity is so far unmatched by man-made devices. Flow sensors based on hairs are located on the

• (including distance) of the object and the direction of object motion [15]. The sensory hairs of crustaceans, insects and spiders and the lateral line system of fish have inspired engineers to develop artificial air [16] and water flow sensors [17][18][19] based on microelectromechanical system (MEMS

• sensory hairs of insects and spiders [16][23] and to the superficial neuromast system of fish. However, an engineering equivalent of the fish lateral line canal system did not previously exist, and therefore we have built artificial lateral line canals (ALLCs) and equipped them with artificial neuromasts

Sorting of droplets by migration on structured surfaces

• Wilfried Konrad and
• Anita Roth-Nebelsick

Beilstein J. Nanotechnol. 2011, 2, 215–221, doi:10.3762/bjnano.2.25

• ]. Plant surfaces are also known to develop a huge variety of patterns on different length scales [11]. A prominent example are the leaf wax structures leading to superhydrophobicity and the Lotus-effect [12]. Larger structures are also common, e.g., trichomes (leaf hairs) or wart-like structures. Stomata

Moisture harvesting and water transport through specialized micro-structures on the integument of lizards

• Philipp Comanns,
• Christian Effertz,
• Florian Hischen,
• Konrad Staudt,
• Wolfgang Böhme and
• Werner Baumgartner

Beilstein J. Nanotechnol. 2011, 2, 204–214, doi:10.3762/bjnano.2.24

• . The integument consists of the skin and its derivatives such as scales, feathers, hairs and nails and has a variety of functions: Next to mechanical protection and prevention of water loss from lower tissue layers, it serves also for temperature regulation and as a transmitter for tactile stimuli. The

Superhydrophobicity in perfection: the outstanding properties of the lotus leaf

• Hans J. Ensikat,
• Petra Ditsche-Kuru,
• Christoph Neinhuis and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2011, 2, 152–161, doi:10.3762/bjnano.2.19

• been known for a long time that plant surfaces covered with epicuticular wax crystals are water repellent, and that this feature is enhanced when the epidermis has additional structures such as papillae or hairs [5][6]. Neinhuis and Barthlott (1997) [7] presented an overview of more than 200 species

• material, which is too fragile for most technical applications. A different architecture is found on some species with hairy leaf surfaces. The water fern (some species of the genus Salvinia) and Pistia stratioides leaves retain a relatively thick air layer between hydrophobic hairs when submersed in water

• structure consisting of coarse hairs which can hold a relatively thick air layer, and extremely fine hairs which ensure a high capillary pressure. The biopolymers used in these structures have the advantage of a much higher strength than waxes. On the other hand, the plant surfaces have the capability to

Superhydrophobic surfaces of the water bug Notonecta glauca: a model for friction reduction and air retention

• Petra Ditsche-Kuru,
• Erik S. Schneider,
• Jan-Erik Melskotte,
• Martin Brede,
• Alfred Leder and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2011, 2, 137–144, doi:10.3762/bjnano.2.17

• originating from an adjacent cell and are classified as true hairs, while microtrichia originating from one cell and are, by definition, not really hairs [27][28]. Three different body parts of Notonecta glauca with different surface structures were selected for further investigations; a pure setae structure