Architectural Materials Research Articles

Recent Progress in Conjugated Polymers-Based Donor–Acceptor Semiconductor Materials for Photocatalytic Hydrogen Evolution from Water Splitting

Exploration of high-efficiency stabilization and abundant source-conjugated polymers semiconductor materials with suitable molecular orbital energy levels has always been a hot topic in the field of photocatalytic hydrogen evolution (PHE) from water splitting. In the recent years, constructing the intramolecular donor–acceptor (D–A)-conjugated architecture copolymers has been proved as one of the most excellent photocatalyst modification tactics for optimizing the PHE properties because of unique advantages, including easy regulate band-gap position, fast transfer charge carrier in the intramolecular architecture, superior sunlight absorption capacity and range, large interfacial areas, and so forth. Therefore, in this minireview, we summarize the latest research progress of D–A architecture semiconductor materials for PHE from water splitting. First, we briefly overview the fundamental description and principles for the construction D–A heterostructures in the photocatalytic system. After that, the application of D–A architecture photocatalyst for PHE reaction over different classes of organic semiconductors have been discussed in detail. At last, the present development prospects and future potential challenges of D–A architecture materials are proposed. We hope this minireview has some parameter values for the further developments of intermolecular special structured organic semiconductor material in the future PHE research.

Mechanical coupling and tuned anisotropic elasticity: Numerical and experimental material design for shear-normal and shear-shear interactions

Mechanical coupling in architectured materials has been traditionally investigated in the context of generalized continuum mechanics and is often assumed to be non-existent in the framework of classical continuum mechanics. In this paper, we challenge this misconception and study an anisotropic architectured material exhibiting shear-shear and shear-normal coupling from the standpoint of classical continuum mechanics. The material is non-regular tetrahedron lattice, a potential candidate for biomedical implants, but the lack of understanding about its anisotropic behavior and mechanical couplings has limited its application. We exploited the unit-cell definition with periodic boundary conditions and performed elastic and elastoplastic homogenizations. Non-zero coupling sub-matrices appeared in the homogenized elasticity matrix, which we further transformed into material’s natural coordinate system using elastic distance function. This allowed for anisotropy identification and determination of all the coupling parameters. Next, compression tests are conducted on laser powder bed fused Al-12Si (mass%) lattice samples with different relative densities and spatial orientations. Employing test data, mechanical anisotropy and shear-normal couplings are experimentally characterized. Both numerical and experimental results confirmed the presence of mechanical couplings and predicted a similar anisotropic tendency in the material. Finally, the role of manufacturing defects in deterioration of as-designed mechanical properties is discussed.

Investigation of the change in wettability properties and corrosion behavior of AISI 304 after laser surface texturing

Stainless steel is a widely used material in industry, architecture, and medical instruments. However, after various thermal processing of stainless steels, chromium carbides can be formed, which locally depletes the chromium available to form a passive film and reduces the corrosion performance. Laser surface treatment can change the surface chemistry of the steel and improve some electrochemical characteristics. However, these characteristics are influenced by the laser power, pulse width, distance between the lines, scanning speed, etc., which all change the surface chemistry and characteristics of laser surface texturing. Simultaneously, the ability to repel liquids that cause corrosion actions could combine to enhance corrosion performance. Since the wettability of a solid surface depends both on its topography and chemical nature, the micro structuring of an austenitic steel surface is an effective way of fabricating hydrophobic or super hydrophobic corrosion-resistant surfaces. For this reason, this study discusses the effect of laser power in the impact zone and the distance between raster lines on the microstructure, wettability, and corrosion resistance of austenitic steel (AISI 304) when exposed to nanosecond fiber laser radiation. The results indicate that parameter-controlled micro structuring can be used to form both hydrophilic and hydrophobic surfaces with different electrochemical performances.

Metal additive manufacturing of alloy structures in architecture: A review on achievements and challenges

There is a growing trend in modern architecture towards asymmetrical building layouts. This development can be attributed to the proliferation of cutting-edge production methods and structurally novel approaches. With the advent of computational design and digital manufacturing techniques, formerly static designs may now be modified to create one-of-a-kind, high-performance prototypes. Metal additive manufacturing (MAM) is a cutting-edge production method that paves the way for new architectural designs, construction processes, and materials. Interesting possibilities for optimising structural elements are made possible by MAM because of its ability to deposit material just where it is structurally necessary. The construction sector places a premium on directed energy deposition additive manufacturing (DED AM) and wire arc additive manufacturing (WAAM). The adaptability of these two technologies in the construction industry and their possible future applications are explored in this literature review.

In situ investigations of failure mechanisms of silica fibers from the venus flower basket (Euplectella Aspergillum).

The fibers of the deep-sea sponge Euplectella aspergillum exhibit exceptional mechanical properties due to their unique layered structure at a micrometer length scale. In the present study, we utilize a correlative approach comprising of in situ tensile testing inside a scanning electron microscope (SEM) and post-failure fractography to precisely understand mechanisms through which layered architecture of fibers fracture and improves damage tolerance in tensile loading condition. The real-time observation of fibers in the present study confirms for the first time that the failure starts from the surface of fibers and proceeds to the center through successive layers. The concentric layers surrounding the central core sacrifice themselves and protect the central core through various toughening mechanisms like crack deflection, crack arrest, interface debonding, and fiber pullout. STATEMENT OF SIGNIFICANCE: Biological materials often exhibit multiscale hierarchical structures that can be incorporated into the design of next generation of engineering materials. The fibers of deep-sea sponge E. aspergillum possess core-shell like layered architecture. Our in situ study reveals astounding strategies by which this architecture delays the fracture of the fiber. The core-shell architecture of these fibers behaves like fiber-reinforced ceramic matrix composite, where the outer shells act as a matrix and the central core acts as a fiber. The outer shells take the environmental brunt and scarify themselves to protect the central core. The precise understanding of damage evolution presented here will help to design architected materials for load-bearing applications.

Silver nanowire electrodes for transparent light emitting devices based on WS2 monolayers

Transition metal dichalcogenide (TMDC) monolayers with their direct band gap in the visible to near-infrared spectral range have emerged over the past years as highly promising semiconducting materials for optoelectronic applications. Progress in scalable fabrication methods for TMDCs like metal-organic chemical vapor deposition (MOCVD) and the ambition to exploit specific material properties, such as mechanical flexibility or high transparency, highlight the importance of suitable device concepts and processing techniques. In this work, we make use of the high transparency of TMDC monolayers to fabricate transparent light-emitting devices (LEDs). MOCVD-grown WS2 is embedded as the active material in a scalable vertical device architecture and combined with a silver nanowire (AgNW) network as a transparent top electrode. The AgNW network was deposited onto the device by a spin-coating process, providing contacts with a sheet resistance below 10 Ω sq−1 and a transmittance of nearly 80%. As an electron transport layer we employed a continuous 40 nm thick zinc oxide (ZnO) layer, which was grown by atmospheric pressure spatial atomic layer deposition (AP-SALD), a precise tool for scalable deposition of oxides with defined thickness. With this, LEDs with an average transmittance over 60% in the visible spectral range, emissive areas of several mm2 and a turn-on voltage of around 3 V are obtained.

Experimental and numerical analysis of shear bonding behavior of interface between stone and ultra-high performance concrete made with POM fiber

Ultra-high performance concrete (UHPC) is a promising civil engineering cementitious material characterized by superior mechanical properties, where the compressive strength and elastic modulus are comparable to stone, therefore, UHPC is an ideal potential rehabilitation material for stone architecture. The excellent interfacial bonding property is the premise of UHPC reinforced existing stone structure. In this study, the bonding behavior of interface between stone and UHPC made with polyoxymethylene (POM) fiber was investigated by push-off tests, and the influence of stone surface treatment on shearing performance was analyzed by experiment and numerical simulation. The results showed that the interfacial shearing behavior of composites is associated with the interface roughness, especially the groove treatment, altering the failure mode and improving the shear strength as well as ductility, which is due to the interlocking mechanism and the distribution of fibers in groove. The suitable groove depth is recommended as 20 mm in the UHPC-stone composites using POM fiber with a length of 8 mm. The load–strain relationships of UHPC and stone are similar in the elastic stage due to the comparable elastic modulus, while present nonlinear characteristic in the plastic stage. The numerical simulation with a bilinear stress-displacement model can effectively predict the interfacial bonding behavior of UHPC-stone composites, and analyze the slippage distribution along with the interface. By means of stress contour, it is found that the shearing stress is mainly distributed non-uniformly around the interface, and the stress concentration location is consistent with the experimental failure region. Through the parametric study, it is revealed that the interface shear capacity of UHPC-stone is affected by the groove shapes and depths.

Thieno[3,2-b]thiophene and triphenylamine-based hole transport materials for perovskite solar cells

Heterocyclic compounds have played significant roles in achieving high performance as hole transport materials (HTMs) for perovskite solar cell (PSC) applications. Various studies have focused on the development of fused heterocyclic conjugated structures for hole transport materials. In this report, three novel π-extended conjugated materials (M1-M3), based on thieno[3,2-b]thiophene (TT) and 4,4′-dimethoxytriphenylamine [TPA(OMe)2], were designed and successfully synthesized via Palladium (0) catalyzed Suzuki coupling reaction. Their optical, electrochemical, and thermal properties were investigated by UV-Vis, fluorescence, cyclic voltammetry, and thermal analysis. The materials were utilized as hole transport materials in p-i-n architecture perovskite solar cells, which displayed performances of open-circuit voltage (Voc) as high as 1,050 mV, a maximum short-circuit current (Jsc) of 16,9 mA/cm2, a maximum fill factor (FF) of 29.3%, and a power conversion efficiency (PCE) of 5.20%. This work demonstrated that thieno[3,2-b]thiophene and TPA(OMe)2-based structures are promising cores for high-performance hole transport materials in perovskite solar cell architecture.

Generalized yield surface for sheet-based triply periodic minimal surface lattices

Triply periodic minimal surfaces (TPMS), which are a class of architected cellular materials, have attracted significant attention lately, due to their prevailing mechanical, electrical and chemical properties, to name a few, and due to the advancements in additive manufacturing technologies that make it possible to print such materials. However, simulating the elastic-plastic mechanical behavior of structural systems (e.g., beams, plates, cores of sandwich panels, structural systems with various levels of geometric complexity) that are latticed with thousands of TPMS lattices are computationally expensive to model explicitly, and hence the need to develop accurate yield surfaces in order to capture their plastic behavior in a homogenized approach. In this work, a generalized initial yield criterion is proposed for sheet-based TPMS lattices, which incorporates the Lode parameter L. The initial yielding of five different sheet-based TPMS lattices are investigated in five different loading conditions. These lattices are Schoen's I-WP (IWP-s), Gyroid (GYR-s), Diamond (DIA-s), F-RD (FRD-s) and Primitive (PRIM-s). The proposed yield criterion accurately predicts the initial yielding of all these lattices in all the loading conditions considered, outperforming other yield criteria currently proposed in literature.

Recellularized lymph node scaffolds with human adipose-derived stem cells enhance lymph node regeneration to improve lymphedema

To overcome the limitations of lymphedema treatment, human adipose-derived stem cells (hADSCs) were injected into decellularized lymph nodes to produce a recellularized lymph node-scaffold, and the effect of lymphangiogenesis was investigated in lymphedema animal models. Axillary lymph nodes were harvested from Sprague Dawley rats (7 weeks old, 220–250 g) for decellularization. The decellularized lymph nodes were performed and PKH26-labeled hADSCs (1 × 106/50 µL) were injected in the decellularized lymph node-scaffolds. Forty rats were equally divided into four groups: lymphedema as control group, hADSC group, decellularized lymph node-scaffold group, and recellularized lymph node-scaffold group. The lymphedema model was made by removing inguinal lymph nodes, and hADSCs or scaffolds were transplanted. Histopathological assessments were performed by hematoxylin and eosin and Masson’s trichrome staining. Lymphangiogenesis was evaluated by Immunofluorescence staining and western blot. Decellularized lymph nodes showed virtually complete absence of cellular material and maintenance of lymph node architecture. The hADSCs were significantly observed in recellularized lymph node-scaffolds group. The recellularized lymph node-scaffold group was histologically similar to normal lymph nodes. The vascular endothelial growth factor A and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) in immunofluorescence staining were highly expressed in recellularized lymph node-scaffolds group. Also, the expression of LYVE-1 protein significantly increased in recellularized lymph node-scaffold group compared with others. Recellularized lymph node -scaffold had a much better therapeutic effect than stem cells or decellularized lymph node-scaffold alone, and induced stable lymphangiogenesis.

Pre-evaluation and visual simulation of energy consumption influencing factors of smart and healthy architecture in the design stage

This research aims to carry out energy simulation of various setting factors of office space in smart and healthy architecture in the design stage. First, we established an office model based on Japanese architecture energy efficiency standards; then, we simulated the energy consumption process by setting reasonable factor parameters by utilising Openstudio; finally, the main factors contribute to energy consumption level of the office space and its energy saving potential were explored. Taking Hokkaido, Japan, as an example, by simulating the three major factors of smart and healthy architecture: smart devices, architecture materials, and human behaviour schedule, the effect of energy saving is calculated in the architectural design stage.

Single-shot forward and inverse hierarchical architected materials design for nonlinear mechanical properties using an Attention-Diffusion model

Inspired by natural materials, hierarchical architected materials can achieve enhanced properties including achieving tailored mechanical responses. However, the design space for such materials is often exceedingly large, and both predicting mechanical properties of complex hierarchically organized materials and designing such materials for specific target properties can be extremely difficult. In this paper we report a deep learning approach using an attention-based diffusion model, capable of providing both, forward predictions of nonlinear mechanical properties as a function of the hierarchical material structure as well as solving inverse design problems in order to discover hierarchical microstructure candidates for a specified nonlinear mechanical response. We exemplify the method for a system of compressively loaded four-hierarchy level materials derived from a family of honeycomb structures, where patterns of distributed buckling events are unitary deformation events that control small- and large-scale deformation behavior. Our model offers exquisite single-shot end-to-end performance in both forward and inverse directions across the entire range of deformation regime, and is capable of rapidly discovering multiple solutions that satisfy a design objective in accordance with the known physical behavior elucidated by, and validated with, coarse-grained simulations. The model provides an effective way towards biologically inspired materials design for high-throughput discovery in order to achieve diverse nonlinear constitutive relationships.

Preparation and photochromic behavior of borosilicate aluminate glass for smart window and curtain wall applications

Sunlight-induced photochromic glass exhibits attractive application prospects in the field of architecture materials. In this work, a series of borosilicate aluminate photochromic glasses containing AgCl nanocrystals were prepared. The photochromic property and mechanisms were systematically investigated. The color of the glass turned from transparent to black (or dark grey) under the irradiation of 365 nm ultraviolet light (or sunlight). Placing in a dark environment, the color of photochromic glass gradually restores to its initial state. From the results of in situ TEM and XPS measurement, it is found that the photochromic and self-bleaching behavior of borosilicate aluminate glass originated from the formation and decomposition of silver nanoparticles. Utilizing the photochromic and self-bleaching properties of the glass, the transmittance of the glass could be reversibly modulated. The cycle measurement shows excellent repeatability, demonstrating the potential application of AgCl-contained borosilicate aluminate photochromic glass in the fields of smart building windows and curtain walls.

Relationship between topological structures and mechanical properties of artificially architected SiC cellular ceramics: Experimental and numerical study

Due to their topological superiority, the architected materials facilitate the improvement of the physical and mechanical properties of cellular materials. With the progress of additive manufacturing technologies, the fabrication of architected silicon carbide (SiC) cellular ceramics has become achievable. This study focuses on the indirect additive manufacturing method of SiC cellular ceramics consisting of 3D printing, replication, and reaction-bonded sintering. To study the impact of the topology on the mechanical performance, three strut-based unit cell structures and stochastic foam with robust solid struts were experimentally and numerically studied. Results showed that the hexahedron structure has the highest compression strength, the tetrakaidecahedron structure has the highest flexural strength, while the regular structures have higher mechanical performance than the stochastic foam. The deformation mechanisms of the topologies under the compression load indicated that the hexahedron, tetrakaidecahedron, and stochastic foam favor the bending-dominated deformation mode, while the octet favors the stretching-dominated deformation mode.

HOW METAVERSE EVOLVES THE ARCHITECTURAL DESIGN

Architects have long relied on visualization tools to develop their concepts for specific design problems. From the early traditional drawings to the three-dimensional visualizations and virtual environments, all have enabled architects to demonstrate design outputs relatively early in the process. Real-world projects are similar to what architects imagined from the beginning. In other words, the design process has always started by creating the digital representation of a project and then attempting to replicate it in real life. Once the digital representation of design parts is complete, architects prepare their design for construction. However, the final visualization emerges from actual architectural functions, structure constraints, Gravity, materiality, privacy, and physical laws, meaning that architecture evolves the digitally represented visualizations. With the growth of the metaverse, all physical restrictions are being eliminated, and architects can expand the boundaries of how spaces can be represented regardless of being virtual or physical. As a virtual environment on the internet, the metaverse redefines the rules of architecture and offers endless possibilities for architectural innovation. This article aims to explore the role the metaverse plays in designing architecture. It outlines the fundamental concepts of the metaverse to identify significant elements that could influence architecture design.

Development of biodegradable customized tibial scaffold with advanced architected materials utilizing additive manufacturing

In the last decade, the development of customized biodegradable scaffolds and implants has attracted increased scientific interest due to the fact that additive manufacturing technologies allow for the rapid production of implants with high geometric complexity constructed via commercial biodegradable polymers. In this study, innovative designs of tibial scaffold in form of bone-brick configuration were developed to fill the bone gap utilizing advanced architected materials and bio-inspired diffusion canals. The architected materials and canals provide high porosity, as well as a high surface area to volume ratio in the scaffold facilitating that way in the tissue regeneration process and in withstanding the applied external loads. The cellular structures applied in this work were the Schwarz Diamond (SD) and a hybrid SD&FCC hybrid cellular material, which is a completely new architected material that derived from the combination of SD and Face Centered Cubic (FCC) structures. These designs were additively manufactured utilizing two biodegradable materials namely Polylactic acid (PLA) and Polycaprolactone (PCL), using the Fused Filament Fabrication (FFF) technique, in order to avoid the surgery, for the scaffold's removal after the bone regeneration. Furthermore, the additively manufactured scaffolds were examined in terms of compatibility and assembly with the bone's physical model, as well as, in terms of mechanical behavior under realistic static loads. In addition, non-linear finite element models (FEMs) were developed based on the experimental data to accurately simulate the mechanical response of the examined scaffolds. The Finite Element Analysis (FEA) results were compared with the experimental response and afterwards the stress concentration regions were observed and identified. Τhe proposed design of scaffold with SD&FCC lattice structure made of PLA material with a relative density of 20% revealed the best overall performance, showing that it is the most suitable candidate for further investigation (in-vivo test, clinical trials, etc.) and commercialization.

Wear characteristics, reduction techniques and its application in automotive parts – A review

Wear phenomenon impact the operating efficiency and service life of engineering materials due to the influence of surface interaction at different working conditions. Successive tribological studies on wear-resistant materials in the last decade is estimated at approximately 40% of friction and wear, including laboratory tests. Most locally improvised wear testers in accordance with American Society for Testing and Materials (ASTM) and European (EN) standards, though, achieve 95–97% parametric accuracies with reduced cost, they hardly harmonize degradation and Archards coefficients for all possible wear factors, providing little data for simulation of mechanical and chemical wears which are responsible for non-uniform aggregation of wear patterns in practice. Complexities of intermeshing factors which combine to influence the effectiveness of developed test devices span over loads, speeds, temperatures, pressures, and ambience for various applications. This study highlights the techniques of wear characterization, test standards, and wear reduction with emphasis on surface texturing for improved eta/beta phase re-arrangements at low working temperatures in the enhancement of grain contraction during high bias-voltage cathodic substrate multi-phase coating, phosphating during pretreatments using peening techniques, residual stress reduction during cryogenic heat treatments as well as the impact of suitable architectural matrix composite strengthening, microstructures, and material reinforcements as suitable factors to influence improved tribological behaviors in materials. Optimal additive manufacturing (AM‐fabricating) techniques with pretreatments, thermal cycling, and tempering can engineer enhanced anti-tribocorrosion in automotive components.

Emergence of elastostatic strain-gradient effects from topological optimization

There are very few examples of architectured materials producing significant strain-gradient effects in elastostatics. In the present paper, we generate for the first time new microstructures featuring these effects from topological optimization of two-dimensional periodic media. The optimized shape functionals depend on the first and second-order homogenized tensors, obtained from a two-scale asymptotic expansion homogenization scheme. The optimization method applied here relies on the recently rigorously derived topological derivative of the second-order homogenized tensor, measuring the strain-gradient sensitivity with respect to a small circular inclusion at the microscopic level endowed with different material property from the background. This previous theoretical work allows an accurate numerical implementation.

Engineered living materials for sustainable and resilient architecture

Engineered living materials for sustainable and resilient architecture

Use of Waste Building Materials in Architecture and Urban Planning—A Review of Selected Examples

Modern environmental protection standards have a direct impact on the construction and shaping of public space. Designers are increasingly reaching for materials produced via recycling technologies. Waste materials are more readily adopted and used in urban planning and architecture. Current projects in this area are being increasingly designed to meet the requirements of the circular economy, which is facilitated by the reuse of once-used components. The aim of the study is to review research papers in the Scopus database (bibliometric analysis) and other selected materials applied in construction, which are recycled and used again in various ways in the construction of subsequent buildings. The results show various application possibilities of recycled materials in construction. The study draws attention to the fact that the use of recycled materials in modern construction is becoming more and more effective, which may contribute to increasing the share of the circular economy in the implementation process related to this subject.