Morpho Butterfly Wings Research Articles

Digital Holographic Interferometry for Micro-Deformation Analysis of Morpho Butterfly Wing

In this study, we present an analysis of deflections in a Morpho butterfly wing using digital holographic interferometry (DHI). Our methodology revolves around an off-axis lensless Fourier holographic setup, using laser excitation to induce deflections in the object. The implementation of a DHI setup, tailored for rapid monitoring of micro-deformation, is a central aspect of our research. We offer an overview of the theoretical foundations of this technique, complemented by both experimental and numerical results aimed at validating our findings. We designed an optical setup that enhanced both laser illumination and hologram reconstruction for the sample. The experimental findings decisively show that the proposed method is effective for rapid deformation analysis. The deformation of the wing can be measured with micro-meter accuracy thanks to numerical analysis.

Bubble-Guidance Breaking Gas Shield for Highly Efficient Overall Water Splitting.

Overall water splitting is a promising technology for sustainable hydrogen production, but the primary challenge is removing bubbles from the electrode surface quickly to increase hydrogen production. Inspired by the directional fluid transport properties of natural biological surfaces like Nepenthes peristome and Morpho butterfly's wings, here a strategy is demonstrated to achieve highly efficient overall water splitting by a bubble-guidance electrode, that is, an anisotropic groove-micro/nanostructured porous electrode (GMPE). Gradient groove micro/nanostructures on the GMPE serve as high-speed bubble transmission channels and exhibit superior bubble-guidance capabilities. The synergistic effect of the asymmetric Laplace pressure generated between microscale porous structure and groove patterns and the buoyancy along the groove patterns pushes the produced bubbles directionally to spread, transport, and detach from the electrode surface in time. Moreover, the low adhesive nanosheet arrays are beneficial to reduce bubble size and increase bubble release frequency, which cooperatively improve mass transfer with the microscale structure. Notably, GMPE outperforms planar-micro/nanostructured porous electrode (PMPE) in hydrogen/oxygen evolution reactions, with GMPE||GMPE showing better water splitting performance than commercially available RuO2||20 wt.% Pt/C. This work improves electrodes for better mass transfer and kinetics in electrochemical reactions at solid-liquid-gas interfaces, offering insight for designing and preparing gas-involved photoelectrochemical electrodes.

Bio-inspired dual-responsive photonic crystal with smart responsive hydrogel for pH and temperature detection

Responsive photonic crystals (PCs) with bio-inspired microstructures and tailorable functionalities are of critical importance for their potential applications in diverse fields such as biological detection, sensing, decoration, anti-counterfeiting, etc. However, limited by preparation technologies and design theories, it is still a challenge to accurately and uniformly deposit smart responsive materials on natural PC structures and achieve dual stimulus response. Herein, a simple and rapid in situ polymerization method is presented for preparing dual-responsive PCs with ultra-precise micro-/nanoscale hierarchical structures. Exposure of the reaction site by deacetylation of Morpho butterfly wings allows in situ polymerisation of poly (N-isopropylacrylamide-co-acrylic acid) (P(NIPAAM-co-AAc)) on the surface of the natural photonic structure. The obtained P(NIPAAM-co-AAc) photonic crystals (P(NIPAAM-co-AAc)-PCs) exhibited a dual response to pH and temperature reversibility. In addition, the synergistic effect of the structures and materials on the optical response of the natural PCs is revealed. This work allows the combination of natural hierarchical PC structures with smart hydrogel to achieve an optical response to pH and temperature, thus opening up the channels for responsive PC to multiple stimulus responses.

Investigating the Effect of Reflectance Tuning on Photocatalytic Dye Degradation with Biotemplated ZnO Photonic Nanoarchitectures Based on Morpho Butterfly Wings.

Photonic nanoarchitectures of butterfly wings can serve as biotemplates to prepare semiconductor thin films of ZnO by atomic layer deposition. The resulting biotemplated ZnO nanoarchitecture preserves the structural and optical properties of the natural system, while it will also have the features of the functional material. The ZnO-coated wings can be used directly in heterogeneous photocatalysis to decompose pollutants dissolved in water upon visible light illumination. We used the photonic nanoarchitectures of different Morpho butterflies with different structural colors as biotemplates and examined the dependence of decomposition rates of methyl orange and rhodamine B dyes on the structural color of the biotemplates and the thickness of the ZnO coating. Using methyl orange, we measured a ten-fold increase in photodegradation rate when the 20 nm ZnO-coated wings were compared to similarly coated glass substrates. Using rhodamine B, a saturating relationship was found between the degradation rate and the thickness of the deposited ZnO on butterfly wings. We concluded that the enhancement of the catalytic efficiency can be attributed to the slow light effect due to a spectral overlap between the ZnO-coated Morpho butterfly wings reflectance with the absorption band of dyes, thus the photocatalytic performance could be changed by the tuning of the structural color of the butterfly biotemplates. The photodegradation mechanism of the dyes was investigated by liquid chromatography-mass spectroscopy.

Development of ultra-thin radiation-shielding paper through nanofiber modeling of morpho butterfly wing structure

In medical institutions, radiation shielding is an effective strategy to protect medical personnel and patients from exposure. Reducing the weight of the shield worn by medical personnel in the radiation generating area plays a key role in improving their productivity and mobility. In this study, a new lightweight radiation shield was developed by electrospinning a polymer-tungsten composite material to produce nanofibers with a multi-layered thin-film structure similar to that of a morpho butterfly wing. The fabricated shield was in the form of 0.1 mm thick flexible shielding paper. The multi-layer structure of the thin shielding paper was obtained through nanofiber pattern formation via electrospinning a dispersion of tungsten particles. At 0.1 mm thickness, the paper’s shielding rate was 64.88% at 60 keV. Furthermore, at 0.3 mm thick and arranged in a laminated structure, the shielding rate was 90.10% and the lead equivalent was 0.296 mmPb. When used as an apron material, the weight can be reduced by 45% compared to existing lead products. In addition, the material is highly processable and can be used to manufacture various flexible products, such as hats, gloves, underwear, and scarves used in medical institutions.

Mimicking the structure of Morpho butterfly wing surface: a highly reflective nanostructure assembled by nanospheres

Inspired by the surface structure of Morpho butterfly wings, we theoretically propose a biomimetic nanosphere structure with high optical reflectivity. By adjusting the geometric parameters and material parameters of the nanostructure, we obtain reflectivity >99 % in a certain band; the high-reflection bandwidth depends on the period width, filling factor, and number of nanospheres. Its high-reflectivity bandwidth is less dependent on the incidental light angle compared with general single-layer or multilayer coatings for reflection enhancement. Unlike the biomimetic structures that are completely the same as the Morpho butterfly surface, this simplified structure can be assembled in ways other than photolithography and electron-beam lithography. We also analyzed several deviations of the structure, and the results show that our design allowed these deviations, which is helpful to achieving the effect of the structure in the preparation process. At the same time, the equivalent medium theory was used to analyze the nanostructure. The nanosphere structure has excellent potential applications in optical devices that require high reflectivity, such as laser resonant cavity and optical filters.

General morphological analysis of Orosi windows and morpho butterfly wing's principles for improving occupant's daylight performance through interactive kinetic façade

Daylight contains dynamic features such as color and intensity that may vary over time. The ideas of Orosi windows and biomimetic kinetic lessons of butterfly wings are viewed as essential tactics for regulating dynamic daylight. As a result, this research looks at a methodological technique for providing an appropriate combination of kinetic behavior and movement with colorful glass compositions to boost occupants' daylight performance. The research is being carried out using a multidisciplinary method that includes general morphological analysis (GMA) and a kinetic design strategy. The methodology uses GMA for parametric exploration between interconnected principles of Orosi windows and biomimetic lessons of Morpho butterfly wings to make a matrix of relationships between parameters. The kinetic façade changes the depth and scale of the hexagonal modular elements across a south direction in Iran. Moreover, the most optimal depth and scale of the hexagonal grid regarding the daylight performance metrics have been used to change the composition of colored glasses by periodic movements due to dynamic sun-timing and occupant's positions. The annual daylight metrics analysis of all kinetic alternatives represents high daylight performance by UDI, EUDI, sDA of 93.5, 6.29, and 78.37, respectively. The facade increases the amount of UDI up to 5.61 times regarding the base case while decreasing the amount of EUDI in the room by an average of 91.8%. Concerning predicting the risk of glare, as a point in time metric, the façade prevents visual discomfort by keeping most scenarios in the imperceptible range.

Photonic Crystals: A Review as Promising Tool for the Selective Detection of Toxic Gases

Photonic crystals (PhCs) based sensing nanotechnology has gained a lot of attention because of its unique structural and morphological characteristics. With the potential utility, these PhC materials are promising as sensitive, selective, economical, portable, and visually detectable gas/vapor sensors for environment quality monitoring. This review focuses on current progress in the natural and artificial PhCs for gas sensing. We will discuss different PhCs including morpho butterfly wings and their nanostructure mimics, porous silicon, Bragg stacks, and colloidal crystals. Moreover, their fabrication techniques for PhCs sensing materials, structural modifications, and sensing mechanisms will be analyzed. In this review article, we highlighted the problem and solution as emerging trends for recent advances in PhCs-based sensors and their applications in environmental monitoring and pollution control. Furthermore, this study envisions new methodologies for PhCs-based sensors that will be highly advanced and effective.

Conductive Nerve Guidance Conduits Based on Morpho Butterfly Wings for Peripheral Nerve Repair.

Peripheral nerve injury (PNI), causing loss of sensory and motor function, is a complex and challenging disease in the clinic due to the restricted regeneration capacity. Nerve guidance conduits (NGCs) have become a promising substitute for peripheral nerve regeneration, but their efficacy is often limited. Here, inspired by the physiological structures of peripheral nerves, we present a conductive topological scaffold for nerve repair by modifying Morpho butterfly wing with reduced graphene oxide (rGO) nanosheets and methacrylated gelatin (GelMA) hydrogel encapsulated brain-derived neurotrophic factor (BDNF). Benefiting from the biocompatibility of GelMA hydrogel, the conductivity of rGO and parallel nanoridge structures of wing scales, PC12 cells, and neural stem cells grown on the modified wing have an increased neurite length with guided cellular orientation. In addition, the NGCs are successfully obtained by manually rolling up the scaffolds and exhibited great performance in repairing 10 mm sciatic nerve defects in rats, and we believe that the NGCs can be applied in reparing longer nerve defects in the future by further optimization. We also demonstrate the feasibility of electrically conductive NGCs based on the rGO/BDNF/GelMA-integrated Morpho butterfly wing as functional nerve regeneration conduits, which may have potential value for application in repairing peripheral nerve injuries.

Effects of Measurement Configurations on the Sensitivity of Morpho Butterfly Scales Based Chemical Biosensor

The Morpho butterfly wing with tree-shaped alternating multilayer is an effective chemical biosensor to distinguish between ambient medium, and its detection sensitivity is inextricably linked to the measurement configuration including incident angle, azimuthal angle, and so on. In order to reveal the effects and the selection of measurement configuration. In this work, the model of the Morpho butterfly wing is built using the rigorous coupled-wave analysis method by considering its profile is a rectangular-groove grating. On basis of the above model, the reflectivity of different diffraction orders at a different incident angle and azimuthal angle is calculated, and the influence of incident angle and azimuthal angle on performance of Morpho butterfly scales-based biosensor is analyzed. The optimal incident angle at each azimuthal angle is given according to the proposed choice rule, then the azimuthal angle and the corresponding incident angle can be selected further.

Impedance mismatch-based enhancement of broadband reflectance of tungsten with bio-inspired multilayers

Optical coatings composed of thermomechanically superior materials with high reflectance in the broadband spectrum have recently attracted attention. Tungsten (W), among other VIB group materials, suits well for applications that require high thermomechanical stability but suffer from low reflectivity below 1 µm. This paper proposes a bio-inspired multilayer structure that lowers Tungsten's absorption over a broadband spectrum. The proposed design mimics the patterns observed on Morpho butterfly wings and reduces the absorption of W over a broad spectrum. At the initial stage, the impedance mismatch method is implemented to optimize the number and thickness of the homogeneous multilayers over the broadband spectrum. Then, the proposed pattern is incorporated into the homogenous structure. The effect of inhomogeneities on the transverse directions is investigated. The resulting spectral characteristics of both homogeneous and inhomogeneous structures are analyzed by wave impedance analysis. The total optical path was extracted with this analysis. Using this analysis, the mechanisms that trigger sharp reflection dips in homogenous layers are uncovered. S-parameters of the inhomogeneous structures are extracted and evaluated. Our findings indicate that the increased rate of change of the S-parameters phase in inhomogeneous structures is responsible for increased dips over the spectrum.

Biomimicry of Blue Morpho butterfly wings: An introduction to nanotechnology through an interdisciplinary science education module

AbstractBiomimicry is the practice of imitating naturally occurring bio‐designs through engineering and invention. For instance, Blue Morpho butterfly wing colors are a result of the reflection and refraction of nanostructures embedded in the wing and have inspired practical applications in nanofabrication and photonics. Interdisciplinary science educational materials have been developed that demonstrate the cross‐disciplinary aspects and biomimetic properties used in designing nano‐based devices. The unique optical properties of the Blue Morpho wing provides an excellent source of demonstrating how aspects of chemistry, biology, physics, and nanotechnology relate. Specifically, these educational tools demonstrate concepts including natural selection, chemical and physical properties, structure at the nanoscale, optical, and electromagnetic design. In addition, the engaging activities are correlated to how nanotechnology drives invention and provides students a mechanism to be introduced to the possibilities nanotechnology provides. A comprehensive combination of lab, cleanroom, and classroom activities are suggested to promote remote learning.

Light guidance in photonic structures of Morpho butterfly wing scales

In this paper, we investigate the impact of the periodicity along three orthogonal axes of the blue wing scales of Morpho butterflies, whereas most of the previous studies modeled the scale structure only considering one or two photonic crystal dimensions. Moreover, the previous optical studies of these scales focused on the light reflected by the wing, whereas we investigate the light propagation along the lamellae, this direction corresponding to the third dimension of the photonic crystal structure. Simulation results obtained using the finite-element method are compared with measurements and/or literature. These calculations, performed for different scale models and orientations, show that a significant part of the non-reflected light, essentially red and infrared, is guided by the lamellae towards the base of the scales where it can be more easily absorbed and the heat more quickly transferred to the hemolymph. This new phenomenon could contribute to the thermal balance of the insect and further illustrates the multifunctionality of the wings of Lepidoptera.

Evolutionary algorithms converge towards evolved biological photonic structures

Nature features a plethora of extraordinary photonic architectures that have been optimized through natural evolution in order to more efficiently reflect, absorb or scatter light. While numerical optimization is increasingly and successfully used in photonics, it has yet to replicate any of these complex naturally occurring structures. Using evolutionary algorithms inspired by natural evolution and performing particular optimizations (maximize reflection for a given wavelength, for a broad range of wavelength or maximize the scattering of light), we have retrieved the most stereotypical natural photonic structures. Whether those structures are Bragg mirrors, chirped dielectric mirrors or the gratings on top of Morpho butterfly wings, our results indicate how such regular structures might have spontaneously emerged in nature and to which precise optical or fabrication constraints they respond. Comparing algorithms show that recombination between individuals, inspired by sexual reproduction, confers a clear advantage that can be linked to the fact that photonic structures are fundamentally modular: each part of the structure has a role which can be understood almost independently from the rest. Such an in silico evolution also suggests original and elegant solutions to practical problems, as illustrated by the design of counter-intuitive anti-reflective coatings for solar cells.

In Vitro Bioactivity and Biocompatibility of Bio-Inspired Ti-6Al-4V Alloy Surfaces Modified by Combined Laser Micro/Nano Structuring.

The bioactivity and biocompatibility play key roles in the success of dental and orthopaedic implants. Although most commercial implant systems use various surface microstructures, the ideal multi-scale topographies capable of controlling osteointegration have not yielded conclusive results. Inspired by both the isotropic adhesion of the skin structures in tree frog toe pads and the anisotropic adhesion of the corrugated ridges on the scales of Morpho butterfly wings, composite micro/nano-structures, including the array of micro-hexagons and oriented nano-ripples on titanium alloy implants, were respectively fabricated by microsecond laser direct writing and femtosecond laser-induced periodic surface structures, to improve cell adherence, alignment and proliferation on implants. The main differences in both the bioactivity in simulated body fluid and the biocompatibility in osteoblastic cell MC3T3 proliferation were measured and analyzed among Ti-6Al-4V samples with smooth surface, micro-hexagons and composite micro/nano-structures, respectively. Of note, bioinspired micro/nano-structures displayed the best bioactivity and biocompatibility after in vitro experiments, and meanwhile, the nano-ripples were able to induce cellular alignment within the micro-hexagons. The reasons for these differences were found in the topographical cues. An innovative functionalization strategy of controlling the osteointegration on titanium alloy implants is proposed using the composite micro/nano-structures, which is meaningful in various regenerative medicine applications and implant fields.

Heat transfer properties of Morpho butterfly wings and the dependence of these properties on the wing surface structure.

The heat transfer properties of a material strongly rely on its surface structure. The wings of the Morpho butterfly have a unique surface structure with features of order and disorder. In this work, the surface temperature and radiative heat flux of Morpho butterfly wings with structural colour when a ceramic heater attached to the opposite surface of the wings was heated to 250 °C were evaluated in terms of their heat transfer properties. Morpho menelaus butterfly (MM) wings and Cithaerias (CE) wings with no periodic structure on their surface, were used as samples. The MM wings had higher surface temperature and radiative heat flux than the CE wings, which is the first report of heat transfer properties of the wings. The surface structure of the MM wings was changed by heat treatment in order to investigate the effect of the surface structural change on their heat transfer properties. The treatment changed the colour of the wings to red and brown, distorting the periodic structure. The radiative heat flux increased due to the change in the structure on their surface. XPS spectra revealed that the treatment leads to a slight change in the chemical structure of the wings. The spectral analyses results showed there was no obvious change in the mid-infrared absorbance. The heat radiative properties of the MM wings were strongly influenced by the surface structural changes due to the heat treatment.

Vapor detection through dynamic process of molecule desorption from butterfly wings

Abstract This work explores an alternative vapor sensing mechanism through analyzing dynamic desorption process from butterfly wings for the differentiation of both individual and mixed vapors quantitatively. Morpho butterfly wings have been used in differentiating individual vapors, but it is challenging to use them for the differentiation of mixed vapor quantitatively. This paper demonstrates the use of Morpho butterfly wings for the sensitive and selective detection of closely related vapors in mixtures. Principal components analysis (PCA) is used to process the reflectance spectra of the wing scales during dynamic desorption of different vapors. With the desorption-based detection mechanism, individual vapors with different concentrations and mixed vapors with different mixing ratios can be differentiated using the butterfly wing based sensors. Both the original butterfly wings and butterfly wings with surface modification show the capability in distinguishing vapors in mixtures, which may offer a guideline for further improving selectivity and sensitivity of bioinspired sensors.

Butterfly Wing Hears Sound: Acoustic Detection Using Biophotonic Nanostructure

The biophotonic nanostructures of Morpho butterfly wing display iridescent colors through the combined effect of light diffraction and interference. These nanostructures have attracted wide attention due to their high optical sensitivity and deformable material properties and have been applied to various infrared (IR), volatile organic compound (VOC), and pH sensors. This work explores the application of such biophotonic nanostructures of butterfly wing for acoustic detection and voice recognition. The pressure variation of the acoustic waves induces the vibration of butterfly wing diaphragm, resulting in the periodic change of reflectance. The integrated butterfly wing-based acoustic sensor shows high fidelity in replicating the original acoustic signals. The sensor also demonstrates promise in distinguishing human voices, which provides an alternative approach for voice recognition.

Cardiomyocytes-Actuated Morpho Butterfly Wings.

Morpho butterflies are famous for their wings' brilliant structural colors arising from periodic nanostructures, which show great potential value for fundamental research and practical applications. Here, a novel cellular mechanical visualizable biosensor formed by assembling engineered cardiac tissues on the Morpho butterfly wings is presented. The assembled cardiomyocytes benefit from the periodic parallel nanoridges of the wings and can recover their autonomic beating ability with guided cellular orientation and good contraction performance. As the beating processes are accompanied by the cardiomyocytes' elongation and contraction, the elastic butterfly wing substrate undergoes the same cycle of deformations, which causes corresponding synchronous shifts in their structural colors and photonic bandgaps for self-reporting of the cell mechanics. It is demonstrated that this self-reporting performance can be further improved by adding oriented carbon nanotubes in the nanoridges of the wings for the culture. In addition, taking advantage of the similar size of the cardiomyocyte and a single Morpho wing scale, the investigation of single-cell-level mechanics can be realized by detecting the optical performance of a single scale. These remarkable properties make these butterfly wings ideal platforms for biomedical research.

Phototunable Morpho Butterfly Microstructures Modified by Liquid Crystal Polymers

AbstractThe unique hierarchical microstructures of the Morpho butterfly wing (MBW) exhibit angle independent blue iridescence. Biomimicking these microstructures and turning them into functional photonic crystals (PhCs) have fascinated scientists yet remain challenging. Here, a phototunable PhC is fabricated by depositing the azobenzene‐containing linear liquid crystal polymer (LLCP) onto the MBW template. Thanks to the excellent mechanical properties and deformability of LLCP, the generated 3D bilayer microstructures demonstrate hierarchical deformation upon UV light irradiation, leading to a blueshift of the reflection peak (70 nm) and a remarkable change of reflectance (40%). This phototunable PhC may have potential applications in pigments, cosmetics, and sensors.