Characterization Of Materials Research Articles

3D microstructure reconstruction and characterization of porous materials using a cross-sectional SEM image and deep learning

Accurate assessment of the three-dimensional (3D) pore characteristics within porous materials and devices holds significant importance. Compared to high-cost experimental approaches, this study introduces an alternative method: utilizing a generative adversarial network (GAN) to reconstruct a 3D pore microstructure. Unlike some existing GAN models that require 3D images as training data, the proposed model only requires a single cross-sectional image for 3D reconstruction. Using porous ceramic electrode materials as a case study, a comparison between the GAN-generated microstructures and those reconstructed through focused ion beam-scanning electron microscopy (FIB-SEM) reveals promising consistency. The GAN-based reconstruction technique demonstrates its effectiveness by successfully characterizing pore attributes in porous ceramics, with measurements of porosity, pore size, and tortuosity factor exhibiting notable agreement with the results obtained from mercury intrusion porosimetry.

Preparation and Characterization of Anti-Microbial Wound Healing Materials from Natural Origins

Abstract Many types of polymers utilized as wound dressings, Polycaprolactone (PCL) displays high degree of biocompatibility as well as biodegradability, the mechanical strength states PCL in the foreground materials used in wound healing therapies. Current work aims to develop new types of wound plaster dressing, a multiple of natural and medical materials (aloe Vera, calendula and phenobarbital) were used to enhance the anti-microbial behavior as well as pain removal during wound healing period. Aloe Vera gels, Calendula extraction, with phenobarbital drug were precipitates on PCL layer in different percentage. Microstructure observation proves that polycaprolactone polymer is good base material supports dressing constituents, wound dressing homogeneity increased due to chemical reactions between the Aloe Vera and other materials. the main elements of dressing (carbon and oxygen) observed from chemical analysis (EDS) which is also showed that using combination of natural plants (aloe vera and Calendula) with phenobarbital medicine create wound plaster layer with wide range of active elements lead to therapeutic effects including antibacterial, In (FTIR) the results show using mixture of natural additives (aloe, calendula), medicine like phenobarbital in PCL lead to create wound plaster with high (OH) content acts to expedite the skin’s healing process by maintaining the natural level of minerals and hydration at wound area. Hydrophobicity of wound can minimized when adding some hydrophilic materials like Aloe Vera, phenobarbital and calendula, Aloe Vera gel, phenobarbital, as well as calendula decrease the contact angle value. Providing high adhesion between wound plaster and skin tissue. All prepared wound plaster has same and high resistance to Staphylococcus bacteria (40mm).

Electrochemical Reactivity of Hydrogen Storage Materials: Exploring Borohydride and Hydrazinium Salt Mixtures

Electrochemical characterization of hydrogen storage materials was conducted in a non-aqueous environment to investigate the direct electrochemical release and consumption of hydrogen and the potential for regeneration. We first address the challenge of minimal solubility of the synthetic precursors, sodium borohydride (NaBH4) and hydrazinium bromide (N2H5Br), in both organic and inorganic solvents. We next determine and calibrate a reference electrode formulation compatible with our non-aqueous media and analytes that demonstrates a stable reference potential. We employ cyclic voltammetry (CV) to characterize the precursors and mixtures thereof. Each CV peak is assigned to a corresponding electrochemical reaction. Using the rate-dependent CV method and Randles–Ševčík equation, we calculate the diffusion coefficient of each chemical (NaBH4 and N2H5Br). Analysis of the CVs, coupled with 11B NMR analysis, reveals a room temperature chemical transformation of NaBH4 and N2H5Br mixtures into hydrazine borane (N2H4BH3). These results are particularly significant, considering the limited information available on the electrochemical characterization of metal borohydride and hydrazinium salt in non-aqueous media. This work establishes a foundation for adapting a non-aqueous electrochemical system to further study the borohydride family of chemistries and to design and develop electrochemical devices for direct electrical and chemical energy interconversion with hydrogen storage materials.

Structural and Electrochemical Characterisation of NBZFO Cobalt-Free Cathode Material for Intermediate-Temperature Solid Oxide Fuel Cells: An Experimental Investigation

Compared to other energy-generating technologies and energy conversion devices, intermediate-temperature solid oxide fuel cells (IT-SOFCs) have gained significant attention from energy experts due to its high energy density, moderate operating temperature (600–800°C), low emissions and reliability. Enhancing the performance of IT-SOFCs requires suitable and excellent cathode materials. Thus, a perovskite-type Nd0.5Ba0.5Zr0.8Fe0.2O3+δ (NBZFO) material was synthesised via traditional solid-state reaction technique and analysed as a potential cathode material for IT-SOFCs. Analysis of X-ray diffraction data (XRD) revealed a single-phase perovskite material that crystallises in cubic space group (pm-3m). The thermal and electrochemical properties were analysed with the aid of thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). NBZFO has an electrical conductivity in air of 80 S cm−1 at 400°C and a polarisation resistance (Rp) of 0.106 Ω cm2 at 800°C. TGA reveals a slight loss in weight of about 0.58%, thereby suggesting a highly stable cathode material for IT-SOFC. Electrochemical investigation shows that NBZFO has good electronic and ionic conductivity and excellent oxygen stichometry. Further studies are required to understand the effects of varying B-site composition of the cathode material.

A comprehensive undergraduate experiment: preparation and chromatographic evaluation of a core-shell stationary phase based on a covalent organic framework

Continuously promoting new curriculum standards is a key aim of the Ministry of Education of China. With this in mind, this paper introduces a comprehensive teaching experiment for undergraduate instrumental analysis courses that aims to improve students' material-preparation and instrumental-analysis skills through practice. Herein, a covalent organic framework-based core-shell stationary phase material (SiO2@COFTTA-DHTA) is prepared via a one-pot method and characterized in detail, after which its chromatographic properties are evaluated by high performance liquid chromatography (HPLC). The experimental process includes material synthesis and characterization, as well as studying the chromatographic-retention behavior and chromatographic-separation performance of the material. By the combining theoretical science and experimental teaching, this experiment not only deepens students' understanding of the properties of functional materials and their applications, but also improves their experimental-design and critical-thinking skills. This experiment not only cultivates students' interests in scientific research, but also exercises their experimental, operational, innovative-thinking, and practical abilities, while concurrently enhancing their sense of social responsibility and historical mission, thereby delivering the all-round educational goals of experimental teaching.

Preface: 13th Ranshofener Leichtmetalltage

Abstract What strategies are available to minimize resource consumption in the light metal industry through recycling and energy efficiency? How can lightweight design make mobility more sustainable? And what role will artificial intelligence play in future processes in the metal processing industry? These and other questions are addressed at the 13th Ranshofener Leichtmetalltage 2024, which take place on the 26th–27th of September 2024 at the Hotel Gut Brandlhof in Saalfelden, Austria, and are organized in accordance with the criteria of the Austrian Ecolabel for Green Events. Under the guiding theme of “Light Metals Innovations for Environmental and Economic Sustainability”, this year’s conference offers an exciting program in three sessions “Digitalization in the Context of Circularity”, “Sustainable Process Development” and “Innovative Light Metals and their Characterization”. The focus is on decarbonization and digitalization in process and material development as well as the material characterization of light metals. A balanced spectrum of international presentations from universities, RTOs and industry provides participants with an up-to-date overview of the latest scientific findings and successful light metal applications. The 13th Ranshofener Leichtmetalltage 2024 are thus clearly focused on decarbonization and digitalization – even in times of diverse challenges. The first session, “Digitalization in the Context of Circularity”, highlights best-practice examples from the aluminium industry, the balance between sustainability and performance in metal processing and the implementation of complex geometries using wire-based additive manufacturing. The second session, “Sustainable Process Development”, is dedicated to the decarbonization and reduced material consumption of industrial processes, for example through GigaCasting, or the use of innovative recycling technologies. The third session, “Innovative Light Metals and their Characterization”, addresses forward-looking topics such as the development of special aluminium alloys for additive manufacturing, the use of old car scrap for innovative alloys and the decarbonization of the magnesium industry. The conference proceedings contain scientific contributions to the conference. We would like to thank all the authors for their high-quality work and the participants of the 13th Ranshofener Leichtmetalltage 2024 for their interest. We wish you stimulating reading and creative impulses! List of Scientific committee, Organizing committee are available in this Pdf.

Enhancing photovoltaic cell design with multilayer sequential neural networks: A study on neodymium-doped ZnO nanoparticles

Multilayer sequential neural networks, a powerful machine learning model, demonstrate the ability to learn intricate relationships between input features and desired outputs. This study focuses on employing such models to design photovoltaic cells. Specifically, neodymium (Nd)-doped ZnO nanoparticles (NPs) were utilized as a photoanode for fabricating dye-sensitized solar cells (DSSCs). A natural dye extracted from Spinacia oleracea was employed, while two types of electrolytes, liquid and gel (polyethylene glycol-based), were used for comparative analysis. Extensive material characterization of the photoanode highlights the impact of Nd content on the physicochemical properties of ZnO. Notably, when the doped photoanode and gel electrolyte were combined, a substantial 110% improvement in power conversion efficiency (PCE) was achieved. Building on these findings, the machine learning model in this research accurately predicts the current-voltage (I-V) curve values for such photoanodes, with an impressive accuracy of 98%. Additionally, the model illuminates the significance of variables like crystal distortion, texture coefficient, and doping concentration, underscoring their importance in the context of photovoltaic cell design.

Design, fabrication, and characterization of 1–3 piezoelectric composite air-coupled ultrasonic transducers with micro-membrane filter matching layer

Air-coupled ultrasonic transducers are widely used in various fields of nondestructive material characterization. This paper presents the fabrication and performance characterization of 1–3 piezoelectric composite air-coupled ultrasonic transducers operating at frequencies ranging from 400 kHz to 600 kHz. The transducers are fabricated using a dice-and-fill method with PZT-5 as the active material. A double-layer matching strategy is employed, utilizing hollow glass microsphere filled epoxy resin as the first matching and bonding layer. Additionally, micro-membrane filters with different pore sizes are used as the second matching layer. Thermoplastic adhesive TPU is utilized to bind the micro-membrane filter and the first matching layer. Due to the low acoustic impedance of the hollow glass microsphere filled epoxy resin and micro-membrane filter, acoustic impedance mismatch is reduced. Finite element simulation is used to determine the optimal ceramic volume fraction and ceramic pillar height of the 1–3 piezoelectric composites. When the pore size of the micro-membrane filter is 0.8 μm, the transducer achieves the lowest two-way insertion loss of −56.86 dB and the highest −6 dB bandwidth of 15.6 %, making it feasible for through mode applications.

Innovative synthesis of ternary heterojunction CuInS2/BiOI/Bi2MoO6 for 2,4-DCP degradation and its dechlorination performance

This study focuses on a novel ternary heterojunction catalyst for the removal of 2,4-dichlorophenol (2,4-DCP), an organic pollutant that is difficult to degrade. An efficient CuInS2/BiOI/Bi2MoO6 ternary heterojunction photocatalyst was formed by constructing a CuInS2/BiOI composite layer on a Bi2MoO6 substrate using an in-situ growth technique. The microstructure and photoelectric conversion properties of the catalysts were comprehensively resolved by systematic material characterization, including scanning electron microscopy (SEM) observation, X-ray photoelectron spectroscopy (XPS) analysis and photoelectrochemical testing. The experimental results showed that the optimized catalyst at a loading of 2.0 g/L exhibited excellent photocatalytic degradation efficiency against 20 mg/L concentration of 2,4-DCP at neutral pH, reaching 80.3 % degradation rate in 120 min. This high performance was mainly attributed to the enhanced charge-carrier separation mechanism at the heterojunction interface, which effectively enhanced the utilization and transfer rate of photogenerated electron-hole pairs and enhanced the photocatalytic activity of the catalyst. In addition, the study also deeply explored the conversion pathway of elemental chlorine in the photocatalytic system, elucidated the mechanism of 2,4-DCP degradation and dechlorination, and provided a theoretical basis for further improving the environmental adaptability and dechlorination efficiency of the catalyst. Overall, the CuInS2/BiOI/Bi2MoO6 ternary heterojunction photocatalysts proposed in this study demonstrate a broad application prospect in the purification of 2,4-DCP and other organic pollutants, and open up a new way to solve the problems of industrial wastewater treatment, which is of great environmental significance and scientific value.

Supplying active lithium to single-crystal Li(Ni0.90Co0.05Mn0.05)0.98Ta0.02O2 with Li2MnO3 coating served as cathode for Li-ion batteries

Ni-rich layered oxide with Ni molar content larger than 90% was regarded as an extremely promising candidate for cathode material applied in lithium-ion batteries owing to the significant discharging capacity and low cost. Nevertheless, rigorous cycling attenuation resulted from the crystal structure collapse and unstable particles interface deeply restrained the commercial application. In the work, LiNi0.90Co0.05Mn0.05O2 was modified by Ta5+ doping and Li2MnO3 covering, which was aimed to enhance the structure stability, defend the electrolyte attacking and promote Li+ migration during cycling. The material characterization demonstrated the cathodes after Ta5+ doping delivered the larger cell lattice parameters and higher cation ordering, which was helpful to improve the rate property and discharge capacity at low temperature. The Li2MnO3 layer was tightly adhered on the outside of LiNi0.90Co0.05Mn0.05O2, which could effectively relieve the electrolyte attacking and sustain the particle morphology integrity. As a result, 2wt.% Li2MnO3 coated Li(Ni0.90Co0.05Mn0.05)0.98Ta0.02O2 exhibited the outstanding discharge capacity of 150.2 mAh g−1 at 10.0 large current density and 140.6 mAh g−1 at -30 °C as well as the remarkable capacity retention of 93.1% after 300 cycles. Meanwhile, the pouch full batteries obtained by 2wt.% Li2MnO3 coated Li(Ni0.90Co0.05Mn0.05)0.98Ta0.02O2 also showed the more stable storage capability, cyclic property in comparison with bare LiNi0.90Co0.05Mn0.05O2.

Tribological Analysis of Surface Textures in Porcelain Tiles for Enhancing Pedestrian Walkway Safety

Due to their durability and aesthetic appeal, porcelain tiles have become a staple in modern construction and interior design. However, the persistent challenge of mitigating slip hazards, particularly in moist conditions, remains a critical concern for pedestrian safety. This study investigates the slip resistance performance of porcelain tiles, focusing on the influence of varying surface textures. The study clarifies the intricate relationship between surface texture and slip resistance through comprehensive dynamic friction tests involving four distinct porcelain tile samples and three different shoe samples conducted under arid, damp, and lathered conditions. While dry conditions showcase robust traction, moist environments underscore the significance of surface textures in enhancing grip. Moreover, the study introduces an operational scale of surface roughness, delineating optimal texture boundaries for maximal slip resistance. The implications of these findings extend beyond mere material characterisation, offering actionable insights for architects, designers, and safety professionals to enhance pedestrian safety in diverse settings. By bridging the gap between material science and real-world safety concerns, this research paves the way for innovative porcelain tile designs that prioritise safety without compromising aesthetic appeal.

Advanced Electrochemical Detection of 2,4-dichlorophenol in Water with Molecularly Imprinted Chitosan Stabilized Gold Nanoparticles

2,4-Dichlorophenol (2,4-DCP) is a hazardous chemical that can be passed down to offspring. Because 2,4-DCP degrades slowly and can be passed down to future generations, it’s a pesticide that needs to be continuously monitored and managed. With the use of chitosan-stabilized AuNPs on a glassy carbon electrode and the molecular imprinting technique, an effective electrochemical sensor has been built for the selective determination of 2,4-DCP in different aqueous samples. The analyte’s electroactive surface area and number of interaction sites are both increased by the AuNPs. The formulated AuNPs were characterized using several material characterization techniques. Molecularly imprinted nanomaterials provided the selectivity against other interfering chlorophenols. With a detection limit of 6.33 nM and a broad linear dynamic range of 21.09 to 310 nM, 2,4-DCP was found using differential pulse voltammetry. Without interference from structural analogs, the sensor was effectively evaluated in a variety of contaminated water samples.

Constructing a Z-scheme heterojunction of oxygen-deficient WO3-x and g-C3N4 for superior photocatalytic evolution of H2

Semiconductor-based photocatalytic water splitting enables the conversion of abundant solar energy to green and renewable hydrogen energy. Graphitic carbon nitride (g-C3N4) is synthesized using a straightforward method, demonstrating stable physicochemical properties and possessing an optimal bandgap, thus positioning it as a promising photocatalyst in the realm of environmental sustainability. Oxygen vacancies are extensively employed to modulate light absorption and surface properties of metal-oxide semiconductors. In this study, g-C3N4 nanosheets were coupled with oxygen-deficient tungsten trioxide (WO3-x) to form heterojunction photocatalysts (X-WOCN). Comprehensive material characterization results demonstrated that the constructed heterojunction extended the visible light absorption range, improved photogenerated electron-hole separation efficiency, and thus augmented photocatalytic activity. Notably, the optimum hydrogen evolution rate of 6%-WOCN was enhanced by 5.4-fold compared to that of g-C3N4. Furthermore, we propose a Z-scheme heterojunction charge separation mechanism mediated by oxygen defects and support this mechanism through detection of surface-active substances •O2− and •OH. This study offers novel propositions into the function of oxygen defects in facilitating charge separation within Z-scheme heterojunction.

Carbothermally synthesized, lignin biochar-based, embedded and surface deposited nano zero-valent iron composites: Comparative material characterization, selective gas adsorption and nitroaromatics remediation

Biochar (BC) with nanoscale zero valent iron (nZVI) incorporation offers advantageous materials for water purification. Even though the most common approach for nZVI incorporation is the deposition on the carrier surface, embedding in the support matrix has also been reported. However, the behavior of the embedded material in contaminant removal has not been adequately studied while characteristics and the remediation capabilities of the two materials have not been compared. Present study focuses on preparing and extensively characterizing two materials: nZVI embedded in (Lig-e-nZVI) and surface deposited on (Lig-s-nZVI) lignin BC with subsequent comparative study of remedial action for two nitroaromatics, p-nitroaniline (pNA) and p-nitrophenol (pNP). The synthesis of Lig-e-nZVI and Lig-s-nZVI involved simultaneous and subsequent pyrolysis of lignin and carbothermal reduction of the iron salt, respectively. Lig-e-nZVI showed enhanced porosity. XRD confirmed the formation of Fe0. HR-TEM images proved the core-shell structure of nZVI, and an interlayer spacing of 0.36nm of the shell verified that the Fe0 particles are encapsulated with graphene while an iron carbide inner layer was also observed, thinner in Lig-e-nZVI and thicker in Lig-s-nZVI. Band gap energy of 2.54eV suggested a photocatalytic activity of both materials. Best fitted Sips isotherms showed 23.1 and 13.1mgg-1 capacities for Lig-s-nZVI in pNP and pNA adsorption respectively. Highest stability was portrayed by Lig-e-nZVI over 4 regeneration cycles. The physicochemical features of the developed materials further enable selective gas adsorption. Findings provide new insights into physicochemical characteristics and remedial actions of differently synthesized nZVI-BC composites.

Degradation of organic dyes by Peroxymonosulfate activated with Zn/Co-ZIF

In this study, we successfully synthesized a bimetallic metal-organic framework material Zn/Co-ZIF to start Peroxymonosulfate (PMS) for organic dye degradation in the water body. Material characterization was evaluated by advanced methods, such as XRD, FT-IR, SEM, EDX, and BET. The influence of different factors on methylene blue (MB) decomposition rate was investigated. The results show that Zn/Co-ZIF has a porous structure, a high specific surface area and decomposes 98.22% MB (20 mg/L) in 4 minutes under reaction conditions of 40 mg/L catalyst, 0.814mM PMS, pH = 7. The decomposition efficiency of dyes increases in the order CR (79.85%) <RhB (90.81 %) < DB71 (96.07%) < MO (97.63%) < MB (98.22%). The main ROS for the degradation MB in this study were SO4—-, O2—- and 1O2. This shows that Zn/Co-ZIF materials are potential heterogeneous catalysts to activate PMS to decompose organic pollutants in water.

Multifunctional characterization of cement-Sargassum composites for application as bioconstruction materials

Utilizing solid waste biomass developing of construction materials presents an environmental mitigation opportunity by gradually replacing conventional materials that generate diverse ecological impacts. This approach aligns with circular economy and green chemistry principles, promoting the creation of sustainable materials. This research analyzes the use of brown algae from the Sargassum genus for bioconstruction applications through its mix with Portland cement. The mass influx of pelagic Sargassum species onto Caribbean beaches since 2011 has significantly impacted the environment, economy, and human health. The valorization of Sargassum is crucial for effective management and impact reduction. The study encompasses four key stages: (a) collection and processing of the algae, (b) development of a construction material composed of Portland cement and Sargassum at concentrations of 5 wt.% and 7.5 wt.%, (c) multifunctional characterization of the composite material, encompassing physical chemistry and thermal, optical and mechanical properties, and (d) an economic-environmental evaluation of using the construction material for housing in the Mexican Caribbean to enhance thermal insulation and reduce electric energy consumption associated with air conditioning. Test specimens of the composite material reveal compressive strength ranging between 78 and 347 kg/cm2, solar spectrum absorbance between 54% and 70%, and thermal conductivity between 0.65 and 1 W/mK. The economic-environmental analysis indicates that employing the construction material in 5% of households in the state of Quintana Roo, Mexico, could lead to annual reductions in energy consumption of approximately 67 GWh, with savings exceeding US$33,000, and environmental yearly mitigation equivalent to 4.1 TnNOx, 5.2 TnCH4, and 33,262 TnCO2. These results suggest promising prospects for incorporating Sargassum into construction materials, offering potential environmental and economic benefits. The composite material demonstrates optical, thermal, and mechanical functionality.

Experimental characterization of acoustic damping materials

AbstractDue to their ease of use and low cost, passive damping methods are a preferred mean for the reduction of noise in many engineering applications. This applies in particular to foam materials, which exhibit good acoustic and mechanical damping properties. The selection of suitable materials is usually carried out experimentally and can be very labor‐intensive and time‐consuming. For this reason, it is helpful to develop qualified numerical methodsthat can be used for material design and selection. Hence, foam materials must be characterized experimentally in order to enable a later comparison with vibroacoustic simulations. This contribution, therefore, aims at providing suitable parameters for the use in numerical analyses and their validation. Firstly, the microstructure of a foam specimen is captured by means of a CT scan. In addition to providing the geometry for the multi‐physics simulations, this measurement is also used to determine characteristic foam features, for example, strut thickness and pore size distribution. In the second step, the frequency‐dependent stiffness and damping properties of the material are determined by a special experimental setup utilizing an electrodynamic shaker. Here, the dynamic system is approximated as a single‐mass oscillator, which is sufficiently accurate for low frequencies. These properties will later be used in the numerical model to evaluate different parameter identification approaches. In the third and last step of the experimental campaign, measurements with an impedance tube are conducted to obtain the coefficient of absorption. This material parameter is particularly suitable for comparing experiments and simulations. Finally, the correlation between the experimental results is examined to provide a deeper understanding of the foam materials.

Highly sensitive electrochemical sensor based on flexible porous graphene for cortisol detection

This report presents the development of an electrochemical sensor for detecting cortisol in sweat, utilizing a flexible porous graphene electrode (fPGE). The fPGE was created using the laser-induced graphene technique on a polyimide substrate. The characterization of the porous graphene material was conducted through SEM and Raman spectroscopy. The graphene surface of the fPGE was modified with cortisol-aptamer with the assistance of linker molecules, PASE, to form the cortisol sensor. The electrochemical properties of the sensor were assessed using cyclic voltammetry technique (CV). Cortisol detection in the sensor was achieved indirectly via the reaction of the redox couple K4[Fe(CN)6]/K3[Fe(CN)6] on the surface of the cortisol aptamer-modified fPGE. As the concentration of cortisol in the solution increased, the corresponding current in the CV decreased. Under optimized conditions, the electrochemical cortisol sensor demonstrated a wide dynamic range of cortisol concentration from femtomolar (fM) to micromolar (µM) with a low limit of detection (LOD) of 100 fM.

Impact of Encapsulated Phase Change Material Additives for Improved Thermal Performance of Silicone Gel Insulation

Abstract Passive cooling through phase change materials (PCM) creates beneficial complimentary cooling techniques aimed at providing thermal gradient mitigation during device operation without additional power requirements. These have been well studied but are difficult to implement due to complications concerning effective enclosure of the liquid phase. Encapsulated PCM particles can be embedded in other materials to form composites with form stable solid–liquid phase transitions. This study characterizes a new composite of silicone gel and encapsulated phase change materials (ePCMs) for use as an encapsulant. The ePCMs contain a paraffin core and titania shell resulting in a self-contained solid–liquid phase transition producing an average of 132.9 J/g of latent heat capacity. The gel composites gain latent heat capacity as a linear function of ePCM concentration by weight. The 30% ePCM sample contains 41.0 J/g of latent heat capacity, approximately 30% of ePCM control samples. The specific heat capacity of the silicone gel without ePCMs is 1.539 J/g-° C and 2.825 J/g-° C for the ePCM particles. As the ePCM concentration increases, the specific heat capacity is increased toward the highest value of the pure ePCMs across all temperature ranges. The coefficient of thermal expansion of the composites is increased with ePCM concentration up to a maximum of 96% in the 20% ePCM concentration. The elastic modulus remains relatively constant across ePCM concentrations and temperatures. In the needle–needle breakdown voltage testing the 20% sample has a 6 kV/mm reduction in dielectric strength and higher than 20% ePCM samples show increased variability in strength due to the dispersed particles. Overall, the results from these material characterizations demonstrate the promise of dielectric composites containing ePCM particles to add passive cooling capability into electronics devices without complex structures.

Nanoarchitectonics of Biofunctionalized Hydrogen‐Terminated 2D‐Germanane Heterostructures as Highly Sensitive Biorecognition Transducers: The Case Study of Cocaine Drug

Hydrogen‐terminated 2D‐germanane (2D‐GeH), as one inorganic 2D material akin to graphene, is attracting widespread interest owing to its predicted (opto)electronic properties. Nonetheless, the chemical reactivity of 2D‐GeH requires further exploration to expand its real implementation. Herein, a simple and straightforward bottom‐up biofunctionalization approach is reported aiming at providing the bases toward the robust design of 2D‐GeH‐based biorecognition systems with electrical readout. For this goal, 2D‐GeH has been firstly functionalized with gold nanoparticles (Au‐NPs) via an organometallic approach, followed by the covalent immobilization of a thiolated single‐stranded DNA (ssDNA) aptamer via AuS bond interactions. After an accurate material characterization, the resulting ssDNA/Au@GeH heterostructure is drop‐casted on a fluorine‐doped tin oxide (FTO) electrode for impedimetrically monitoring cocaine as a model drug. Interestingly, the aptamer–cocaine interactions hinder the interfacial electron‐transfer process of the benchmark [Fe(CN)6]3−/4− redox marker with increasing concentration of the cocaine target, leading to a detection limit as low as 4.9 ± 0.1 aM, the lowest one reported in literature by far. Overall, the ssDNA/Au@GeH electrochemical biosensor exhibits outstanding selectivity, specificity, and reproducibility, demonstrating the potential use of 2D‐GeH as an emerging highly sensitive transducer for biosensing applications. The reported method is general and might be simply customized by tailoring the biorecognition component.