Biomimetics on the micro- and nanoscale – The 25th anniversary of the lotus effect

• Matthias Mail,
• Kerstin Koch,
• Thomas Speck,
• William M. Megill and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2023, 14, 850–856, doi:10.3762/bjnano.14.69

• Zoology, Christian-Albrechts-University of Kiel, Am Botanischen Garten 1–9, D-24118 Kiel, Germany 10.3762/bjnano.14.69 Keywords: biomimetic surfaces; hydrophobicity; lotus effect; Salvinia effect; superhydrophobicity; wettability; In 1997, Wilhelm Barthlott and Christoph Neinhuis published the paper

• of superhydrophobic pads covered with nanofur for the efficient clean-up of oil spills”. Nanofurs are densely packed hairy surfaces which demonstrate superhydrophobicity, functioning similarly to the lotus leaf whose science we are celebrating with this thematic issue. As with many biomimetic

• colour is produced by the hierarchical micro- and nanostructure of the surface. The reflection of light depends on the angle of incidence. In addition to superhydrophobicity, these results suggest that the scales have another function – their hierarchical structures produce the brilliant white colour

The origin of black and white coloration of the Asian tiger mosquito Aedes albopictus (Diptera: Culicidae)

• Manuela Rebora,
• Gianandrea Salerno,
• Silvana Piersanti,
• Alexander Kovalev and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2023, 14, 496–508, doi:10.3762/bjnano.14.41

• related to the superhydrophobicity of their body surface, as an adaptation of an aquatic insect to the subaerial life at the adult stage. Indeed, leg scales with their nanostructures are able to entrap air [11][12][13] and play an important role in contact with water during egg laying, giving the mosquito

Dry under water: air retaining properties of large-scale elastomer foils covered with mushroom-shaped surface microstructures

• Matthias Mail,
• Stefan Walheim,
• Thomas Schimmel,
• Wilhelm Barthlott,
• Stanislav N. Gorb and
• Lars Heepe

Beilstein J. Nanotechnol. 2022, 13, 1370–1379, doi:10.3762/bjnano.13.113

• air lubrication; Salvinia effect; superhydrophobicity; Introduction Superhydrophobicity is one of the key innovations in the biological evolution of organisms for the conquest of land [1]. Recently it was shown that this fascinating surface property evolved already in the cyanobacterium Hassallia [2

Roll-to-roll fabrication of superhydrophobic pads covered with nanofur for the efficient clean-up of oil spills

• Patrick Weiser,
• Robin Kietz,
• Marc Schneider,
• Matthias Worgull and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2022, 13, 1228–1239, doi:10.3762/bjnano.13.102

• . These are well-suited for the cleanup of small oil spills. Keywords: hot embossing; lotus effect; nanofur; nanopads; oil spill cleanup; oil water separation; roll-to-roll; R2R; superhydrophobicity; Introduction Self-cleaning surfaces utilizing the famous lotus effect have gained significant importance

• of PP nanofur produced in the fashion described above (see Figure 5). The contact angle is about 154° at first but dropped by 4° after the first turns of the rollers before it became nearly constant with values slightly below 150°. While technically slightly below the limit for superhydrophobicity

Bioselectivity of silk protein-based materials and their bio-inspired applications

• Hendrik Bargel,
• Vanessa T. Trossmann,
• Christoph Sommer and
• Thomas Scheibel

Beilstein J. Nanotechnol. 2022, 13, 902–921, doi:10.3762/bjnano.13.81

• cells but to even display antiviral attachment properties [58]. Superhydrophobic surfaces inspired by the Lotus-effect® (>150° contact angle) have been found to diminish bacterial adhesion due to reduced protein surface adsorption [59][60][61]. Superhydrophobicity relies on the combination of chemical

Hierachical epicuticular wax coverage on leaves of Deschampsia antarctica as a possible adaptation to severe environmental conditions

• Elena V. Gorb,
• Iryna A. Kozeretska and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2022, 13, 807–816, doi:10.3762/bjnano.13.71

• reduction, or holding air layers at a surface, have been described and their biomimetic applications have been discussed. Phylogenetic trees indicate that superhydrophobicity evolved as a consequence of the conquest of land about 450 million years ago and may be a key innovation in the evolution of

• other words, the liquid should be removed before it freezes to the surface. The superhydrophobicity of the surface might well contribute to such an effect, which has been previously suggested in the literature on bioinspired passive anti-icing and ice-phobic surfaces [36][45]. The present study on D

A comprehensive review on electrospun nanohybrid membranes for wastewater treatment

• Senuri Kumarage,
• Imalka Munaweera and
• Nilwala Kottegoda

Beilstein J. Nanotechnol. 2022, 13, 137–159, doi:10.3762/bjnano.13.10

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

• Sepand Tehrani Fateh,
• Lida Moradi,
• Elmira Kohan,
• Michael R. Hamblin and
• Amin Shiralizadeh Dezfuli

Beilstein J. Nanotechnol. 2021, 12, 808–862, doi:10.3762/bjnano.12.64

Rapid, ultraviolet-induced, reversibly switchable wettability of superhydrophobic/superhydrophilic surfaces

• Yunlu Pan,
• Wenting Kong,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2019, 10, 866–873, doi:10.3762/bjnano.10.87

• superhydrophobic (WCA ≈ 165°) to a superhydrophilic (WCA ≈ 0°) state within 10 min upon UV illumination and subsequent recovery to superhydrophobicity occurred after heat treatment. It was found that the changes in the trimethoxy(alkyl)silane upon UV illumination can explain the rapid decrease of the WCA from more

• illumination can be confirmed. It was found that the presence of trimethoxy(alkyl)silane in the TiO2–trimethoxy(alkyl)silane coating served to speed up the super-wettability transition time from superhydrophobicity to superhydrophilicity, but also limited the number of wettability recycle times. With this

• could be used to induce the property of switchable wettability under UV illumination. In order to be useful for many applications, the ability to rapidly switch the wettability from superhydrophobicity to superhydrophilicity is imperative. Several studies based on TiO2 have been carried out to prepare

Novel reversibly switchable wettability of superhydrophobic–superhydrophilic surfaces induced by charge injection and heating

• Xiangdong Ye,
• Junwen Hou and
• Dongbao Cai

Beilstein J. Nanotechnol. 2019, 10, 840–847, doi:10.3762/bjnano.10.84

• superhydrophobicity and superhydrophilicity has attracted widespread interest because of its important applications. In this work, we propose a reversible superhydrophobic–superhydrophilic conversion induced by charge injection and heating. Different from the conventional electrowetting phenomenon caused by the

• superhydrophilic by charge injection and heating, and the superhydrophobicity was restored by heating, verifying a reversible superhydrophobic–superhydrophilic conversion. The influence of voltage, temperature, and time on the coating wettability and its durability under reversible conversion have been studied

• . Keywords: charge injection; heating; reversible wettability; superhydrophilic; superhydrophobic; Introduction Surfaces that are capable of reversibly switchable wettability have attracted increasing interest, especially those able to switch between superhydrophobicity and superhydrophilicity, and hence

Biomimetic synthesis of Ag-coated glasswing butterfly arrays as ultra-sensitive SERS substrates for efficient trace detection of pesticides

• Guochao Shi,
• Mingli Wang,
• Yanying Zhu,
• Yuhong Wang,
• Xiaoya Yan,
• Xin Sun,
• Haijun Xu and
• Wanli Ma

Beilstein J. Nanotechnol. 2019, 10, 578–588, doi:10.3762/bjnano.10.59

• , probe molecules can concentrate in a very small area after evaporation, resulting in relatively high SERS sensitivity [19]. Using the superhydrophobicity of the textured Taro leaf, Kumar and co-workers fabricated a novel SERS substrate and achieves a LOD value of 10−11 M for malachite green (MG) [20

Ultraviolet patterns of flowers revealed in polymer replica – caused by surface architecture

• Anna J. Schulte,
• Matthias Mail,
• Lisa A. Hahn and
• Wilhelm Barthlott

Beilstein J. Nanotechnol. 2019, 10, 459–466, doi:10.3762/bjnano.10.45

• multifunctional interface. Many of its functions are determined not only by its chemical composition, but also by its surface micro- and nanoarchitecture. Superhydrophobicity [1] is the classical example which can occur even on a chemically hydrophilic surface. Not only is the wettability important, but it must

Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations

• Jaison Jeevanandam,
• Ahmed Barhoum,
• Yen S. Chan,
• Alain Dufresne and
• Michael K. Danquah

Beilstein J. Nanotechnol. 2018, 9, 1050–1074, doi:10.3762/bjnano.9.98

• most famous nanostructure property in plants is the superhydrophobicity in lotus leaves that helps in self-cleaning and super-wettability of the leaves [193]. Many studies in the literature have suggested that stacks of nanostructures are responsible for the circular layer in plants and insects which

Kinetics of solvent supported tubule formation of Lotus (Nelumbo nucifera) wax on highly oriented pyrolytic graphite (HOPG) investigated by atomic force microscopy

• Sujit Kumar Dora,
• Kerstin Koch,
• Wilhelm Barthlott and
• Klaus Wandelt

Beilstein J. Nanotechnol. 2018, 9, 468–481, doi:10.3762/bjnano.9.45

• superhydrophobicity of the wax coated surface. The time and temperature related formation of wax tubules has also been used to develop first artificial Lotus leaves for various wetting studies [24]. However, there are still a number of other factors that can affect tubule growth on HOPG. For example, the

Surfactant-induced enhancement of droplet adhesion in superhydrophobic soybean (Glycine max L.) leaves

• Oliver Hagedorn,
• Ingo Fleute-Schlachter,
• Hans Georg Mainx,
• Viktoria Zeisler-Diehl and
• Kerstin Koch

Beilstein J. Nanotechnol. 2017, 8, 2345–2356, doi:10.3762/bjnano.8.234

• large influence on the wettability, significantly more so than the chemical composition of the waxes [42]. In vitro studies with wax crystals of different sizes and densities showed that superhydrophobicity requires wax crystal sizes of 400 nm in the case of wax tubules [42] and about 200 nm in the case

Collembola cuticles and the three-phase line tension

• Håkon Gundersen,
• Hans Petter Leinaas and
• Christian Thaulow

Beilstein J. Nanotechnol. 2017, 8, 1714–1722, doi:10.3762/bjnano.8.172

• . clavatus does not have overhanging surface structures. This large change in observed contact angles can be explained with a modest change of the three-phase line tension. Keywords: springtails (Collembola); superhydrophobicity; three-phase line tension; Introduction Collembola, a group of small

When the going gets rough – studying the effect of surface roughness on the adhesive abilities of tree frogs

• Niall Crawford,
• Thomas Endlein,
• Jonathan T. Pham,
• Mathis Riehle and
• W. Jon P. Barnes

Beilstein J. Nanotechnol. 2016, 7, 2116–2131, doi:10.3762/bjnano.7.201

• twigs [50]. We are thus building up a good understanding of both the underlying mechanisms and the ecology of tree frog adhesive mechanisms. But this study goes further: comparable to the drag reduction mechanisms of snake skin [51], the superhydrophobicity and self-cleaning mechanisms of lotus leaves

Surface roughness rather than surface chemistry essentially affects insect adhesion

• Matt W. England,
• Tomoya Sato,
• Makoto Yagihashi,
• Atsushi Hozumi,
• Stanislav N. Gorb and
• Elena V. Gorb

Beilstein J. Nanotechnol. 2016, 7, 1471–1479, doi:10.3762/bjnano.7.139

• attachment of the beetles. Surface roughness was found to be the dominant factor, strongly affecting the attachment ability of the beetles. Keywords: insect attachment; superhydrophilicity; superhydrophobicity; superoleophobicity; surface structures; Introduction The development of functional coatings that

• artificially mimic the properties of surfaces found in nature [1][2][3][4] to produce exceptional wetting/dewetting properties, such as superhydrophobicity, superhydrophilicity, and superoleophobicity (more commonly known as superamniphobicity or superomniphobicity), has been a major topic for research over

• commercially available superhydrophobic coating system, which was also used to prepare a rough superhydrophilic surface, by subjecting it to vacuum UV (VUV) light treatment. A superomniphobic surface (defined here as a surface exhibiting both superhydrophobicity and superoleophobicity) was created using candle

Nanostructured superhydrophobic films synthesized by electrodeposition of fluorinated polyindoles

• Gabriela Ramos Chagas,
• Thierry Darmanin and
• Frédéric Guittard

Beilstein J. Nanotechnol. 2015, 6, 2078–2087, doi:10.3762/bjnano.6.212

• allow one to obtain more easily superhydrophobic properties with higher robustness [13][14][15]. Controlling the surface energy and the roughness is hence fundamental to achieve the superhydrophobicity. All kind of materials can be used to reach superhydrophobicity, but conducting polymers have many

• superhydrophobicity of PIndole-6-F6, for example. Here, the presence of a high amount of air between the droplet and the substrate can lead to extremely high θwater with a very low H. In the case of PIndole-6-F6, the presence of the spherical nanoparticles formed on the surface during the polymerization allows to

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

• structured, superhydrophobic, self-cleaning plant surfaces (Lotus-effect) [1][2] there has been an increasing interest in superhydrophobic surfaces [3][4][5]. Superhydrophobicity describes the extreme repellence of water by a surface. The level of water repellence is usually described by the contact angle

• superhydrophobicity can only be achieved by a combination of a hydrophobic surface chemistry and surface structures on the micro and nano scale [11]. On these structured surfaces superhydrophobicity can occur either in the fully wetted state as described by Wenzel [12] or in the form of water sitting only on the tips

• low tilting angles. However for true and persisting superhydrophobicity the Cassie wetting state has to be stable, i.e., no wetting transitions should occur [17][18]. One effective solution to prevent wetting transitions are surfaces with multiscale roughness [19][20][21]. Recently potential

The surface microstructure of cusps and leaflets in rabbit and mouse heart valves

• Xia Ye,
• Bharat Bhushan,
• Ming Zhou and
• Weining Lei

Beilstein J. Nanotechnol. 2014, 5, 622–629, doi:10.3762/bjnano.5.73

• decade due to advancements in nano- and biotechnologies. After millions of years of evolution and optimization, the surfaces of many organisms have formed a variety of special micro- and nanoscale hierarchical structures. These structures show many perfect characteristics such as superhydrophobicity, low

• microstructures of the water skipper’s leg, the moth’s eye, shark skin, the darkling beetle, and the cicada’s wing [6][7][8][9][10][11][12][13][14][15]. At the same time, the relationship between superhydrophobicity and surface microstructures attracted strong interest. A large number of surfaces with all kinds

• . According to Adamson and Gast [27], a model of the relationship between superhydrophobicity and the hierarchical structure could be created. Since the hierarchical structure on the surface of a valve is so similar to the fractal structure described by the Koch curve [28], the fractal structure equation can

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

• post-treatment can reverse the phenomenon. It totally removes the grafted groups and re-establishes the hydrophobic character of the sample. They reported the ability to control the VA-CNTs wettability (from superhydrophilicity to superhydrophobicity) by combining both techniques. The change in the

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

• post surface can not be called “truly” superhydrophobic; indeed, the oxymoron “sticky superhydrophobic” coined by Gao et al. [17] is more appropriate. The fact that composite wetting does not equal superhydrophobicity is illustrated in Figure 1c: In the experiment that is shown, a tilting angle of 90

• hysteresis. For solid fractions equal to and below values of around 10%, the CA hysteresis drops below 5° once post sizes around 1 μm are reached. For these surfaces, very low roll-off angles (below 5°) were observed. In the present work, this behavior is defined as “true” superhydrophobicity. The

Dynamics of capillary infiltration of liquids into a highly aligned multi-walled carbon nanotube film

• Sławomir Boncel,
• Krzysztof Z. Walczak and
• Krzysztof K. K. Koziol

Beilstein J. Nanotechnol. 2011, 2, 311–317, doi:10.3762/bjnano.2.36

• general theory of capillarity can be applied in a prediction of both wettability of HACNT films and the dynamics of capillary rise in the intertube space in various technological applications. Keywords: capillary action; dynamic viscosity; highly aligned carbon nanotubes; superhydrophobicity; wettability

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