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Rodríguez S, Rocha J, Fernandes M, Ravishankar AP, Steinbrück N, Cruz R, Bacelar E, Kickelbick G, Anand S, Crespí AL, Casal S, de Zea Bermudez V. The Surfaces of the Ceratonia siliqua L. (Carob) Leaflet: Insights from Physics and Chemistry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2011-2028. [PMID: 33533623 DOI: 10.1021/acs.langmuir.0c02806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The production of superhydrophobic coatings inspired by the surface of plant leaves is a challenging goal. Such coatings hold a bright technological future in niche markets of the aeronautical, space, naval, building, automobile, and biomedical sectors. This work is focused on the adaxial (top) and abaxial (bottom) surfaces of the leaflet of the Ceratonia silique L. (carob), a high-commercial-value Mediterranean tree cultivated in many regions of the world. The adaxial and abaxial surfaces feature hydrophobic and superhydrophobic behaviors, respectively. Their chemical composition is very simple: monopalmitin ester and palmitic acid are protuberant in the epicuticular and intracuticular wax layers of the adaxial surface, respectively, whereas 1-octacosanol dominates in the abaxial wax layers. In both surfaces, epicuticular wax is organized along a randomly oriented and intricate network of nanometer-thick and micrometer-long plates, whose density and degree of interconnection are significantly higher in the abaxial surface. The measured tilting angles for the abaxial surface (12-70°) reveal unusual variable density and water adhesion of the nanostructured plate-based texture. Optical measurements demonstrate that light reflectance/absorbance of the glaucous abaxial surface is significantly higher/lower than that of the nonglaucous adaxial surface. In both surfaces, diffuse reflectance is dominant, and the absorbance is weakly dependent on the light incidence angle. We show that the highly dense nanostructured platelike texture of the epicuticular abaxial layer of the C. siliqua leaflet works as a sophisticated light and water management system: it reflects solar radiation diffusely to lower the surface temperature, and it has superhydrophobic character to keep the surface dry. Such attributes enable efficient gas exchange (photosynthesis and respiration), transpiration, and evaporation. To mimic for the first time the abaxial surface, a templation approach was adopted using poly(dimethylsiloxane) (PDMS)/poly(methylphenylsiloxane) (PMPS) positive/negative replicas and a soft polymer/siloxane negative replica produced by the sol-gel process. Because high topographical variations of the biotemplate and wax adhesion to the biohybrid film affected the replication quality, the reproduction of the wax texture via the synthesis of 1-octacosanol-grafted siloxane-based hybrid materials is proposed as a suitable route to duplicate the abaxial surface with high fidelity. The natural chemical/physical strategy adopted by the C. siliqua leaflet to face the harsh Mediterranean climate is a powerful source of bioinspiration for the development of diffuse reflecting and superhydrophobic material systems with foreseen applications as dual-functional antiglare and water-repelling coatings.
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Affiliation(s)
- S Rodríguez
- CQ-VR, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
| | - J Rocha
- CQ-VR, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
- Herbarium and Botanical Garden, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
| | - M Fernandes
- CQ-VR, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
- Department of Chemistry, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
| | - A P Ravishankar
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Albanova University Centre, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden
| | - N Steinbrück
- Inorganic Solid State Chemistry, Saarland University, Campus Building C4 1, 66123 Saarbrücken, Germany
| | - R Cruz
- LAQV-REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, Laboratory of Bromatology and Hydrology, University of Porto, 4050-313 Porto, Portugal
| | - E Bacelar
- CITAB, Department of Biological and Environmental Engineering, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
| | - G Kickelbick
- Inorganic Solid State Chemistry, Saarland University, Campus Building C4 1, 66123 Saarbrücken, Germany
| | - S Anand
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Albanova University Centre, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden
| | - A L Crespí
- Herbarium and Botanical Garden, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
- CITAB, Department of Biological and Environmental Engineering, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
| | - S Casal
- LAQV-REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, Laboratory of Bromatology and Hydrology, University of Porto, 4050-313 Porto, Portugal
| | - V de Zea Bermudez
- CQ-VR, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
- Department of Chemistry, University of Trás-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal
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Fritz B, Horváth G, Hünig R, Pereszlényi Á, Egri Á, Guttmann M, Schneider M, Lemmer U, Kriska G, Gomard G. Bioreplicated coatings for photovoltaic solar panels nearly eliminate light pollution that harms polarotactic insects. PLoS One 2020; 15:e0243296. [PMID: 33270747 PMCID: PMC7714120 DOI: 10.1371/journal.pone.0243296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/19/2020] [Indexed: 12/04/2022] Open
Abstract
Many insect species rely on the polarization properties of object-reflected light for vital tasks like water or host detection. Unfortunately, typical glass-encapsulated photovoltaic modules, which are expected to cover increasingly large surfaces in the coming years, inadvertently attract various species of water-seeking aquatic insects by the horizontally polarized light they reflect. Such polarized light pollution can be extremely harmful to the entomofauna if polarotactic aquatic insects are trapped by this attractive light signal and perish before reproduction, or if they lay their eggs in unsuitable locations. Textured photovoltaic cover layers are usually engineered to maximize sunlight-harvesting, without taking into consideration their impact on polarized light pollution. The goal of the present study is therefore to experimentally and computationally assess the influence of the cover layer topography on polarized light pollution. By conducting field experiments with polarotactic horseflies (Diptera: Tabanidae) and a mayfly species (Ephemeroptera: Ephemera danica), we demonstrate that bioreplicated cover layers (here obtained by directly copying the surface microtexture of rose petals) were almost unattractive to these species, which is indicative of reduced polarized light pollution. Relative to a planar cover layer, we find that, for the examined aquatic species, the bioreplicated texture can greatly reduce the numbers of landings. This observation is further analyzed and explained by means of imaging polarimetry and ray-tracing simulations. The results pave the way to novel photovoltaic cover layers, the interface of which can be designed to improve sunlight conversion efficiency while minimizing their detrimental influence on the ecology and conservation of polarotactic aquatic insects.
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Affiliation(s)
- Benjamin Fritz
- Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Gábor Horváth
- Environmental Optics Laboratory, Department of Biological Physics, ELTE Eötvös Loránd University, Budapest, Hungary
- * E-mail:
| | - Ruben Hünig
- Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW), Stuttgart, Germany
| | - Ádám Pereszlényi
- Environmental Optics Laboratory, Department of Biological Physics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Ádám Egri
- MTA Centre for Ecological Research, Danube Research Institute, Budapest, Hungary
- MTA Centre for Ecological Research, Evolutionary Systems Research Group, Tihany, Hungary
| | - Markus Guttmann
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Marc Schneider
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Uli Lemmer
- Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - György Kriska
- MTA Centre for Ecological Research, Danube Research Institute, Budapest, Hungary
- Group for Methodology in Biology Teaching, Biological Institute, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Guillaume Gomard
- Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
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Bauer U, Poppinga S, Müller UK. Mechanical Ecology-Taking Biomechanics to the Field. Integr Comp Biol 2020; 60:820-828. [PMID: 32275745 DOI: 10.1093/icb/icaa018] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Synopsis Interdisciplinary research can have strong and surprising synergistic effects, leading to rapid knowledge gains. Equally important, it can help to reintegrate fragmented fields across increasingly isolated specialist sub-disciplines. However, the lack of a common identifier for research "in between fields" can make it difficult to find relevant research outputs and network effectively. We illustrate and address this issue for the emerging interdisciplinary hotspot of "mechanical ecology," which we define here as the intersection of quantitative biomechanics and field ecology at the organism level. We show that an integrative approach crucially advances our understanding in both disciplines by (1) putting biomechanical mechanisms into a biologically meaningful ecological context and (2) addressing the largely neglected influence of mechanical factors in organismal and behavioral ecology. We call for the foundation of knowledge exchange platforms such as meeting symposia, special issues in journals, and focus groups dedicated to mechanical ecology.
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Affiliation(s)
- Ulrike Bauer
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Simon Poppinga
- Plant Biomechanics Group, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany.,Freiburg Materials Research Center (FMF), University of Freiburg, Freiburg im Breisgau, Germany
| | - Ulrike K Müller
- Department of Biology, California State University Fresno, Fresno, CA, USA
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Kraaij M, van der Kooi CJ. Surprising absence of association between flower surface microstructure and pollination system. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:177-183. [PMID: 31710761 PMCID: PMC7064994 DOI: 10.1111/plb.13071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/03/2019] [Indexed: 05/25/2023]
Abstract
The epidermal cells of flowers come in different shapes and have different functions, but how they evolved remains largely unknown. Floral micro-texture can provide tactile cues to insects, and increases in surface roughness by means of conical (papillose) epidermal cells may facilitate flower handling by landing insect pollinators. Whether flower microstructure correlates with pollination system remains unknown. Here, we investigate the floral epidermal microstructure in 29 (congeneric) species pairs with contrasting pollination system. We test whether flowers pollinated by bees and/or flies feature more structured, rougher surfaces than flowers pollinated by non-landing moths or birds and flowers that self-pollinate. In contrast with earlier studies, we find no correlation between epidermal microstructure and pollination system. The shape, cell height and roughness of floral epidermal cells varies among species, but is not correlated with pollinators at large. Intriguingly, however, we find that the upper (adaxial) flower surface that surrounds the reproductive organs and often constitutes the floral display is markedly more structured than the lower (abaxial) surface. We thus conclude that conical epidermal cells probably play a role in plant reproduction other than providing grip or tactile cues, such as increasing hydrophobicity or enhancing the visual signal.
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Affiliation(s)
- M. Kraaij
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenthe Netherlands
| | - C. J. van der Kooi
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenthe Netherlands
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Chen J, Fritz B, Liang G, Ding X, Lemmer U, Gomard G. Microlens arrays with adjustable aspect ratio fabricated by electrowetting and their application to correlated color temperature tunable light-emitting diodes. OPTICS EXPRESS 2019; 27:A25-A38. [PMID: 30876002 DOI: 10.1364/oe.27.000a25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
We develop a facile, fast, and cost-effective method based on the electrowetting effect to fabricate concave microlens arrays (MLA) with a tunable height-to-radius ratio, namely aspect ratio (AR). The electric parameters including voltage and frequency are demonstrated to play an important role in the MLA forming process. With the optimized frequency of 5 Hz, the AR of MLA are tuned from 0.057 to 0.693 for an increasing voltage from 0 V to 180 V. The optical properties of the MLA, including their transmittance and light diffusion capability, are investigated by spectroscopic measurements and ray-tracing simulations. We show that the overall transmittance can be maintained above around 90% over the whole visible range, and that an AR exceeding 0.366 is required to sufficiently broaden the transmitted light angular distribution. These properties enable to apply the developed MLA films to correlated-color-temperature (CCT)-tunable light-emitting-diodes (LEDs) to enhance their angular color uniformity (ACU). Our results show that the ACU of CCT-tunable LEDs is significantly improved while preserving almost the same lumen output, and that the MLA with the highest AR exhibits the best ACU performance.
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Vüllers F, Fritz B, Roslizar A, Striegel A, Guttmann M, Richards BS, Hölscher H, Gomard G, Klampaftis E, Kavalenka MN. Self-Cleaning Microcavity Array for Photovoltaic Modules. ACS APPLIED MATERIALS & INTERFACES 2018; 10:2929-2936. [PMID: 29284257 DOI: 10.1021/acsami.7b15579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Development of self-cleaning coatings is of great interest for the photovoltaic (PV) industry, as soiling of the modules can significantly reduce their electrical output and increase operational costs. We fabricated flexible polymeric films with novel disordered microcavity array (MCA) topography from fluorinated ethylene propylene (FEP) by hot embossing. Because of their superhydrophobicity with water contact angles above 150° and roll-off angles below 5°, the films possess self-cleaning properties over a wide range of tilt angles, starting at 10°, and contaminant sizes (30-900 μm). Droplets that impact the FEP MCA surface with velocities of the same order of magnitude as that of rain bounce off the surface without impairing its wetting properties. Additionally, the disordered MCA topography of the films enhances the performance of PV devices by improving light incoupling. Optical coupling of the FEP MCA films to a glass-encapsulated multicrystalline silicon solar cell results in 4.6% enhancement of the electrical output compared to that of an uncoated device.
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Affiliation(s)
- Felix Vüllers
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Benjamin Fritz
- Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT) , Engesserstrasse 13, 76131 Karlsruhe, Germany
| | - Aiman Roslizar
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Andreas Striegel
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Markus Guttmann
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Bryce S Richards
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT) , Engesserstrasse 13, 76131 Karlsruhe, Germany
| | - Hendrik Hölscher
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Guillaume Gomard
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT) , Engesserstrasse 13, 76131 Karlsruhe, Germany
| | - Efthymios Klampaftis
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Maryna N Kavalenka
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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