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

• “Purity of the sacred lotus” [1] in which they described the superhydrophobic surfaces and the self-cleaning ability of some plants (the so-called “lotus effect”, see Figure 1). This paper led to a paradigm shift in surface sciences. It generated a lot of interest at the time and continues today to

• actual applications. This was also the case with the lotus effect. Biomimetics was finally given a name in the second half of the last century, interestingly just as humankind was finally achieving Icarus’s dream of flying closer to the sun. The big push in the field came with the rapid development of

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

• Holzgerlingen, Germany 10.3762/bjnano.13.113 Abstract Superhydrophobic surfaces are well known for most different functions in plants, animals, and thus for biomimetic technical applications. Beside the Lotus Effect, one of their features with great technical, economic and ecologic potential is the Salvinia

• ] and is known for more than thousand years [3], but after the Lotus effect publication [4], this research led to a paradigm shift in surface science [5] and was the starting point for novel technologies in surface science [5]. Today many products in forms of coatings, sprays and paints providing

Straight roads into nowhere – obvious and not-so-obvious biological models for ferrophobic surfaces

• Wilfried Konrad,
• Christoph Neinhuis and
• Anita Roth-Nebelsick

Beilstein J. Nanotechnol. 2022, 13, 1345–1360, doi:10.3762/bjnano.13.111

• which a suitable biological model is sought. The “Lotus effect” belongs to the first class. It was identified by Wilhelm Barthlott and suggested (later accompanied by one of the co-authors, C. Neinhuis) as relevant for surface technology. The highly water-repellent plant cuticles, which are equipped

• with hierarchically structured wax crystals, would represent “ready-made” models of superhydrophobic surfaces with versatile technical applications. The Lotus effect indeed proved to be attractive for applied sciences (as this special issue demonstrates), and its underlying physics was thoroughly

• water spider or the floating fern Salvinia molesta (and other Salvinia species), and their surfaces have an appearance similar to that of terrycloth. Both the Lotus effect and the surfaces with stay-dry-under-water potential became – after their introduction into biomimetics – popular items for the top

Growing up in a rough world: scaling of frictional adhesion and morphology of the Tokay gecko (Gekko gecko)

• Anthony J. Cobos and
• Timothy E. Higham

Beilstein J. Nanotechnol. 2022, 13, 1292–1302, doi:10.3762/bjnano.13.107

• the Lotus Effect [11], the Gecko Effect has seen a surge in attention over the past couple of decades [12]. There are over 1000 species of geckos with adhesive capabilities, with multiple origins of the system [13][14]. However, much of what is known about gecko adhesion and its associated structures

Laser-processed antiadhesive bionic combs for handling nanofibers inspired by nanostructures on the legs of cribellate spiders

• Sebastian Lifka,
• Kristóf Harsányi,
• Erich Baumgartner,
• Lukas Pichler,
• Dariya Baiko,
• Karsten Wasmuth,
• Johannes Heitz,
• Marco Meyer,
• Anna-Christin Joel,
• Jörn Bonse and
• Werner Baumgartner

Beilstein J. Nanotechnol. 2022, 13, 1268–1283, doi:10.3762/bjnano.13.105

• interaction and, thus, the design of a suitable surface structure to prevent sticking of an artificially nonwoven of nanofibers. Similar to the description of the Lotus effect [20][21][22][23], where the wettability of the hierarchical surface structure of the lotus leaf can be described with an energy

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

• fabricate such a surface featuring the lotus effect, solely through structuring, is hot pulling of a polymer surface. This technique provides the so-called nanofur, which consists of a polymer surface densely covered with a polymeric fur of extremely thin hair-like structures. Here, we present a continuous

• . 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

• unwanted dirt [5][6]. The lotus effect is commonly achieved by hierarchical nano- and micro-structuring of surfaces made from materials with low surface energy leading to very high contact angles (above 150°). This strategy is inspired by the lotus leaf [1] but can be found on many other surfaces in nature

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

• inclined plane. The angle of inclination at which a droplet starts to roll off is called the TA α. Superhydrophobic surfaces with a low TA (α < 10°) and a small CAH have the ability to self-clean [9]. This property is also known as the Lotus effect, named after the best-known example of a self-cleaning

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

• ., Asclepiadaceae and Cactaceae) [15], plays a crucial role in the protection from water loss. Biomimetic potential Since the discovery of the lotus effect [43], different properties of superhydrophobic surfaces in plants, which are highly relevant for modern technologies, such as self-cleaning, fluid drag

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

• structure [13][18]. Secondary alcohol tubules evolved in all major groups of land plants and design durable superhydrophobic surfaces (e.g., the Lotus Effect). In vitro recrystallization experiments with single wax components of these tubules showed that tubules were formed by secondary alcohols plus at

Air–water interface of submerged superhydrophobic surfaces imaged by atomic force microscopy

• Markus Moosmann,
• Thomas Schimmel,
• Wilhelm Barthlott and
• Matthias Mail

Beilstein J. Nanotechnol. 2017, 8, 1671–1679, doi:10.3762/bjnano.8.167

• effect; Introduction Air retention is one of the many fascinating aspects of superhydrophobic surfaces, offering promising new capabilities for technical applications [1]. Starting with the discovery of the lotus effect in 1997 [2], new fields in surface technology have been realized [3][4]. In recent

Biological and biomimetic materials and surfaces

• Stanislav Gorb and
• Thomas Speck

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

• , Germany, Freiburg Institute for Interactive Materials & Bioinspired Technologies (FIT), 79104 Freiburg, Germany 10.3762/bjnano.8.42 Keywords: adhesion; bio-inspired materials; biomimetics; interfaces; lotus effect; surfaces; This Thematic Series is a tribute to Wilhem Barthlott, a famous German botanist

• some biomimetic products, for example, the facade paint Lotusan® produced by Sto SEA Pte. [7] or the product Tegotop® 210 from Evonik Industries AG. The products are sold under the brand name Lotus-Effect® which has become a near synonym for functional, water-repellent surfaces in general. Without

• exaggeration one can say that Lotus-Effect® surfaces, together with fasteners inspired by gecko attachment structures, can be considered as “flagships” of contemporary surface-related biomimetic research. Still today questions related to these effects are the topic of novel state-of-the-art studies in the

Innovations from the “ivory tower”: Wilhelm Barthlott and the paradigm shift in surface science

• Christoph Neinhuis

Beilstein J. Nanotechnol. 2017, 8, 394–402, doi:10.3762/bjnano.8.41

• in materials science. Keywords: Wilhelm Barthlott; 70th birthday; self-cleaning surfaces; lotus-effect; Separation Most obviously, borders are meant to separate two or more entities from another (Figure 1). It might be our atmosphere separating us from space, an ocean separating two continents, a

• , self-cleaning surfaces nowadays are well known. The transfer and technical application have received several awards and the trademark “Lotus-Effect” has become a kind of synonym for functional water-repellent or even only hydrophobic surfaces. Follow-up investigations have been published in all major

The cleaner, the greener? Product sustainability assessment of the biomimetic façade paint Lotusan^® in comparison to the conventional façade paint Jumbosil^®

• Florian Antony,
• Rainer Grießhammer,
• Thomas Speck and
• Olga Speck

Beilstein J. Nanotechnol. 2016, 7, 2100–2115, doi:10.3762/bjnano.7.200

• -cycle assessment (LCA); Lotus-Effect® technology; Lotusan®; product sustainability assessment (PROSA); Introduction In-depth analyses of functions found in biology and the systematic transfer of the respective operating principles into technical applications is the essential aim of biomimetics [1][2

• realization, at least as a prototype, is the third and final criterion [13]. The result, the technical application of self-cleaning properties is what became well known as the lotus effect. The patent application was submitted on 25th July 1995 and granted by the German Patent and Trademark Office on February

• 4th in 1999 [8]. Sto SE & Co. KGaA (79780 Stühlingen, Germany) acquired the patent rights in 2009 and holds the trademark „Lotus-Effect®“. The fact that the façade paint Lotusan® is available on the market since the late 1990s might be seen as a sufficient argument for the existence of a technical

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

• properties, characterized by extremely high water contact angles (θw) and low water adhesion or hysteresis (also known as “Lotus effect”), grows exponentially because of the importance for both the scientific and industrial community [1][2][3][4][5][6]. Superhydrophobic properties are quite common in nature

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

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

• also by polymer functionalization. Lau et al. [131] favored a bio-inspired approach to the problem and mimicked designs found in nature. In certain plants such as the lotus leaf, water droplets roll on the surface and remove dust particles; this is a self-cleaning behavior and is called the Lotus

• effect [132]. The origin is the peculiar roughness and the intrinsic hydrophobic behavior of the surface. Based on this observation, the authors enhanced the superhydrophobic effect on CNTs by combining two elements: the coating of VA-CNTs with hydrophobic poly(tetrafluoroethylene) (PTFE) and the

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

• (“Lotus effect”) [4][5][6] or cause air retention under water (“Salvinia effect”) [7][8]. Superhydrophobic, self-cleaning surfaces possess a static contact angle (CA) equal to or above 150°, and a low hysteresis angle, where water droplets roll-off at surface inclinations equal to or below 10° [6][9]. One

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

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

• 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

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

• world [5][6]. The effective self-cleaning mechanism of the Lotus flower Nelumbo nucifera is especially well known [3]. Granting of a patent in 1998 [7], followed by the introduction of the trade mark Lotus-Effect® was the start of the realisation of biomimetic self-cleaning surfaces. Another highly

Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

• Bharat Bhushan

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

• biomimetic artificial surfaces with either low drag or self-cleaning/anti-fouling properties. Two examples from nature: (a) Lotus effect [12], and (b) scale structure of shark reducing drag [21]. Schematic of velocity profiles of fluid flow without and with boundary slip. The definition of slip length b

Beilstein Journal of Nanotechnology

• Thomas Schimmel

Beilstein J. Nanotechnol. 2010, 1, 1–2, doi:10.3762/bjnano.1.1

• and technologies. Nano-photonics, quantum electronics, the lotus effect and the fascinating properties of graphene are only a few well-known examples. The Beilstein Journal of Nanotechnology provides a platform for the effective exchange and dissemination of cutting-edge results in the broad area of