Phase Transition Properties Research Articles

Surface Nanopatterning and Structural Coloration of Liquid Metal Gallium Through Hypergravity Nanoimprinting

AbstractNanoscale structuring of gallium‐based liquid metals has emerged as a promising approach for generating unique properties and functionalities in advanced materials and devices. However, their exceptionally high surface tension presents significant challenges for achieving surface nanostructuring using conventional fabrication techniques. Here, a hypergravity nanoimprinting method is introduced, which harnesses horizontal centrifugation to generate hypergravity fields that drive liquid gallium into nanoscale cavities on an elastic polymer stamp surface at subzero temperatures, where it solidifies and preserves imprinted features down to 100 nm lateral resolution. This surpasses previous limits of gallium patterning, enabling phenomena such as iridescent structural colors with a wide range of hues and high saturation. Numerical simulations reveal the intricate fluid dynamic behaviors and interfacial interactions during the imprinting process, providing valuable insights for process optimization and control. By synergistically combining advanced soft lithography techniques with the reversible solid‐liquid phase transition properties of liquid metals, hypergravity nanoimprinting offers a practical nanofabrication approach, facilitating the development of next‐generation nanoscale gallium devices with finely structured nanofeatures across diverse application domains, such as nanoelectronics and photonic metamaterials.

Solid-State Reversible Phase Transition and Photoluminescence Properties of Organic-Inorganic Hybrid Halide: (BTPA)2MnBr4.

Multifunctional materials have long been a popular research area, with organic-inorganic hybrids frequently utilized due to their diverse properties and versatile assembly techniques. In this context, a novel Mn-based organic-inorganic hybrid compound (BTPA)2MnBr4(1) was prepared, with strong green photoluminescence, phase transition under thermal stimulation, and two reversible dielectric-state switches. This compound exhibits strong green photoluminescence under ultraviolet excitation, boasting a quantum yield of 44.36%. Furthermore, it demonstrates a reversible ferroelastic phase transition at 358/348 K. The integration of temperature and photosensitivity in compound 1 opens up new avenues for the development and exploration of a broader spectrum of multifunctional phase transition materials.

Expanded graphite encapsulation of nitrates for enhanced thermal transport: Mechanism insight and component screening

The efficient improvement of the heat transfer capability of high-temperature molten salts and the accurate measurement within the operating temperature range is vital for improving the efficiency of concentrating solar power devices. Through theoretical investigation, this paper explores different thermal properties including thermal conductivity, phase transition properties and interfacial interactions using a range of expanded graphite/nitrates (EG/nitrates). Molecular dynamics simulations reveal that the EG/eutectic salt (ES) exhibits optimal comprehensive properties. Experimentally prepared EG/ES composite phase change materials (PCMs), coupled with theoretical predictions, demonstrate exceptional thermal conductivity (2.2 W m−1 K−1) and a significant latent heat of phase change (>80 J g−1). The calculation results of the interaction energy between the host-guest indicate that the strong interaction of the EG to ES restricts the molecule movement, leading to a weak temperature dependence of the thermal conductivity of the EG/ES composite PCM. This contrasts with the conventional understanding of PCM thermal conductivity, which typically exhibits a sharp change during the phase transition from solid state to liquid state. Additionally, the thermal response of 15 wt% EG/ES is increased by 27.2 % compared to pure ES, which effectively helps alleviate local overheating in practical applications. The progress made so far sheds light on the mechanism behind the improved heat transfer and storage performance of nitrate from a microscopic view, offering valuable theoretical insight for developing high-efficient nitrate PCMs in solar thermal power generation systems.

Phase transition mechanism and property prediction of hafnium oxide-based antiferroelectric materials revealed by artificial intelligence

Phase transition mechanism and property prediction of hafnium oxide-based antiferroelectric materials revealed by artificial intelligence

Comparison of the activity of two elastin-like recombinant carriers fused to the antimicrobial peptide indolicidin.

Recombinant fusion biotechnology is a powerful tool for producing antimicrobial peptides (AMPs), which can contribute to limiting the number of potentially infectious microorganisms. AMPs are often expressed in fusion with a carrier protein, a strategy that prevents toxic effects on host bacterial cells and protects them from proteolytic degradation. Among the many fusion carriers available, elastin-like polypeptides offer several valuable advantages related to their unique thermo-responsive behavior. The Human Elastin-like Polypeptide was successfully employed to produce a model fusion construct with the indolicidin domain. Recently, an elastin-based variant of this polypeptide was developed, modulating the sequence of the hydrophobic domains, thus enhancing the phase transition properties. Here, a new carrier based on this sequence that was produced, physicochemically characterized, and employed as a fusion partner for the indolicidin is described. This work aims to compare two different elastin-based carriers and their indolicidin fusion derivatives, as well as to determine, based on their properties, which may be the most advantageous carrier for producing antimicrobial domains. This study was focused on the elastin-like polypeptides as a tunable expression platform particularly suitable for producing AMPs and for their integration in biomimetic interfaces that acquire the capacity to inhibit bacterial growth.

Phase-transition metamaterial smart window for radiative cooling and privacy protection

This paper proposes a smart window for radiative cooling with adjustable transparency by leveraging the phase transition property of VO2. The proposed smart window exhibits daytime visible light transmission and near-infrared light reflection, all-day radiative cooling, and a nighttime privacy protection feature. It comprises a bottom layer of VO2/Ag/VO2 and top cubic two-dimensional SiO2 gratings, with structural parameters optimized by the genetic algorithm to ensure excellent optical performance. In the daytime, 75.4% visible light transmittance and 87.8% near-infrared reflectance can be achieved by utilizing the dielectric state of VO2. It also achieves low light transmission of 9.8% by using the metallic state of VO2, which is suitable for nighttime privacy protection. Furthermore, it has an all-day outside emissivity of 98.2% for radiative cooling, together with a low inside emissivity of 1.9% for effectively inhibiting the radiation heat transfer. In addition, the proposed structure is insensitive to the angles of incidence and the polarization of light, making it advantageous for radiative cooling. During the daytime, it reduces the temperature by 17.7 K compared to a glass of equal thickness when the non-radiative heat coefficient is 12 W/m2/K. At night, it achieves a cooling power of 124.7 W/m2, achieving a cooling effect of 8.9 K below ambient temperature. The proposed smart window is promising for various application scenarios for radiative cooling and privacy protection and could be used as windows for buildings and vehicles.

Flexible Continuum Robot with Variable Stiffness, Shape‐Aware, and Self‐Heating Capabilities

Conventional continuum robots have outstanding flexibility and dexterity. However, when the robot needs to interact with the environment, the softness may affect the performance of the robot. Especially in transport tasks, the softness of continuum robots can lead to handling failures and drastic drops in precision. The variable stiffness continuum robot combines the advantages of flexibility and rigidity, which is conducive to expanding the application scenarios of flexible continuum robots. This article proposes a flexible continuum robot that simultaneously realizes variable stiffness, shape‐aware, and self‐heating functions using liquid metal. The low‐temperature phase transition property of liquid metal is utilized to realize the variable stiffness function; the overall stiffness of the robot can reach the range of 18.5–183 N m−1, which can realize a tenfold stiffness gain. The conductivity of liquid metal is utilized to develop the shape‐aware function, and the monitoring accuracy is within 5%. At the same time, this article utilizes the liquid metal's resistive thermal effect to realize heating function, so that the robot no longer needs heating systems such as heating wires and can realize the phase transition by energizing itself. Based on this design, the robot arm can realize the transition between maximum and minimum stiffness within 240 s.

Modeling of the metal–insulator transition temperature in alio-valently doped VO2 through symbolic regression

The correlated semiconductor vanadium dioxide (VO2) exhibits an insulator–metal transition (IMT) near room temperature, which is of interest in various device applications. Precise IMT temperature control is crucial to determine the use cases across technologies such as thermochromic windows, actuators for robots or neuronal oscillators. Doping the cation or anion sites can modulate the IMT by several tens of degrees and control hysteresis. However, modeling the effects of control parameters (e.g., doping concentration, type of dopants) is challenging due to complex experimental procedures and limited data, hindering the use of traditional data-driven machine learning approaches. Symbolic regression (SR) can bridge this gap by identifying nonlinear expressions connecting key input parameters to target properties, even with small data sets. In this work, we develop SR models to capture the IMT trends in VO2 influenced by different dopant parameters. Using experimental data from the literature, our study reveals a dual nature of the IMT temperature with varying tungsten (W) doping concentrations. The symbolic model captures data trends and accounts for experimental variability, providing a complementary approach to first-principles calculations. Our feature-driven analysis across a broader class of dopants informs selectivity and provides qualitative insights into tuning phase transition properties valuable for neuromorphic computing and thermochromic windows.

Bifunctional terahertz metamaterial device with switchable properties between transmission and broadband absorption

A bifunctional terahertz metamaterial device with switchable properties between transmission and broadband absorption is proposed. The simulated results show that the switchable functional characteristics of the bifunctional terahertz metamaterial device can be achieved by taking advantage of the phase transition property of VO2. When VO2 is in the insulating state, there are transmission spectra with a maximum transmittance of 90 % and a minimum transmittance of 25 % in the frequency range from 1 THz to 10 THz. Meanwhile, transmission spectra be adjusted by controlling the Fermi level of graphene. When VO2 is in the fully metal state, the broadband absorptivity achieves over 90 % in the frequency range from 2.54 THz to 7.65 THz. Not only that, the absorption spectra can be continuously adjusted by controlling the conductivity of VO2 from 20 to 200000 S/m. Alternatively, the proposed bifunctional terahertz metamaterial device can work and show the same absorption spectra when the conductivity of VO2 is 200000 S/m under TM and TE polarized normal incidences. Our current research work has a potential to provide a valuable reference for the advancement of transmissive and broadband absorbent metamaterial devices in the terahertz range.

Predicting p53-dependent cell transitions from thermodynamic models.

A cell's fate involves transitions among its various states, each defined by a distinct gene expression profile governed by the topology of gene regulatory networks, which are affected by 3D genome organization. Here, we develop thermodynamic models to determine the fate of a malignant cell as governed by the tumor suppressor p53 signaling network, taking into account long-range chromatin interactions in the mean-field approximation. The tumor suppressor p53 responds to stress by selectively triggering one of the potential transcription programs that influence many layers of cell signaling. These range from p53 phosphorylation to modulation of its DNA binding affinity, phase separation phenomena, and internal connectivity among cell fate genes. We use the minimum free energy of the system as a fundamental property of biological networks that influences the connection between the gene network topology and the state of the cell. We constructed models based on network topology and equilibrium thermodynamics. Our modeling shows that the binding of phosphorylated p53 to promoters of target genes can have properties of a first order phase transition. We apply our model to cancer cell lines ranging from breast cancer (MCF-7), colon cancer (HCT116), and leukemia (K562), with each one characterized by a specific network topology that determines the cell fate. Our results clarify the biological relevance of these mechanisms and suggest that they represent flexible network designs for switching between developmental decisions.

Phase-space path integral approach to the kinetics of black hole phase transition in massive gravity

The dynamics of the state-switching process of black holes in dRGT massive gravity theory is presented using free energy landscape and stochastic Langevin equations. The free energy landscape is constructed using the Gibbons-Hawking path integral method. The black hole phases are characterized by taking its horizon radius as the order parameter. The free energy landscape provides three black hole phases: small, intermediate, and large. The small and large black holes are thermodynamically stable whereas the intermediate one is unstable. The Martin–Siggia–Rose–Janssen–de Dominicis (MSRJD) functional describes the stochastic dynamics of black hole phase transition. The Hamiltonian flow lines are obtained from the MSRJD functional and are used to analyze the stability and the phase transition properties. The dominant kinetic path between different phases is discussed for various configurations of the free energy landscape. We discuss the effect of black hole charge and the graviton mass on the critical behavior of black hole phase transition.

Preface

Abstract With the continuous changes in material demand and the development of related disciplines driven by economic and social development, in recent years, material research has shown some new trends. The deep integration of material technology and information technology has deepened our understanding of material structure and performance, leading to more precise control over the material preparation process and functionality. The conference shares practical experiences and enlightening ideas from mateirals physics and appliacations and will be of interest to researchers in and practitioners everywhere. Keynote speakers includes Prof. Junhui Hu, from Nanjing University of Aeronautics & Astronautics, China, Prof. Karamanis Dimitrios from University of Patras, Greece, Prof. Osman Adiguzel from Firat University, Elazig, Turkey. The proceedings present papers from the International Conference on Materials Physics and Applications, held in Xi’an during 1-3 October, 2024. All papers were carefully reviewed by the technical program committee (TPC) and reviewers, bearing in mind the quality, novelty, breadth and depth of the research themes which fall into the ICMPA scope. The topics of papers accepted in the Proceedings of ICMPA 2024 can be classified as Material Modeling and Application, Phase Transition and Mechanical Properties of Materials, Glasses & Ceramics, Composites Materials. Furthermore, we are very grateful to everyone, especially the program committee members and reviewers, who devoted time to assess the papers. Our particular thanks and regards also go to the Journal of Physics: Conference Series, for supporting this conference. List of Conference Committees are available in this Pdf.

Order phase transition of HIP nickel-based powder superalloy during isothermal aging

Nickel-based powder superalloys have become one of key materials for aerospace turbine engines due to their excellent comprehensive properties. The microstructure stability during long-term isothermal aging is closely related to mechanical properties. The correlation between order phase transition and mechanical properties of a HIP (hot isostatic pressing) nickel-based powder superalloy after long-term isothermal aging treatment was investigated. The results show that the decomposition of MC carbides and precipitation, growth and coarsening of γ' phases occur with duration of isothermal aging. Tertiary γ' phases precipitates by the way of element diffusion with γ' phases coarsening. In addition, strengthening mechanism is quantitatively calculated, and the relative contribution of γ' phases to yield strength is largest, and multi-mode size of γ' phases are favorable to yield strength and hardness of HIP nickel-based powder superalloy.

Enhancing the Purification and Stability of Superoxide Dismutase by Fusion with Thermoresponsive Self‐Assembly of Elastin Like Polypeptide

AbstractElastin‐like polypeptide (ELP) is a thermo‐sensitive biosynthetic polymer composed of a Val‐Pro‐Gly‐Xaa‐Gly repeating unit possessing a sharp reversible phase transition property at specific temperatures. Here, ELP was fused to human superoxide dismutase 1 (hSOD1) modified with His tag to produce recombinant hSOD1‐Linker‐ELP‐His (hSODLEH) which was expressed in E. coli and purified via inverse thermal cycling (ITC) and Ni‐NTA resin. The results showed that ELP tag did not affect the soluble expression of SOD1. The purification by ITC was superior to Ni‐NTA resin due to its convenient purification process, improved recovery rate and purification fold, thus indicating industrial suitability for large scale protein purification in a cost‐ and time‐efficient manner. Moreover, one round of ITC was sufficient for the recovery of highly purified recombinant SOD. The results further showed that ELP improved the stability of the SOD, and did not affect its secondary structure nor its ability to bind divalent metal ions. Overall, ELP‐protein fusion system could be a promising tool for large scale enzyme purification.

A dynamically switchable and tunable metamaterial device based on vanadium dioxide and Dirac semimetal

In this paper, a dual-function metamaterial device based on vanadium dioxide (VO2) and Dirac semimetal (DS) operating in terahertz (THz) frequency range is designed. The reversible phase transition properties of VO2 are exploited to achieve the dynamic switch between the function of broadband absorption and broadband polarization conversion. It is demonstrated that when VO2 is in the metallic state and the Fermi energy level () of DS is set to 30 the broadband absorption in the operating frequency range of 1.42-3.40 THz can be achieved, and its absorbance exceeds 90% with a relative bandwidth of 82.16%. When VO2 is in the insulating state and the of DS is set at 180 , the high efficient broadband polarization conversion can be obtained in the operating frequency range of 2.08-4.88 THz and the polarization conversion ratio (PCR) is greater than 90% with a relative bandwidth of up to 80.46%. Therefore, the proposed switchable dual-functional THz device can be extensively utilized in absorption, polarization conversion and other potential fields.

Magnetic phase transition and cryogenic magnetocaloric properties in the RE6Ni2.3In0.7 (RE = Ho, Er, and Tm) compounds

Magnetic phase transition and cryogenic magnetocaloric properties in the <i>RE</i>6Ni2.3In0.7 (<i>RE </i>= Ho, Er, and Tm) compounds

Unlocking Industrial Potential: Phase-Transition Coimmobilization of Multienzyme Systems for High-Efficiency Uridine Diphosphate Galactose Production.

Transitioning from batch to continuous industrial production often improves the economic returns and production efficiency. Immobilization is a critical strategy that can facilitate this shift. This study refined the previously established method for synthesizing uridine diphosphate galactose (UDP-Gal) by employing thermophilic enzymes. Three thermophilic enzymes (galactokinase, uridine diphosphate glucose pyrophosphorylase, and inorganic pyrophosphatase) were coimmobilized on the pH-responsive carrier Eudragit S-100, promoting enzyme recovery and reuse while their industrial potential was assessed. The coimmobilization system efficiently catalyzed UDP-Gal production, yielding 13.69 mM in 1.5 h, attaining a UTP conversion rate of 91.2% and a space-time yield (STY) of 5.16 g/L/h. Moreover, the system exhibited exceptional reproducibility, retaining 58.9% of its initial activity after five cycles. This research highlighted promising prospects for coimmobilization in industrial synthesis and proposed a novel methodology for enhancing UDP-Gal production in the industry. In addition, the phase-transition property of Eudragit S-100 paves the way for further exploration with the one-pot synthesis of poorly soluble galactosides.

Lead-free semiconductor materials with high phase transition temperature: [1-Methylimidazole][SbBr4]

Semiconductor with structure phase change is a special multi-functional material, which plays an important role in the field of Solar Energy, information computing, sensor technology, artificial intelligence, etc. In this paper, the organic–inorganic lead-free semiconductor phase change material [1-Methylimidazole][SbBr4] (1) was successfully constructed. The IR, TGA, DSC, VT-PXRD, solid-state UV–vis spectroscopy and temperature dependence of dielectric constant were characterized and analysed. Single crystal X-ray diffraction shows that at 298 K, the space group is P21/c, the point group 2/m; an endothermic and exothermic peak appeared near 386 K and 367 K in the DSC heating–cooling cycles. Near the corresponding phase transition temperature point, compound 1 exhibits a significant reversible change in the dielectric platform. Interestingly, the band gap of compound 1 is about 2.53 eV. The existence of such interesting physical properties is closely related to the interaction between cations and anions in the molecule and the connection of internal hydrogen bonds. By constructing organic–inorganic hybrid semiconductor materials, we hope to obtain semiconductor materials with phase transition properties and actively explore and provide some ideas and support for the application of new high-tech materials.

Insight into the Structural and Magnetic Properties of PrZnSi and NdZnSi Compounds Featuring Large Low-Temperature Magnetocaloric Effects.

The magnetocaloric (MC) and magnetic phase transition (MPT) properties in various types of rare earth (RE)-based magnetic materials have been intensively investigated recently, which are aimed at developing suitable MC materials for low-temperature cooling applications and better elucidating their inherent physical properties. We herein provide a combined experimental and theoretical investigation into two new light RE-based magnetic materials, namely, PrZnSi and NdZnSi compounds, regarding their structural, magnetic, MPT, and low-temperature MC properties. Both of these compounds crystallize in an AlB2-type hexagonal structure with a symmetry of the crystallographic space group P6/mmm and reveal a typical second-order-type MPT with ordering temperatures (TC) at approximately 13.5 and 18.5 K for PrZnSi and NdZnSi compounds, respectively. Moreover, they all exhibit large reversible low-temperature MC effects and remarkable performances, which are identified by the parameters of maximum magnetic entropy changes, relative cooling power, and temperature-averaged entropy change (temperature lift 5 K). The deduced values of these MC parameters under a magnetic field change of 0-7 T reach 16.3 J/kgK, 294.46 J/kg, and 15.79 J/kgK for PrZnSi and 15.4 J/kgK, 284.84 J/kg, and 14.95 J/kgK for NdZnSi, respectively, which are evidently better than those of most updated light RE-based magnetic materials with remarkable low-temperature MC performances, indicating that PrZnSi and NdZnSi compounds hold potentials for practical cooling applications.

Study of B/M phase transition and phase transition properties of annealing-tuned high phase transition latent heat of W-VO2 nanorods

Vanadium dioxide (VO2) can spontaneously regulate solar heat according to the ambient temperature, and has great application potential as a candidate for smart glass. However, its Tc, ΔTc and ΔH cannot be coordinated at the same time, and commercial use is greatly hindered. W-doped VO2 powders were prepared by the hydrothermal method under an argon atmosphere. Nanoflowers, nanorods, and other morphologies of W-doped VO2 were characterized. The test results showed that W doping could reduce the Tc of VO2 to 33.5 °C, ΔTc < 10 °C, and with high ΔH (ΔH ≈ 36.98 J/g). The phase transition behavior and morphology change mechanism of W-doped VO2 were investigated. The transformation of B and M phases was controlled by changing the annealing temperature, and W-VO2(M) powders with good phase transition properties were finally produced to meet the requirements of the practical application of smart glass materials.