En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays

• Slawomir Boncel,
• Sebastian W. Pattinson,
• Valérie Geiser,
• Milo S. P. Shaffer and
• Krzysztof K. K. Koziol

Beilstein J. Nanotechnol. 2014, 5, 219–233, doi:10.3762/bjnano.5.24

• composites of enhanced thermal and electrical conductivity [18][19], superhydrophobic surfaces [20], separation membranes [21] and sensors [22]. As for aligned N-CNT arrays, to mention the most recent and prominent applications, they have shown to be suitable catalysts for the reduction of oxygen in alkaline

Synthesis of boron nitride nanotubes from unprocessed colemanite

• Saban Kalay,
• Zehra Yilmaz and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2013, 4, 843–851, doi:10.3762/bjnano.4.95

• that of CNTs [6]. It has been theoretically demonstrated that BNNTs can capture ions selectively creating superhydrophobic surfaces [7][8]. Since hexagonal boron nitrides (h-BNs) have a sp2 hybridization, the BNNTs can interact with polymers possessing aromatic rings via π-π interaction. Therefore, the

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

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

• size of the surface features reaches 1 μm. Keywords: contact angle; hysteresis; superhydrophobic; wetting; Introduction Superhydrophobic surfaces have recently been the focus of considerable scientific interest [1][2][3][4][5][6][7][8][9][10]. This is due to the fact that artificial superhydrophobic

• measurements (around 2 μL) were not very mobile, requiring considerable tilting angles (>30°) to roll off. Especially when compared to other materials where even smallest drops roll off at tilting angles of only 5° or less (see, for example, the superhydrophobic surfaces from [2][3][4][5][6][7][8][9]), this

• surfaces are promising candidates for a number of practical applications, for example, self-cleaning windows, clothing, and also microfludic systems. Drops that come into contact with a superhydrophobic material retain a nearly spherical shape and can easily roll off. As has been shown, this effect results

Hierarchically structured superhydrophobic flowers with low hysteresis of the wild pansy (Viola tricolor) – new design principles for biomimetic materials

• Anna J. Schulte,
• Damian M. Droste,
• Kerstin Koch and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2011, 2, 228–236, doi:10.3762/bjnano.2.27

• Jiang [16] proposed five different states for superhydrophobic surfaces, where the lotus and gecko states are treated as special cases in the Cassie–Baxter model. Feng et al. [17] proposed a sixth superhydrophobic state, called the “Cassie impregnating wetting state” or “petal effect”. Both describe

• superhydrophobic surfaces with high adhesive forces to water, and this means that the wetted surface area is smaller than in the Wenzel model but larger than in the Cassie–Baxter model. Feng et al. [17] demonstrated this effect on rose flowers (petals). The surfaces of petals are often morphologically

• attempts have been made to fabricate superhydrophobic surfaces with high adhesion properties inspired by rose petals [20][22][23][24][25]. Bhushan and Her [25], for example, replicated dried and thereby collapsed, micropapillae, and examined the wetting behavior of these structurally changed petals

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

• become an icon for superhydrophobicity and self-cleaning surfaces, and have led to the concept of the ‘Lotus effect’. Although many other plants have superhydrophobic surfaces with almost similar contact angles, the lotus shows better stability and perfection of its water repellency. Here, we compare the

• cause pinning of the drops. In contrast, advancing contact angles depend weakly on such irregularities. Thus, the adhesion data correlate better with receding contact angles and hysteresis and indicate the perfection and defects of superhydrophobic surfaces. Mechanical protection of the wax crystals by

• ]. Superhydrophobic surfaces which feature permanent air retention under water are found on animals (some birds, spiders and insects). An outstanding air-retention capability is found, for example, for the aquatic insect Notonecta glauca (‘backswimmer’) [26][27]. Here the water repellency is created by a two-level

Capillary origami: superhydrophobic ribbon surfaces and liquid marbles

• Glen McHale,
• Michael I. Newton,
• Neil J. Shirtcliffe and
• Nicasio R. Geraldi

Beilstein J. Nanotechnol. 2011, 2, 145–151, doi:10.3762/bjnano.2.18

• wrapping and relate it to the same transition condition known to apply to superhydrophobic surfaces. The results are given for both droplets being wrapped by thin ribbons and for solid grains encapsulating droplets to form liquid marbles. Keywords: capillary origami; Cassie; contact angle

• roughness factor rW and using the definition of the equilibrium contact angle on a rigid substrate of cosθe = (γSV − γSL)/γLV gives, Defining the Cassie–Baxter combination cosθCB = φscosθe − (1−φs), which is familiar from the modelling of droplets on superhydrophobic surfaces, gives, The similarity of

• therefore seems likely that to fully understand superhydrophobic surfaces, the flexible nature of elements of surfaces needs to be understood. Using a model of a thin ribbon (strip) substrate we have shown that relaxing the assumption of a rigid substrate allows a contacting droplet to shape and bend the

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

• Biomechanics, Christian-Albrechts-University of Kiel, Am Botanischen Garten 1–9, Kiel, 24098, Germany Lehrstuhl Strömungsmechanik, Universität Rostock, Albert Einstein Str. 2, Rostock, 18051, Germany 10.3762/bjnano.2.17 Abstract Superhydrophobic surfaces of plants and animals are of great interest for

• biomimetic applications. Whereas the self-cleaning properties of superhydrophobic surfaces have been extensively investigated, their ability to retain an air film while submerged under water has not, in the past, received much attention. Nevertheless, air retaining surfaces are of great economic and

• the air film on most superhydrophobic surfaces usually lasts no longer than a few days, a few semi-aquatic plants and insects are able to hold an air film over a longer time period. Currently, we found high air film persistence under hydrostatic conditions for the elytra of the backswimmer Notonecta

Biomimetic materials

• Wilhelm Barthlott and
• Kerstin Koch

Beilstein J. Nanotechnol. 2011, 2, 135–136, doi:10.3762/bjnano.2.16

• ) and radiation (e.g., sunlight). Boundary layers and, in particular, superhydrophobic surfaces and their interactions with the environment were thus the focus of this Thematic Series on Biomimetic materials. The most interesting phenomena happen on boundary layers: from the biosphere at the boundary

Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

• Bharat Bhushan

Beilstein J. Nanotechnol. 2011, 2, 66–84, doi:10.3762/bjnano.2.9

• hydrophobicity using a dynamic AFM method [16][33]. Data on one hydrophilic, one hydrophobic, and one superhydrophobic surface are presented in Table 2. Mica was taken as the hydrophilic surface. Hydrophobic and superhydrophobic surfaces were fabricated by deposition of evaporated plant wax on smooth epoxy