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Singla S, Yang Z, Patil A, Guo H, Vanthournout B, Htut KZ, Shawkey MD, Tsige M, Dhinojwala A. Influence of Core Type and Shell Thickness on Avian-Inspired Structural Colors Produced from Melanin Nanoparticle Assemblies. ACS APPLIED MATERIALS & INTERFACES 2023; 15:45229-45238. [PMID: 37699412 DOI: 10.1021/acsami.3c08152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Hollow melanosomes found in iridescent bird feathers, including violet-backed starlings and wild turkeys, enable the generation of diverse structural colors. It has been postulated that the high refractive index (RI) contrast between melanin (1.74) and air (1.0) results in brighter and more saturated colors. This has led to several studies that have synthesized hollow synthetic melanin nanoparticles and fabricated colloidal nanostructures to produce synthetic structural colors. However, these studies use hollow nanoparticles with thin shells (<20 nm), even though shell thicknesses as high as 100 nm have been observed in natural melanosomes. Here, we combine experimental and computational approaches to examine the influence of the varying polydopamine (PDA, synthetic melanin) shell thickness (0-100 nm) and core material on structural colors. Experimentally, a concomitant change in overall particle size and RI contrast makes it difficult to interpret the effect of a hollow or solid core on color. Thus, we utilize finite-difference time-domain (FDTD) simulations to uncover the effect of shell thickness and core on structural colors. Our FDTD results highlight that hollow particles with thin shells have substantially higher saturation than same-sized solid and core-shell particles. These results would benefit a wide range of applications including paints, coatings, and cosmetics.
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Affiliation(s)
- Saranshu Singla
- School of Polymer Science and Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Zepeng Yang
- School of Polymer Science and Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Anvay Patil
- School of Polymer Science and Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Hao Guo
- School of Polymer Science and Engineering, The University of Akron, Akron, Ohio 44325, United States
| | | | - K Zin Htut
- School of Polymer Science and Engineering, The University of Akron, Akron, Ohio 44325, United States
| | | | - Mesfin Tsige
- School of Polymer Science and Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Ali Dhinojwala
- School of Polymer Science and Engineering, The University of Akron, Akron, Ohio 44325, United States
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Chiera S, Koch VM, Bleyer G, Walter T, Bittner C, Bachmann J, Vogel N. From Sticky to Slippery: Self-Functionalizing Lubricants for In Situ Fabrication of Liquid-Infused Surfaces. ACS APPLIED MATERIALS & INTERFACES 2022; 14:16735-16745. [PMID: 35353481 DOI: 10.1021/acsami.2c02390] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Liquid-infused surfaces offer a versatile approach to create self-cleaning coatings. In such coatings, a thin film of a fluid lubricant homogeneously coats the substrate and thus prevents direct contact with a second, contaminating liquid. For stable repellency, the interfacial energies need to be controlled to ensure that the lubricant is not replaced by the contaminating liquid. Here, we introduce the concept of self-functionalizing lubricants. Functional molecular species that chemically match the lubricant but possess selective anchor groups are dissolved in the lubricant and self-adhere to the surface, forming the required surface chemistry in situ from within the applied lubricant layer. To add flexibility to the self-functionalizing concept, the substrate is first primed with a thin polydopamine base layer, which can be deposited to nearly any substrate material from aqueous solutions and retains reactivity toward electron-donating groups such as amines. The temporal progression of the in situ functionalization is investigated by ellipsometry and quartz crystal microbalance and correlated to macroscopic changes in contact angle and contact angle hysteresis. The flexibility of the approach is underlined by creating repellent coatings with various substrate/lubricant combinations. The prepared liquid-infused surfaces significantly reduce cement adhesion and provide easy-to-clean systems under real-world conditions on shoe soles.
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Affiliation(s)
- Salvatore Chiera
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany
- Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Vanessa M Koch
- Chair 'Chemistry of Thin Film Materials' (CTFM), Friedrich-Alexander University Erlangen-Nürnberg (FAU), IZNF, Cauerstraße 3, 91058 Erlangen, Germany
| | - Gudrun Bleyer
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany
- Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Teresa Walter
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany
- Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Carina Bittner
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany
- Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Julien Bachmann
- Chair 'Chemistry of Thin Film Materials' (CTFM), Friedrich-Alexander University Erlangen-Nürnberg (FAU), IZNF, Cauerstraße 3, 91058 Erlangen, Germany
| | - Nicolas Vogel
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany
- Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058, Germany
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Kohri M. Progress in polydopamine-based melanin mimetic materials for structural color generation. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2021; 21:833-848. [PMID: 33536837 PMCID: PMC7832497 DOI: 10.1080/14686996.2020.1852057] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 05/04/2023]
Abstract
Structural color is a color derived from optical interaction between light and a microstructure and is often seen in nature. Natural melanin plays an important role in bright structural coloration. For example, the vivid colors of peacock feathers are due to structural colors. The periodic arrangement of melanin granules inside the feathers leads to light interference, and the black granules absorb scattered light well, resulting in bright structural color. In recent years, polydopamine (PDA) has attracted attention as a melanin mimetic material. This review article summarizes recent research on structural coloration using PDA-based artificial melanin materials. It also outlines possible applications using bright structural colors realized by artificial melanin materials and future perspectives.
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Affiliation(s)
- Michinari Kohri
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Chiba, Japan
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Nowogrodski C, Simon I, Magdassi S, Shoseyov O. Fabrication of Second Skin from Keratin and Melanin. Polymers (Basel) 2020; 12:polym12112568. [PMID: 33147696 PMCID: PMC7692603 DOI: 10.3390/polym12112568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 12/28/2022] Open
Abstract
Second skin is a topically applied, skin-conforming material that mimics human skin properties and bears potential cosmetic and e-skin applications. To successfully integrate with natural skin, characteristics such as color and skin features must be matched. In this work, we prepared bio-based skin-like films from cross-linked keratin/melanin films (KMFs), using a simple fabrication method and non-toxic materials. The films retained their stability in aqueous solutions, showed skin-like mechanical properties, and were homogenous and handleable, with non-granular surfaces and a notable cross-linked structure as determined by attenuated total reflection (ATR). In addition, the combination of keratin and melanin allowed for adjustable tones similar to those of natural human skin. Furthermore, KMFs showed light transmittance and UV-blocking (up to 99%) as a function of melanin content. Finally, keratin/melanin ink (KMI) was used to inkjet-print high-resolution images with natural skin pigmented features. The KMFs and KMI may offer advanced solutions as e-skin or cosmetics platforms.
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Affiliation(s)
- Chen Nowogrodski
- Plant Molecular Biology and Nano Biotechnology, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (I.S.); (O.S.)
- Correspondence: ; Tel.:+972-8-9489761
| | - Ido Simon
- Plant Molecular Biology and Nano Biotechnology, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (I.S.); (O.S.)
| | - Shlomo Magdassi
- Casali Center of Applied Chemistry, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91905, Israel;
| | - Oded Shoseyov
- Plant Molecular Biology and Nano Biotechnology, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel; (I.S.); (O.S.)
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