Reversible Properties Research Articles

Synthesis of Regular Ladder-Type Fluorenylidene-Xanthene Oligomers via Nucleophilic Aromatic Substitution Reaction.

Fluorenylidene-xanthene and related polycyclic systems are typical examples of bistricyclic aromatic enes (BAEs); however, polycyclic systems of fluorenylidene-xanthene are relatively scarce. Here we synthesized a series of novel ladder-type polycyclic systems containing fluorenylidene-xanthene units, differing from the classic Barton's two-fold extrusion reaction. In the new synthetic scheme, the very popular Suzuki reaction was first used to couple the corresponding precursors, then a catalyst-free nucleophilic aromatic substitution reaction between Ar-F and Ar-OH groups in the backbone afforded ladder-type O-heteroarenes. Moreover, the new synthetic strategy is also suitable for the synthesis of other heterocyclic and polycyclic aromatic hydrocarbons. Some of these products showed reversible mechanochromism properties.

Identification and In Vitro and In Vivo Characterization of KAC-50.1 as a Potential α-Synuclein PET Radioligand.

The accumulation of aggregated α-synuclein (α-syn) is a pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. Here within, we report the in vitro characterization targeting site 2 of α-syn fibrils and in vivo evaluation of NHPs of KAC-50.1 as a potential α-syn positron emission tomography (PET) radioligand. Preclinical studies were performed using a multidimensional approach of post-mortem brain imaging techniques, radioligand binding, and biochemical studies. These experiments were followed by PET imaging in cynomolgus monkeys using [11C]KAC-50.1. [3H]KAC-50.1 displayed a KD of 35 nM toward site 2 in recombinant α-syn fibrils. Specific binding of [3H]KAC-50.1 was observed in brain tissues with abundant α-syn pathology but also in AD, PSP, and CBD cases, indicating binding to amyloid β (Aβ) and tau pathology. PET studies showed a rapid entrance of [11C]KAC-50.1 into the brain and relatively rapid washout from cortical brain regions, with slower washout in subcortical regions. [3H]KAC-50.1 is a ligand that binds to fibrillar α-syn but shows limited selectivity for α-syn versus Aβ and tau fibrils. PET studies in NHPs indicate that [11C]KAC-50.1, despite reversible kinetic properties, displays retention in white matter. Altogether, the in vitro and in vivo properties do not support further development of [11C]KAC-50.1 as a PET imaging agent.

Novel high-temperature thermochromic polydiacetylene material and its application as thermal indicator

The design and synthesis of organic high-temperature reversible thermochromic materials is one of the difficult issues in the field of organic chromic materials. In this paper, four diacetylene monomers named DBA-PCDA, TBA-PCDA, DBE-PCDA and TBE-PCDA, each containing multiple diacetylene units, were synthesized from 10,12-pentacosadiynoic acid (PCDA) through the amidation or esterification reactions, using 4,4′-diaminobiphenyl, 1,3,5-tris(4-aminophenyl)benzene, 4,4′-dihydroxybiphenyl, and 1,3,5-tris(4-hydroxyphenyl)benzene as bridging units. The effects of functional groups that can form hydrogen bond and π-π interactions on the solid-state polymerization properties of monomers and the thermochromic properties of the corresponding PDAs were investigated. The results show that only DBA-PCDA and TBA-PCDA, which contain functional groups that can form hydrogen bonding interactions, can be polymerized under 254-nm UV irradiation. The corresponding poly(DBA-PCDA) exhibits reversible thermochromic property even heated up to 200 oC, showing a potential application in the field of high-temperature thermal indicator above 100 °C. This work provides a new perspective to the development of PDA with high-temperature reversible thermochromic property.

Tunable macroscopic self-healing of supramolecular gel through host–guest inclusion

Supramolecular gels (SGs) consisted of noncovalent cross-linking network structures are fascinating due to their efficient energy dissipation and reversible self-healing properties. However, it is unknown how the noncovalent interactions alter the macroscopic self-healing and mechanical properties of SGs. Herein, the peculiar nature of SGs manufactured by combining covalent and noncovalent (host–guest inclusion of β-cyclodextrin and C16 hydrophobic chain) cross-linking structures was studied and compared with covalent cross-linking preformed particle gels. The macroscopic self-healing behaviors, rheology, mechanical tensile properties, as well as the tunable mechanisms of self-healing were explored by visual inspection, rheological, and atomic force microscopy probing methods. The results show that the SGs exhibit excellent self-healing efficiency and mechanical strength after interfacial cutting. Moreover, the SGs exhibited excellent mechanical tensile properties, including loading–unloading, successive loading–unloading, and recovery loading–unloading tensile performances. Notably, the macroscopic self-healing of SGs has good tunability by changing the covalent and noncovalent crosslinker contents and salt contents. This peculiar phenomenon is attributed to certain host–guest inclusion forces (4.7 and 0.3 nN) between different SGs under the distilled and high-salinity water conditions, respectively. This study is beneficial for the development of stimuli–response supramolecular gels in different applications, such as oil recovery in fractured reservoirs.

Close‐packed One‐dimensional Coordination Polymer Cathode with Fast Kinetics for Sodium‐ion Batteries

Sustainable sodium‐ion batteries (SIBs) have gained tremendous attention; however, the large‐sized Na+ poses serious challenges on the development of inorganic‐based cathodes. To overcome the issues, metal–organic electrode materials are appealing because they combine attractive characteristics of organic redox centers (e.g., flexibility, highly reversible redox properties, fast kinetics (regardless of size and charge of guest ions), structural/redox tunability, and resource abundance) with structural stability arising from metal‐ligand coordination. Herein, a one‐dimensional copper‒benzoquinoid coordination polymer (CP), [CuL(Py)2]n, (LH4 = 1,4‐dicyano‐2,3,5,6‐tetrahydroxybenzene, Py = pyridine) is investigated as cathode for SIBs. As opposed to most CPs reported for SIBs which possess high porosity and surface area, this close‐packed CP can deliver discharge capacity as high as 277 mAh g‒1 at 2C (~523 mA g‒1), and at extremely high rates of 50C and 300C (~13 and 78 A g‒1), reversible capacities of 131 and 74 mAh g‒1 still can be delivered, respectively. The transport kinetics of Na+ in [CuL(Py)2]n is found to be even faster than that of Li+ despite the close‐packed structure. The mechanistic and kinetic studies have been performed. The findings gained in this work undoubtedly unravel a potential design strategy for high‐performance metal–organic electrode materials for emerging post‐Li‐ion batteries.

Influence of an ultrathin Mn ‘spy layer’ on the static and dynamic magnetic coupling within FePt/NiFe bilayers

Abstract We explore whether insertion of an ultrathin Mn ‘spy layer’ within a magnetic hard/soft bilayer can enable depth-sensitive element-specific measurements of the static and dynamic magnetization, while avoiding significant disruption of the original magnetic state. MgO(110)/FePt(100 Å)/NiFe(200 Å)/Mn(tMn Å)/NiFe(200 Å) samples with Mn thicknesses of tMn=0, 5, and 10Å were fabricated by magnetron sputtering and studied by element-selective x-ray magnetic circular dichroism (XMCD), vector network analyzer ferromagnetic resonance (VNA-FMR), and x-ray detected ferromagnetic resonance (XFMR). For tMn= 5 Å, the magnetic reversal properties remain broadly similar to tMn= 0 Å. For tMn=10 Å, the two NiFe layers decouple with XMCD hysteresis loops at the Mn edge showing two switching events that suggest the presence of two distinct Mn-containing regions. While the Mn moments within each region have ferromagnetic order, their relative alignment is antiparallel at high field. Analysis of the magnetic data and additional scanning transmission electron microscopy (STEM) measurements point to the presence of a Mn layer at the lower NiFe/Mn interface, and the formation of a NiFeMn alloy at the upper Mn/NiFe interface. The Mn moments of the former region lie antiparallel to those of the underlying NiFe layer. The VNA-FMR data suggests that for tMn= 5 and 10 Å, the interfacial exchange coupling at the FePt/NiFe is suppressed and the in-plane uniaxial magnetic anisotropy of the NiFe is increased, perhaps due to migration of Mn towards the buried interface. The above findings show that Mn is a problematic magnetic spy, and that a Mn thickness of less than 5Å would be required.

Positional Isomerism Toward Tunable Organic Afterglow and Reversible Photoactivation Behavior for Anti‐Counterfeiting and Encryption

AbstractAchieving amorphous polymers with ultralong room‐temperature phosphorescence (RTP), tunable organic afterglow, and reversible photoactivation behavior is highly desirable for practical applications but challenging. Herein, simple positional isomers with three carboxyl groups located in the ortho, meta, and para positions of the triphenylamine skeleton are designed and synthesized. By physically blending with the poly(vinyl alcohol) matrix, these isomers show ultralong RTP properties, among which the meta‐isomer has the longest RTP lifetime (620.1 ms). Theoretical calculations reveal that the more efficient intersystem crossing, the slower radiative decay rate of the lowest triplet excitons, and stronger intermolecular hydrogen‐bonding interactions should be responsible for the superior RTP property of meta‐isomer. Furthermore, the tunable organic afterglow is readily realized via a triplet‐to‐singlet energy transfer process. More impressively, the meta and para isomers exhibit reversible photoactivated ultralong RTP properties after embedding into the rigid poly(methyl methacrylate) matrix. Finally, amorphous and flexible polymer films prepared from these positional isomers show potential applications in advanced anti‐counterfeiting and multilevel encryption through subtly combining ultralong RTP lifetime, tunable organic afterglow, and reversible photoactivation behavior.

Utilization of Tea Polyphenols as Color Developers in Reversible Thermochromic Dyes for Thermosensitive Color Change and Enhanced Functionality of Polyester Fabrics

Thermochromic textiles possess the capability to indicate ambient temperature through color changes, enabling real-time temperature monitoring and providing temperature warnings for body heat management. In this study, three thermochromic dyes—blue, red, and yellow—were synthesized using crystalline violet lactone (CVL), 6′-(diethylamino)-1′,3′-dimethyl-fluoran (DDF), and 3′,6′-dimethoxyfluoran (DOF) as leuco dyes, respectively, with biomass tea polyphenol serving as the color developer and tetradecanol as the phase change material. The chemical structures of these dyes were characterized using UV spectroscopy, infrared spectroscopy, Raman spectroscopy and 1H NMR. The thermochromic mechanisms were investigated, revealing that the binding bonds between the leuco dyes and the color developer broke and reorganized with temperature changes, imparting reversible thermochromic property. Polyester fabrics were dyed using an impregnation method to produce three reversible thermochromic fabrics in blue, red, and yellow. The structure and properties of these fabrics were analyzed, showing a significant increase in the UPF value from 26.3 to approximately 100, indicating enhanced UV resistance. Water contact angle measurements revealed that the contact angle of undyed polyester fabrics was 139°, while that of dyed polyester fabrics decreased by about 40°, indicating improved hydrophilicity. Additionally, the fabric inductive static tester showed that the static voltage half-life of dyed polyester fabric was less than 1 s, demonstrating a significant antistatic effect. Infrared thermal imaging results indicated that during the warming and cooling process, the thermochromic polyester fabric exhibited specific energy storage and insulation effects at 38 °C, close to the human body temperature. This study presented a novel approach to developing smart color-changing textiles using biomass-derived thermochromic dyes, offering diverse materials for personal thermal management, and intelligent insulation applications.

Robust conductive hydrogel advances self-powered intelligent sports monitoring and fair judging

Currently, combining multimodal perceptual ability with mechanical robustness poses a significant challenge for developing hydrogel-based flexible electronics. Herein, a robust conductive hydrogel was successfully synthesized by introducing cellulose nanocrystals (CNC) as nanofillers and lithium chloride (LiCl) as the conductive component into the copolymer network through a one-pot crosslinking procedure in a water-dimethyl sulfoxide binary solvent. Besides excellent stretchable, self-adhesive, anti-freezing, self-healing, and anti-swelling properties, tunable and reversible optical property was realized due to the polarity-induced microphase separation of the hydrophilic and hydrophobic group in the zwitterionic sulfobetaine chains, enabling cyclic information encryption and decryption. An all-weather wearable sensor array was thus developed for multi-modal sensing of various environmental stimuli, including mechanical, and thermal variations. Specifically, the intensity and spatial distribution of strain can be detected almost in real time within a broad strain range, thus realizing speech recognation, text-to-speech and human electrocardiogram signal acquisition and underwater non-contact sensing functions. Notably, the CPAMD-based triboelectric nanogenerator demonstrates impressive temperature tolerance (−40 °C and 60 °C), and remarkable material identification capability. A non-contact proximity sensing sensor and a foul detection system were thus developed by coupling the piezoresistive, triboelectric and capacitive sensing metrics to serve as an electronic referee for identifying foul in curling. This work provides a valuable reference toward combining excellent mechanical robustness with balanced electrical performance for tactile perception and intelligent sports monitoring.

Ti/Cr regulated and strategic Ce doped V-Ti-Cr-Mn-Fe high-entropy alloys with extraordinary reversible hydrogen storage properties at ambient temperature

High-entropy alloys (HEAs) are garnering widespread interest due to their exceptional hydrogen storage capabilities at ambient temperatures. Herein, a series of HEAs composed of V-Ti-Cr-Mn-Fe with varying Ti/Cr ratios has been synthesized via arc melting to serve as carrier materials for room-temperature hydrogen storage. Thanks to the composition of a large amount of body centered cubic (BCC) phase V32TixCr58-xMn5Fe5 exhibits excellent hydrogen storage performance, and the hydrogen absorption capacity of these HEAs escalates while the desorption capacity initially rises followed by a decline with an increase in the Ti/Cr ratio. Notably, the HEA with a Ti/Cr ratio of 1.0, namely V32Ti29Cr29Mn5Fe5, demonstrates exceptional performance by absorbing 3.55 wt% H2 within 60 min and rapidly releasing 2.16 wt% H2 within 5 min at 303 K. Further enhancement is achieved with the strategic doping of Ce in the V32Ti29Cr29Mn5Fe5, which leads to the removal of the Ti-rich phase and the incorporation of CeO2, significantly improves the activation performance, allowing the Ce-doped HEA to reach saturation in the 3rd hydrogen absorption cycle. Consequently, the hydrogen ab-/desorption capacities at ambient temperature are further augmented to 3.73 wt% and 2.26 wt%, respectively, and the enthalpies of hydrogen ab-/desorption are significantly reduced to −25.0 and 23.4 kJ/mol H2, marking a new benchmark for V-based HEAs. Dramatically, DFT calculations suggestes that the incorporation of Ce diminishes the structure energy of BCC phase structure for V32Ti29Cr29Mn5Fe4Ce1 as well as elongates the average distance of M−H from 1.955 Å to 1.969 Å, which corroborate the experimental results, offering profound insights into the underlying mechanisms of hydrogen storage within BCC-phase HEAs at ambient temperature.

Modification of BCC phase and the enhanced reversible hydrogen storage properties of Ti-V-Fe-Mn alloys with varied V/Fe ratios

Modification of BCC phase and the enhanced reversible hydrogen storage properties of Ti-V-Fe-Mn alloys with varied V/Fe ratios

Reversible Tuning Electrical Properties in Ferroelectric SnS with NH3 Adsorption and Desorption.

Two-dimensional (2D) ferroelectrics usually exhibit instability or a tendency toward degradation when exposed to the ambient atmosphere, and the mechanism behind this phenomenon remains unclear. To unravel this affection mechanism, we have undertaken an investigation utilizing NH3 and two-dimensional ferroelectric SnS. Herein, the adsorption and desorption of NH3 molecules can reversibly modulate the electrical properties of SnS, encompassing I-V curves and transfer curves. The response time for NH3 adsorption is approximately 1.12 s, which is much quicker than that observed in other two-dimensional materials. KPFM characterizations indicate that air molecules' adsorption alters the surface potentials of SiO2, SnS, metal electrodes, and contacts with minimal impact on the electrode contact surface potential. Upon the adsorption of NH3 molecules or air molecules, the hole concentration within the device decreases. These findings elucidate the adsorption mechanism of NH3 molecules on SnS, potentially fostering the advancement of rapid gas sensing applications utilizing two-dimensional ferroelectrics.

Preparation of natural adhesives with high-strength and low temperature fast-curing properties

The development of natural adhesives to substitute petroleum-based products is crucial for sustainable progress. However, the bond strength of most existing natural adhesives still falls short of that of commercially available adhesives and the curing process often demands prolonged high-temperature treatment. Herein, we prepared pure natural adhesives using gelatin (GE), tung oil (TO), and dopamine (DA) as the main raw materials. The shear strength of the adhesive to wood reached up to 6.35 MPa, a significant improvement over most natural wood adhesives reported. Additionally, the tensile strength of the adhesive to wood reached 10.50 MPa, which is comparable to commercially available neoprene-phenolic wood adhesives (9.99 MPa) and cyanoacrylate instant adhesives (9.48 MPa). In addition, the natural adhesive prepared by us exhibits fast curing performance at room temperature and can be fully cured in only 12 min, which is significantly better than the commercially available adhesive. The adhesives prepared in this study also possessed excellent reversible curing properties, antimicrobial properties, low toxicity, and degradability. These characteristics offer new insights for the advancement and dissemination of natural adhesives.

Main-Chain Azobenzene Poly(ether ester) Multiblock Copolymers for Strong and Tough Light-Driven Actuators.

The stimulus-responsive polymeric materials have attracted great research interest, especially those remotely manipulated materials with potential applications in actuators and soft robotics. Here we report a photoresponsive main-chain actuator based on azobenzene poly(ether ester) multiblock copolymer (mBCP) thermoplastic elastomers, (PTAD-b-PTMO-b-PTAD)n, which were synthesized by a cascade polycondensation-coupling ring-opening polymerization method using poly(tetramethylene oxide) (PTMO) and azobenzene-containing cyclic oligoesters (COTADs) as monomers. The thermal, mechanical, and microphase separation behaviors of mBCPs could be flexibly tuned by altering the ratios of soft-to-hard segments and block number (n). The oriented azobenzene mBCP fibers were prepared by melt spinning, showing reversible photoresponsive properties with remarkably high strength (∼1000 MPa) and high elongation at break comparable to spider silks. Fast photoinduced bending and contraction were successfully achieved in these fibers with high work and power densities and energy conversion efficiency, enabling it to lift up about 250 times of its own weight. Moreover, it can take out materials inside the tube by UV-light control. These fibers could be applied in light-driven actuators or telecontrolled robot arms.

Pressure control of tritiated hydrogen isotopologues in hermetically sealed vessels by non-evaporable getters for sub-Doppler-resolution spectroscopy

Small molecules serve as valuable benchmarks for testing quantum chemical theories. Ultra-high-resolution spectroscopy currently offers the capability of measuring molecular hydrogen energy levels with a relative accuracy on the order of 10-10. Expanding such investigations to encompass different isotopologues of molecular hydrogen has emerged as a promising avenue for examining mass-dependent contributions to the full description of molecular structure in the framework of relativistic quantum electrodynamics. However, the delicate nature of handling radioactive tritium in a high-resolution spectroscopy environment poses significant technological challenges, thereby limiting the extension of these studies to include T2, DT and HT isotopologues. In this work, we present the experimental setup of the very sensitive, Doppler-free technique of Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectroscopy (NICE-OHMS), used to measure rovibrational transitions in the HT molecule. The NICE-OHMS measurements were performed in a closed cavity system without connection to an actively pumped vacuum system. For this reason, a new method for tritium storage and pressure regulation within 0.05–1Pa based on a temperature-controlled mini-getter system is employed using less activity than the tritium exemption limit (1GBq). Non-Evaporable Getters of the type SAES St171 were used for this purpose exploiting their property that hydrogen is released upon heating, while other gases remain being pumped. Prior to the NICE-OHMS experiment, the reversible sorption properties of the getter for hydrogen isotopes were investigated. We show measurements of the equilibrium (hydrogen) pressure for all three pure isotopes and for a H2:HT:T2 mixture (with H:T = 1:1) as a function of temperature for a system of defined volume and amount of gas. For the read-out of the temperature, a method using the resistance of the getter in combination with a pyrometric calibration has been implemented. We discuss the experiences from practical use of the tritium getter and show results obtained with the NICE-OHMS setup leading to frequency calibration of near-infrared transitions in HT at an accuracy, surpassing previous studies by nearly three orders of magnitude.

M, NM-polynomials Based on Reverse, Reduced Reverse Degree and Neighborhood Degree Based Topological Indices with Applications to Bond Energy of Y-Junction Nanotubes.

In graph theory, M polynomials like the matching polynomial are very crucial in examining the matching structures within graphs, while NM polynomials extends this to analyze non-matching edges. These polynomials are important in many fields, including chemistry and network architecture. They support the derivation of topological indices for protein structure analysis, network communication optimization, and drug design in QSAR/QSPR investigations. The aim of this paper is to define novel M and NM polynomials for different topological indices and to derive their closed-form expressions, specifically for Y-junction nanotubes. These new polynomials and indices are employed to create a robust QSPR model to predict bond energy in Y-junction nanotubes, that provide high accuracy and reliability in the model's statistical performance. This paper introduces new forms of M and NM polynomials tailored to specific topological indices related to reverse and neighborhood reverse properties. We derive closed-form expressions for these indices in Y-junction nanotubes. Furthermore, we develop a QSPR model to predict bond energy in Y-junction nanotubes using the newly defined indices. We define novel M and NM polynomials for various topological indices and derive precise expressions for Y-junction nanotubes. Utilizing these indices, we construct a highly accurate QSPR model (R² = 0.999) for predicting bond energy in Y-junction nanotubes, confirming the validity of our polynomial definitions and indices. We have presented new M and NM polynomials for different topological indices and derive their expressions specifically for Y-junction nanotubes. With these newly defined indices, we have developed a highly precise QSPR model to predict bond energy, achieving an R² value of 0.999. This work underscores the effectiveness of our polynomial definitions and indices in predicting material properties.

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.

In-situ XRD study on phase transition kinetics of vanadium dioxide thin film

Vanadium dioxide (VO2) has great potentials to be used in energy-related fields due to its unique reversible thermochromic metal-insulating properties. In this paper, we used in-situ XRD technique to study the phase transition kinetics of VO2 thin films, which can change phase from monoclinic VO2 (M) to tetragonal rutile VO2 (R). The VO2 thin films were prepared by a simple solution-based sol-gel method followed by spin coating to achieve the nanoscale thickness on a quartz substrate. During heating, the critical phase transition of VO2 (M) occurred at 70 °C, which dropped to 45 °C during cooling. A martensite-like crystal phase transformation kinetic model was established based on the Koistinen and Marburger (KM) technique. The relative content of the two phases was quantitatively analyzed using the Rietveld method, and the transformation rate coefficient α was obtained as 0.20345 and 0.12585, for the heating process from VO2 (M) to VO2 (R) and the cooling process from VO2 (R) to VO2 (M), respectively. This research offers an effective tool for understanding the structural characteristics of thin film VO2, paving the way for its future design and applications towards energy-related fields such as in smart windows.

Perylene Bisimide-Functionalized Triphenylmethyl Radicals Showing High Stability and Reversible Electrochemical Redox Properties.

This study presents a series of triphenylmethyl monoradicals incorporating varying numbers of peripheral perylene bisimide (PBI) substituents (1PBI-TTM·, 2PBI-TTM· and 3PBI-TTM·). The incorporation of electron-withdrawing PBI substituents significantly enhances the stability of these carbon radicals, enabling them to display exceptional electrochemical redox reversibility. Notably, the electronic interplay between the PBI substituents and the central triphenylmethyl core facilitates unique and reversible multi-step redox reactions. Among the reported redicals, the tris-PBI functionalized radical (3PBI-TTM·) demonstrates the remarkable ability to accommodate up to seven electrons under negative potentials, forming high valence anions. This research pioneers the development of highly stable carbon radicals with superior electrochemical oxidation-reduction processes, presenting promising avenues for the advancement of electric energy storage technologies.