High-performance Metamaterials Research Articles

Ultra-soft cellular solids inspired by marine mussel plaques: scaling of the mechanical properties

The porous core of the marine mussel provides mechanical advantages of achieving substantial deformation and high toughness. Inspired by the unique mechanical behaviours of mussel plaque cores, the present study develops ultra-soft, stretchable and tough cellular solids by bio-mimicking their porosity and properties. Although scaling laws to correlate the mechanical properties of cellular solids with bulk materials have been established, they are primarily based on experimental data from stiff cellular solids. In this article, the scaling law for soft cellular solids is studied to relate tensile properties and toughness with volume fractions. Unlike conventional stiff cellular solids, the scaling law shows that soft lattices experience bending-dominated deformation at the elastic state and fail under stretching-dominated deformation. Uniaxial and planar tensile tests demonstrate that the proposed soft lattices achieved Young’s modulus of 0.04 ∼ 0.17 MPa, failure strain of 135.5 ∼ 213.9 % and toughness of 582 ∼ 941 J m −2 by manipulating the volume fraction ( 0.2 ∼ 0.5 ), positioning them as softer, more stretchable and tougher than the majority of engineering foams in the Ashby diagram. In addition, the toughness of soft lattices is found to be sensitive to volume fraction but insensitive to initial crack length, thickness and height ( ≥ 20 m m ). Two distinct failure modes, truss failure and joint failure, are correlated with volume fraction. The soft lattice with a volume fraction (around 0.4) similar to mussel plaque fails at the transition of these two failure modes and achieves the highest toughness. This study contributes new insights to the materials science community and lays the foundation for the development of lightweight, damage-tolerant and high-performance metamaterials.

An isogeometric analysis of solar panels with a bio-inspired substrate

We in this paper propose a high-performance design using bio-inspired metamaterials for multilayered perovskite solar cell (MPSC) plates. The static bending and free vibrational responses of the newly designed MPSC panels with the presence of the triply periodic minimal surface (TPMS) substrate are subsequently investigated numerically. The displacements of the present plate model are then approximated by five-variable higher-order shear deformation theories (HSDTs). The weak forms are established for both the static bending and free vibration problems and subsequently derive the discrete forms using the NURBS-based isogeometric approach. To enhance the operational efficiency of solar panels in challenging environments, we integrate advanced lightweight architectures based on bio-inspired TPMS structures as a substrate layer into the original solar panel design. In this research, three widely employed TPMS structures: Primitive, Gyroid, and I-graph and Wrapped Package-graph (IWP), are examined in conjunction with two functional grading patterns implemented through the thickness direction. For the first time, the static bending performance of MPSC plates integrated into a TPMS-based substrate layer and subjected to wind pressure as well as thermal conditions is comprehensively studied. In addition, the influence of several significant factors on the free vibration behavior of MPSC plates is also elucidated. The findings show a promising and intriguing design avenue, particularly in the application of high-performance metamaterials to address contemporary challenges in renewable energy usage and environmental protection.

A theoretical framework for joining multiple locally resonant bandgaps of metamaterials towards a super-wide bandgap

In this paper, we establish a theoretical framework for joining multiple locally resonant bandgaps of composites that consist of a continuous matrix and discrete particles towards a super-wide bandgap through the damping effect of the inclusions or interphases. The binary locally resonant material is taken as an example. The analytical expressions of its first bandgap, effective mass and transmission characteristics are obtained by virtue of the equivalent discrete models. The theoretical framework and the optimized results are validated by numerical examples and experiments. Then, the theoretical framework is further used to design composite metamaterials that have the merits of small characteristic size, light weight, high static stiffness, and low-frequency bandgaps simultaneously which are characterized by a dimensionless comprehensive performance index. The results demonstrate that the generalized bandwidth can be increased by four folds, and the comprehensive performance index can be doubled through optimization. The methods developed in this work are applicable to other kinds of locally resonant metamaterials, and can be used to guide the design of high-performance metamaterials.

Numerical study of an ultra-broadband, wide-angle, polarization-insensitive absorber in visible and infrared region

An ultra broadband high-performance metamaterials absorber is designed based on the Fabry-Perot resonance effect and hybrid coupling theory. In this paper, we use the numerical method to analyze the absorption characteristics of the absorber under the conditions of wide band, different polarization states and large angle oblique incidence. The results reveal that the absorption band of the absorber is 300 nm–3000 nm, and its average absorption rate exceeds 93%. In addition, the absorptivity of the absorber is less affected by the polarization angle and incident angle of the incident light. The physical mechanism of wide-band high-absorption is analyzed, which is mainly caused by Fabry-Perot resonance, surface plasmon resonance, local surface plasmon resonance and the hybrid coupling among them. The proposed metamaterial absorber is expected to play a role in invisible devices, solar cells and other fields owing to its wide absorption bandwidth, high absorption, independent to polarization and stable at wide-angle of incidence.

Epitaxial Assembly of Nanoparticles in a Diblock Copolymer Matrix: Precise Organization of Individual Nanoparticles into Regular Arrays

Precise organization of nanoparticles (NPs) into regularly well-defined arrays represents a continuing challenge in the development of high-performance metamaterials. Herein, zone-annealed diblock ...

Machine learning in additive manufacturing: State-of-the-art and perspectives

Additive manufacturing (AM) has emerged as a disruptive digital manufacturing technology. However, its broad adoption in industry is still hindered by high entry barriers of design for additive manufacturing (DfAM), limited materials library, various processing defects, and inconsistent product quality. In recent years, machine learning (ML) has gained increasing attention in AM due to its unprecedented performance in data tasks such as classification, regression and clustering. This article provides a comprehensive review on the state-of-the-art of ML applications in a variety of AM domains. In the DfAM, ML can be leveraged to output new high-performance metamaterials and optimized topological designs. In AM processing, contemporary ML algorithms can help to optimize process parameters, and conduct examination of powder spreading and in-process defect monitoring. On the production of AM, ML is able to assist practitioners in pre-manufacturing planning, and product quality assessment and control. Moreover, there has been an increasing concern about data security in AM as data breaches could occur with the aid of ML techniques. Lastly, it concludes with a section summarizing the main findings from the literature and providing perspectives on some selected interesting applications of ML in research and development of AM.

Controlled Assembly of Inorganic Nanosheets and Its Application to High-Performance Metamaterials

Controlled Assembly of Inorganic Nanosheets and Its Application to High-Performance Metamaterials

Equivalent energy level hybridization approach for high-performance metamaterials design

Metamaterials have microscopic physical properties highly analogous to real materials, since their characteristic frequencies behave as equivalent energy levels, providing an efficient route to deal with stacked meta-atoms with strong interactions. Based on the hybridization of equivalent energy levels theory, in this paper, we designed transmissive multilayer metasurfaces to convert the handedness of a circularly polarized wave with high efficiency in a broad bandwidth. In stacked metasurfaces, the equivalent energy levels gradually split with an increasing layer number (i.e. meta-atoms). Their hybridization introduces trapped modes with near-unity transmission, contributes to a near-π transmission phase difference and promotes the split modes overlapping to form a broad bandwidth. Through theoretical calculations, numerical simulations and experimental measurements, a four-layer metasurface was shown to exhibit a high transmission conversion coefficient (80–98%) of a circularly polarized wave covering the whole X-band. Furthermore, a multifunctional meta-lens with broad bandwidth was designed and fabricated based on the Pancharatnam-Berry phase to converge or diverge incident Gaussian beams with different handedness at a high efficiency rate.

Photonics and plasmonics go viral: self-assembly of hierarchical metamaterials.

Sizing and shaping of mesoscale architectures with nanoscale features is a key opportunity to produce the next generation of higher-performing products and at the same time unveil completely new phenomena. This review article discusses recent advances in the design of novel photonic and plasmonic structures using a biology-inspired design. The proteinaceous capsids from viruses have long been discovered as platform technologies enabling unique applications in nanotechnology, materials, bioengineering, and medicine. In the context of materials applications, the highly organized structures formed by viral capsid proteins provide a 3D scaffold for the precise placement of plasmon and gain materials. Based on their highly symmetrical structures, virus-based nanoparticles have a high propensity to self-assemble into higher-order crystalline structures, yielding hierarchical hybrid materials. Recent advances in the field have led to the development of virus-based light harvesting systems, plasmonic structures for application in high-performance metamaterials, binary nanoparticle lattices, and liquid crystalline arrays for sensing or display technologies. There is still much that could be explored in this area, and we foresee that this is only the beginning of great technological advances in virus-based materials for plasmonics and photonics applications.

Electromagnetic characteristics of Hilbert curve-based metamaterials

As the typical building blocks of metamaterials, the cut wire and the split ring resonator have been extensively studied in recent years. Besides them, the space-filling curve-based metamaterials are receiving great attentions because of their intrinsic subwavelength and multi-bands characteristics. In this work, we have investigated experimentally and numerically the electromagnetic characteristics of such Hilbert curve metamaterial in the microwave frequency regime and found a deeply subwavelength magnetic resonance supported by the fractal pattern and featuring the wavelength-to-size ratio more than 20. The subwavelength electromagnetic properties of the Hilbert curve will be beneficial to realize high-performance metamaterials.