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

• production technologies allow for application-specific modification to develop adjustable, bioactive materials as shown in this review article. In the paper "Design of a biomimetic, small-scale artificial leaf surface for the study of environmental interactions" by Huth et al. [10], the authors developed wax

Design of a biomimetic, small-scale artificial leaf surface for the study of environmental interactions

• Miriam Anna Huth,
• Axel Huth,
• Lukas Schreiber and
• Kerstin Koch

Beilstein J. Nanotechnol. 2022, 13, 944–957, doi:10.3762/bjnano.13.83

• composition play significant roles. Here, the ability of self-assembly of wax after isolation from the leaves was used to develop a small-scale wax-coated artificial leaf surface with the chemical composition and wettability of wheat (Triticum aestivum) leaves. By thermal evaporation of extracted plant waxes

• wetting properties of a natural leaf surface. Keywords: recrystallization; surface properties; wax composition; wetting; wheat; Introduction Cuticle One of the largest interfaces on earth is formed by thin layers that are a few nanometers to micrometers thin, namely the wax layers of the plant cuticle

• ), so that a homogeneous distribution of the wax masses can be achieved [42]. Aim of this study In the present study, the wettability and chemical character of a natural leaf surface were transferred to technical surfaces by the process of PVD. Wheat, one of the most important crops worldwide, served as

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

• the plant species studied, the epicuticular wax coverage has been previously shown (using SEM) and described only on one (adaxial) leaf lamina side [9], where small strands prostrate on each other forming a dense tangle on the entire leaf surface including stomata, whereas the abaxial side lacks the

• wax coverage. A dense wax coverage on the adaxial leaf surface was later alluded to by Kyryachenko et al. [6] based on the work of Romero and co-workers [10]. However, the latter authors [10] have not referred to the wax, which is nevertheless seen on the SEM images. Also in a more recent review on

Polarity in cuticular ridge development and insect attachment on leaf surfaces of Schismatoglottis calyptrata (Araceae)

• Venkata A. Surapaneni,
• Tobias Aust,
• Thomas Speck and
• Marc Thielen

Beilstein J. Nanotechnol. 2021, 12, 1326–1338, doi:10.3762/bjnano.12.98

• ][6]. The cuticular structures together with the epidermal cell shape and the cuticle chemistry provide the leaf surface with multiple functions [7]. In particular, cuticular ridges on some leaf surfaces have been found to reduce the frictional forces of insects during walking and may increase the

• rolled-up at this stage, the ontogenetic stage was defined based on an arbitrarily chosen leaf age, namely five days from bud formation. Stage 2 leaves had cuticular ridges covering half (50 ± 10%) of the leaf surface. This was subdivided into stage 2A representing the area toward the apex of the leaves

• completed. Surface replication and characterization Replication of the leaf surface was carried out using a two-step molding approach (Epoxy-PDMS) as described in Kumar et al. [46] and Surapaneni et al. [23], except that the entire adaxial leaf surfaces of S. calyptrata (leaf area: 15–293 cm2) were

Self-assembly of Eucalyptus gunnii wax tubules and pure ß-diketone on HOPG and glass

• Miriam Anna Huth,
• Axel Huth and
• Kerstin Koch

Beilstein J. Nanotechnol. 2021, 12, 939–949, doi:10.3762/bjnano.12.70

• tubules in nature. On E. gunnii leaves, wax regeneration can be observed by AFM, but the measurement is limited to small areas and short times due to the roughness of the leaf surface [30]. In addition, fresh plant leaves containing water are heated by the laser beam during scanning, which can cause a

• understanding of the architecture and formation of these protective surface structures frequently found in plants. SEM micrograph of ß-diketone tubules on an E. gunnii leaf surface. Scale bar 400 nm. SEM micrographs of wax and ß-diketone recrystallized on HOPG and glass after three days. Left column: wax

Biomimetic surface structures in steel fabricated with femtosecond laser pulses: influence of laser rescanning on morphology and wettability

• Camilo Florian Baron,
• Alexandros Mimidis,
• Daniel Puerto,
• Evangelos Skoulas,
• Emmanuel Stratakis,
• Javier Solis and
• Jan Siegel

Beilstein J. Nanotechnol. 2018, 9, 2802–2812, doi:10.3762/bjnano.9.262

• surface structures; laser rescanning; steel; wettability; Introduction Complex structures found in nature often present properties that are attractive for applications in science and technology. The hydrophobicity found at the lotus leaf surface [1], the exceptional adhesion capability of gecko feet [2

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

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

• . Studies with hygroscopic salt particles, e.g., ammonium sulphate salts, in contact with leaf waxes showed that waxes move from the leaf surface and grow over the salt particles (Burkhardt et al. [26]). This observed transport of wax was also assigned to a co-transport with water onto the hygroscopic salt

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

• Ecophysiology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany 10.3762/bjnano.8.234 Abstract This study performed with soybean (Glycine max L.), one of the most important crops for human and animal nutrition, demonstrates that changes in the leaf surface structure can increase the adhesion of

• and five variations of nonionic surfactants) have been investigated. The leaf surface structures show a hierarchical organization, built up by convex epidermal cells (microstructure) and superimposed epicuticular platelet-shaped wax crystals (micro- to nanostructure). Chemical analysis of the

• roll off. Droplet adhesion can be improved by adding adjuvants, such as surfactants. Surfactants enhance the leaf surface wettability by reduction of the surface tension of applied liquids. Surfactants are amphiphilic molecules with a nonpolar, hydrophobic structural group together with a hydrophilic

Biological and biomimetic materials and surfaces

• Stanislav Gorb and
• Thomas Speck

Beilstein J. Nanotechnol. 2017, 8, 403–407, doi:10.3762/bjnano.8.42

• (Nelumbo nucifera) and Tropaeolum (Tropaeolum majus). Interestingly, with the rolling off of water droplets, dirt particles as well as fungus spores and bacteria are also very efficiently removed from the leaf surfaces as they are more tightly attached to the water droplet than to the leaf surface. The

• few contact points to the leaf surface which has a micro-/nanoscale roughness. The same holds for the water droplets which become spherical for energetic reasons and cannot wet the leaf surface [1][2][3]. The discovery of this phenomenon and its structural basis dates back to the 1970s when Wilhelm

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

• ]. However, recent studies on insect attachment have yielded contradicting results. For example, a previous experimental study on attachment of the beetle Gastrophysa viridula to the leaf surface of its host plant Rumex obtusifolius, and artificial micro-roughened and smooth (hydrophobic and hydrophilic

• and experimental designs were used. In some of these studies, insect species that are strongly specialized to host plants whose leaf surfaces have very specific surface energies (water CA about 80°), such as the beetle Galerucella nympheae which lives on the leaf surface of the water lily, the maximum

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

• submerged to fast. Air volumes on Salvinia leaves The air volumes held by four different Salvinia species were more variable due to the more complex surface microstructure (see Figure 4) and great differences in leaf surface area which ranged from 44 ± 8 mm2 for S. minima up to 1388 ± 149 mm2 for S

• . oblongifolia (S. cucullata: 224 ± 23 mm2, S. molesta 359 ± 52 mm2). For better comparability of the different species we normalised the measured air volumes with the leaf surface area (Figure 2). In order to test whether the leaf surface area has an influence on the air volume per surface area we performed a

• leaf surface area on the air volume per surface area could not be found. As the trichomes decrease in height towards the leaf edges, the air volume per leaf area also decreases towards the leaf edges. Idealising a leaf as a circle, the edge length (circumference) rises linearly with radius (C = 2πr

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

• water and the leaf surface is thereby minimized [1]. This micro- and nanostructured surface, composed of low surface energy materials, leads to a high CA (163°) and a low hysteresis and tilt angle (2–3°). Additionally, lotus leaves show low adhesive properties to adhering particles. Thus, contamination

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

• lower epidermis. The lotus plant has successfully developed an excellent protection for this delicate epistomatic surface of its leaves. Keywords: epicuticular wax; leaf surface; Lotus effect; papillae; water repellency; Introduction Since the introduction of the ‘Lotus concept’ in 1992 [1][2], the

• -scanning electron microscopy demonstrated the extremely reduced contact area for lotus [12]. Zhang et al. (2008) [13] made detailed measurements of the water repellency of the papillose lotus leaf surface in comparison with the non-papillose leaf margin. The importance of the nanoscopic wax crystals for

• the ability to protect the leaf surface in lotus is the robustness of its leaf papillae in combination with their high density. Cross sections (Figure 9) show that they are almost massive at least in the apical part, in contrast to the fragile papillose cells found on many flower petals. However

Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

• Bharat Bhushan

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

• used in micro/nanofluidics, it is desirable to minimize the drag force at the solid–liquid interface. A model surface for superhydrophobicity, self-cleaning and low adhesion is the leaves of water-repellent plants such as Nelumbo nucifera (lotus) [2][4][5][6][7][8][9][10][11]. The leaf surface is very