High Thermal Sensitivity Research Articles

Core–Shell Structured Nanofibers for Lithium Ion Battery Separator with Wide Shutdown Temperature Window and Stable Electrochemical Performance

Endowing separators in lithium ion batteries with highly sensitive shutdown function and good thermal stability is critical for the large-scale energy storage application of lithium ion batteries. In this work, a thermally induced shutdown separator with high thermal sensitivity and stability has been successfully fabricated via coaxial electrospinning of polyacrylonitrile (core) and poly(butylene succinate) (shell) (PAN@PBS). The separator is composed of core–shell structured and intersected nanofibers, which brings about the high porosity, excellent electrolyte wettability, and desirable electrolyte uptake. Meanwhile, the coaxial nanofibrous separator exhibits prompt shutdown response at 110 °C and remains structural integrity at 250 °C, indicating the coexisting characteristics of high thermal sensitivity and high thermal stability. Moreover, compared with the Celgard separator, the coaxial nanofibrous separator displays stable electrochemical properties in terms of higher ionic conductivity (2.1 mS cm–1) and superior cycling stability with capacity retention of 93.2% after 100 cycles at a 1 C rate and higher rate capability. Considering the high safety and good electrochemical performance, the as-prepared PAN@PBS nanofibrous membrane is a promising separator candidate for lithium ion batteries with enhanced safety.

Effective Ratiometric Luminescent Thermal Sensor by Cr3+‐Doped Mullite Bi2Al4O9 with Robust and Reliable Performances

AbstractThe design of effective optical systems featuring high thermal sensitivity able to discriminate ever smaller variations of temperature in noncontact mode is of critical importance to face the challenges brought by the modern‐day technological revolution. If from one hand, the ratiometric optical thermometers based on Boltzmann distribution are demonstrated to be characterized by a unique reliability, on the other hand, robust performances in different environments are highly desired for new applications such as in situ thermal sensing of catalytic reactions. Here, the crystal field experienced by Cr3+ in Bi2Al4O9 is investigated demonstrating the potential of this system as ratiometric self‐referencing thermal sensor being characterized by high relative sensitivity (1.24% K−1 at 290 K). The remarkable absolute sensitivity results in an exceptional low thermal resolution of ≈0.2 K, 15‐fold lower than for the conventional Nd3+‐based thermometers used in biological applications. The comparison of the performances among different systems evidences the potential of Cr3+‐based thermometers with thermal resolution even lower than the state of the art diamond. In addition, the pH dependence of the photoluminescence emission confirms a high stability also at extreme conditions of basic and acid environments and the aging effects are tested for one week.

High Thermal Sensitivity Performance of Ferroelectric Vanadium Oxide Hybrid Process in Thermal Imaging Monitoring

High Thermal Sensitivity Performance of Ferroelectric Vanadium Oxide Hybrid Process in Thermal Imaging Monitoring

Thermal hazard analysis of 1-((cyano-1-methylethyl) azo) formamide and effect of incompatible substances on its thermal decomposition

1-((cyano-1-methylethyl) azo) formamide (CABN) is an azo compound that exhibits high thermal sensitivity and self-reactivity. Because of incorrect operation, incompatible substances and other dangerous conditions, thermal explosion accidents may occur during the manufacturing, storage, and transportation of CABN. The pyrolysis characteristics of CABN and its mixture for various heating rates were assessed using differential scanning calorimetry. The results showed that incompatible substances increased the risk of CABN. Moreover, the thermal runaway of CABN under an adiabatic condition was studied using an adiabatic rate calorimeter to obtain the parameters under adiabatic condition. Based on the experimental data, the kinetic parameters of CABN and its mixtures were obtained. In addition, a thermal decomposition kinetic model of CABN was created using Thermal Safety Series. All experiments have shown that the conditions and parameters of CABN must be strictly controlled.

Epidermal electronics for respiration monitoring via thermo-sensitive measuring

The depth and rate of human respiration reveal important and diverse sets of physiological information for evaluating human health. Here, we introduce an ultrathin, skin-integrated respiration sensor based on the thermal convection effect. The device features a filamentary fractal design of the gold heating electrode, a mini sensor (0.6 mm × 0.3 mm × 0.23 mm) with high thermal sensitivity and an ultrasoft encapsulation package to enhance the overall flexibility and biaxial stretchability of the system. Adjusting the input power of the heating electrode, i.e., increasing the temperature difference between the thermal sensor and environment, can further improve the sensitivity of the respiration sensor. The real-time monitoring respiration sensor can competently distinguish various breathing patterns (sitting, frightening, sleeping, meditating, and gasping) through breath rate/depth of detection subjects. In addition, the respiration sensor can effectively capture, in real time, the respiration of a volunteer while exercising, resting, or sleeping for prolonged periods of time. The combination of advanced mechanics, high sensitivity, and good stability make this respiration sensor a great candidate for potential use in real-time monitoring of human health.

Stretchable and Heat‐Resistant Protein‐Based Electronic Skin for Human Thermoregulation

AbstractSilk protein is one of the a promising materials for on‐skin and implantable electronic devices due to its biodegradability and biocompatibility. However, its intrinsic brittleness as well as poor thermal stability limits its applications. In this work, robust and heat‐resistant silk fibroin composite membranes (SFCMs) are synthesized by mesoscopic doping of regenerated silk fibroin (SF) via the strong interactions between SF and polyurethane. Surprisingly, the obtained SFCMs can endure the tensile test (>200%) and thermal treatment (up to 160 °C). Attributed to these advantages, traditional micromachining techniques, such as inkjet printing, can be carried out to print flexible circuits on such protein substrate. Based on this, Ag nanofibers (NFs) and Pt NFs networks are successfully constructed on both sides of the SFCMs to function as heaters and temperature sensors, respectively. Furthermore, the integrated protein‐based electronic skin (PBES) exhibits high thermal stability and temperature sensitivity (0.205% °C−1). Heating and temperature distribution detection are realized by array‐type PBES, contributing to potential applications in dredging of the blood vessel for alleviating arthritis. This PBES is also inflammation‐free and air‐permeable so that it can directly be laminated onto human skin for long‐term thermal management.

Ferrimagnetic mPEG-b-PHEP copolymer micelles loaded with iron oxide nanocubes and emodin for enhanced magnetic hyperthermia-chemotherapy.

As a non-invasive therapeutic method without penetration-depth limitation, magnetic hyperthermia therapy (MHT) under alternating magnetic field (AMF) is a clinically promising thermal therapy. However, the poor heating conversion efficiency and lack of stimulus–response obstruct the clinical application of magnetofluid-mediated MHT. Here, we develop a ferrimagnetic polyethylene glycol-poly(2-hexoxy-2-oxo-1,3,2-dioxaphospholane) (mPEG-b-PHEP) copolymer micelle loaded with hydrophobic iron oxide nanocubes and emodin (denoted as EMM). Besides an enhanced magnetic resonance (MR) contrast ability (r2 = 271 mM−1 s−1) due to the high magnetization, the specific absorption rate (2518 W/g at 35 kA/m) and intrinsic loss power (6.5 nHm2/kg) of EMM are dozens of times higher than the clinically available iron oxide nanoagents (Feridex and Resovist), indicating the high heating conversion efficiency. Furthermore, this composite micelle with a flowable core exhibits a rapid response to magnetic hyperthermia, leading to an AMF-activated supersensitive drug release. With the high magnetic response, thermal sensitivity and magnetic targeting, this supersensitive ferrimagnetic nanocomposite realizes an above 70% tumor cell killing effect at an extremely low dosage (10 μg Fe/mL), and the tumors on mice are completely eliminated after the combined MHT–chemotherapy.

Thin-film heat-sensitive elements on the basis of semimetals for electromagnetic radiation receivers

The paper presents the generalized results of the authors’ work on the study of thin films of semimetals, which can be used in the development of universal electromagnetic radiation receivers. It is shown that thin-film materials based on semimetals have high thermal sensitivity, low intrinsic noise and an increased absorption coefficient of radiation in the millimeter region of the spectrum. Samples of bismuth films and bismuth–antimony films were obtained by vacuum thermal spraying. A study was made on the thermoelectric properties of bismuth–antimony thin films in the range from liquid helium temperature to room temperature in order to use these films as a bolometric type sensitive element in the range from infrared to radio frequency. A scheme and description of experimental installations for measuring current-voltage characteristics and determining the resistance of samples in the temperature range 1.4–400 K are presented. In the course of the study, the current-voltage characteristics and the temperature dependences of the resistance of film samples with a thickness of 80 and 20 nm were obtained. The characteristics of the manufactured prototype receiver were measured and used as a basis for estimating the possibility of developing bolometric-type receivers with increased NEP (Noise Equivalent Power). The NEP of the manufactured receivers at a frequency of 147 GHz was measured at room temperature and appeared to be ≈(0.3÷1)∙10 –9 Hz 1/2 . This NEP value can be improved by cooling the receiver to liquid nitrogen or helium temperatures.

Utilization of micronized recycled polyethylene waste to improve the hydrophobicity of asphalt surfaces

Super-Hydrophobic (SH) surfaces possessed low free energy and are highly resistant to wetting. These properties of SH surfaces made them suitable for engineering applications like waterproofing, anti-corrosion coatings, anti-icing finish etc. Asphalt binder that is widely adopted as civil engineering material for waterproofing application is only hydrophobic, not SH. In this study, recycled Low Density and High Density Poly-Ethylene (rLDPE & rHDPE) were employed to transform asphalt surface from hydrophobic to SH. Micronized rLDPE and rHDPE powders were obtained by grinding and sieving. The morphologies, thermal characteristics, and particles distributions of the various powders were analyzed using Scanning Electron Microscope (SEM), Differential Scanning Calorimetry (DSC); Thermogravimetric Analysis (TGA), and laser diffraction method respectively. The asphalt surfaces were modified by thermally fusing the micronized rLDPE and rHDPE at 100 °C for 15, 30, and 45 min curing durations. Roughness and Water Contact Angle (WCA) of the rLDPE and rHDPE treated asphalt surfaces were analyzed using 3D optical profilometer and sessile drop video contact angle system, respectively. The bonding at asphalt-rLDPE/rHDPE interfaces, and surface morphologies of the rLDPE and rHDPE asphalt surfaces were studied using SEM. Surface roughness decreases with increase in curing duration due to settling and thermal shrinkage of rLDPE/rHDPE particles. The WCA of the asphalt was increased by at least 35% for just 15 min curing duration. However, longer curing duration was found to yield a more resilient treated surface. The increase in WCA transformed the asphalt surfaces from hydrophobic to SH. Due to the elongated and fuzzy morphology of the rLDPE powder, in addition to its higher thermal sensitivity, it was able to form a better surface texture that facilitate higher WCA than the rHDPE. Statistical analysis of variance was conducted to assess the extent at which the micronized powder types and curing duration affect the surface roughness and WCA.

Rotary dryer for thermo sensitive products

To achieve the desired drying objectives in thermal sensitive products, such as medicinal plants, the process chosen should happen under minimally controlled conditions, such as, uniformity of temperature and air velocity, minimizing heat loss and with energy viability and efficiency. If possible, the process must occur using equipment with industrial implementation where the evaporation rate can be controlled. The intermittent drying process, which consist of cycles of exposure of the material to heated air (period of effective drying) and tempering (period of no exposure to heated air), is a great option to preserve the product’s quality during the drying process. We propose a new configuration of rotary dryer intended for intermittent drying; observing the configurations of widely applied rotary dryers, the relationship between angular velocity, period and frequency of rotation and laboratory experiments of manufacturing process in intermittent drying. The proposed dryer is efficient for the application of intermittent drying in products with high thermal sensitivity, such as medicinal plants. Making possible uniformity of temperature and air velocity distribution, minimizing heat loss and with energy viability and efficiency, guarantying the product quality.

Water-soluble poly(N-isopropylacrylamide) nanoparticles grafted to trivalent lanthanide complexes as highly sensitive ratiometric nanothermometers

A new water-soluble, luminescent ratiometric nanothermometer with a tunable temperature-responsive range, high thermal sensitivity and good repeatability was designed and synthesized by grafting lanthanide complexes to pNIPAM polymeric nanoparticles.

Colloidal (Gd0.98Nd0.02)2O3 nanothermometers operating in a cell culture medium within the first and second biological windows

Non-contact, self-referenced and near-infrared luminescent nanothermometers have been recognized as emerging tools in the fields of nanomedicine and nanotechnology due to their great capability of precise temperature readout at the nanoscale and real-time deep-tissue imaging. However, the development of multifunctional and biocompatible luminescent nanothermometers operating within the optically transparent biological windows with high thermal sensitivity (>2.0%/K) remains challenging. Here, we present (Gd0.98Nd0.02)2O3 nanothermometers operated effectively within the first and second biological windows upon continuous-wave laser diode excitation at 808 nm. Ratiometric thermometric parameters are defined by the relative changes in the emission intensities originating from the two Stark components of the 4F3/2 level (R2 and R1) to the 4I9/2 (900–1000 nm), 4I11/2 (1035–1155 nm) and 4I13/2 (1300–1450 nm) multiplets. The thermometric parameters are evaluated for colloidal samples in a cell culture medium and powder samples, and the highest thermal sensitivity (2.18%/K at 298 K) is attained for the former in the first biological window (both the excitation and emission in the 800–965 nm range). The repeatability and temperature uncertainty are 99% and 1.2 K, respectively. The nanothermometers are biocompatible with human MNT-1 melanoma and HaCaT cells for 24 h of exposure and nanoparticle concentration up to 0.400 mg/mL, showing their potential for applications in nanomedicine, e.g., intracellular imaging and temperature mapping.

Thermal preferences and effects of temperature on fitness parameters of an endemic Argentinean tarantula (Grammostola vachoni)

Mygalomorphs depend on thermal microhabitats for successful behavior, but their thermal biology is still poorly known. Grammostola vachoni Schiapelli and Gerschman, 1961 is an endemic tarantula from Argentina and it is listed as vulnerable in the IUCN Red List. However, little is known about its biology; therefore, we attempted to explore the thermal biology of juveniles and adult females of G. vachoni under laboratory conditions. We characterized the preferred temperatures, evaluated the relationship between temperature and locomotor performance, and calculated the thermal sensitivity. Individuals showed a peak temperature preference and spent 40% of the total time at 25–29 °C; we did not find any significant differences in temperature preference between juveniles and females. We found that locomotor performance is strongly affected by high temperatures. Different sprint speeds of juveniles and females were found at 5, 35, and 40 °C. The highest thermal sensitivity was recorded in the lowest temperature range and thermal sensitivity was lowest in the highest temperature ranges. Our results are relevant in the context of climate change, because thermal parameters constitute a useful tool to explore some possible effects of this change on body temperature and thus the physiological performance and vulnerability of ectotherms like G. vachoni.

Triplet-State Position and Crystal-Field Tuning in Opto-Magnetic Lanthanide Complexes: Two Sides of the Same Coin.

Lanthanide-complex-based luminescence thermometry and single-molecule magnetism are two effervescent fields of research, owing to the great promise they hold from an application standpoint. The high thermal sensitivity achievable, their contactless nature, along with sub-micrometric spatial resolution make these luminescent thermometers appealing for accurate temperature probing in miniaturised electronics. To that end, single-molecule magnets (SMMs) are expected to revolutionise the field of spintronics, thanks to the improvements made in terms of their working temperature-now surpassing that of liquid nitrogen-and manipulation of their spin state. Hence, the combination of such opto-magnetic properties in a single molecule is desirable in the aim of overcoming, among others, addressability issues. Yet, improvements must be made through design strategies for the realisation of the aforementioned goal. Moving forward from these considerations, we present a thorough investigation of the effect that changes in the ligand scaffold of a family of terbium complexes have on their performance as luminescent thermometers and SMMs. In particular, an increased number of electron-withdrawing groups yields modifications of the metal coordination environment and a lowering of the triplet state of the ligands. These effects are tightly intertwined, thus, resulting in concomitant variations of the SMM and the luminescence thermometry behaviour of the complexes. Supported by ab initio calculations, we can rationally interpret the observed trends and provide solid foundations for the development of opto-magnetic lanthanide complexes.

Design and Fabrication of Silk Templated Electronic Yarns and Applications in Multifunctional Textiles

Summary E-textiles are of interest in a variety of fields, such as wearable electronics and real-time healthcare monitoring. Critical challenges remain, related to design and fabrication techniques to meet the varied requirements for e-textiles. As an ancient and incomparable textile fiber, natural silk fibers can be considered to address these issues. However, processing challenges have thus far precluded the realization of electrically conducting natural silks. Here, we report a scalable dip-coating strategy to construct conductive silk fibers (CSFs). Natural silk fibers were functionalized by a tailor-made carbon nanotube (CNT) paint, which selectively etches the surface of the silk fibers without destroying the internal structure of the fibers. The CSFs maintained the properties of both the silks and CNTs, with high mechanical performance, super-hydrophobicity, solvent resistance, and thermal sensitivity. The CSFs can be automatically woven into fabrics, resulting in textiles sensitive to surrounding physical stimuli, including force, strain, temperature, and solvents.

1,2,4-Oxadiazole-Bridged Polynitropyrazole Energetic Materials with Enhanced Thermal Stability and Low Sensitivity.

A family of mono or di(1,2,4-oxadiazole)-bridged polynitropyrazole derivatives with C-nitro/N-nitro functionalities is reported. All compounds were fully characterized by IR, NMR (1 H, 13 C), elemental analysis and differential scanning calorimetry (DSC). The solid-state structure features were further investigated with X-ray diffraction. Of these, compounds 3,5-bis(3,4-dinitro-1H-pyrazol-5-yl)-1,2,4-oxadiazole (3 a) and 5,5'-bis(3,4-dinitro-1H-pyrazol-5-yl)-3,3'-bi(1,2,4-oxadiazole) (3 b) possess high thermal stability (3 a: Tdec =274 °C; 3 b: Tdec =272 °C), sensitivity (IS >30 J, FS >360 N) and comparable detonation properties (3 a: Dv =8741 m s-1 , P=34.0 GPa; 3 b: Dv =8685 m s-1 , P=33.4 Gpa) to RDX. In addition, 3,5-bis(4-nitro-1H-pyrazol-3-yl)-1,2,4-oxadiazole (4 a) and 5,5'-bis(4-nitro-1H-pyrazol-3-yl)-3,3'-bi(1,2,4-oxadiazole) (4 b) have high decomposition temperature (4 a: Tdec =314 °C; 4 b: Tdec =317 °C), low sensitivity (IS >40 J; FS>360 N) and superior detonation performances (4 a: Dv =8027 m s-1 , P=26.4 GPa; 4 b: Dv =7991 m s-1 , P=25.2 Gpa) than conventional heat-resistant explosive hexanitrostilbene (HNS: Tdec =318 °C; IS=5 J; FS=240 N; Dv =7612 m s-1 , P=24.3 GPa), thus suggesting their potential application as heat-resistant explosives.

Tunable Hybrid Phononic Crystal Lens Using Thermo-Acoustic Polymers.

Solid phononic crystal (PnC) lenses were made active on infiltration with thermosensitive polymers to produce a thermoactuated hybrid solid lens with variable focusing. Acoustic lenses, both solid state and PnCbased, are passive elements with a fixed focal length. Their focal characteristics are functions of the lens structure or the arrangement of the PnC unit cell. Dispersion effects, liquid-filled membranes, and phase delay in a multi-element emitter have been used for variable focusing. The high thermal, electric, and electromagnetic sensitivity of the elastic properties of poly(vinyl alcohol) (PVA) poly(N-isopropylacrylamide) (PNIPAm)-based hydrogels enable them to operate as tunable solids. However, these solids do not have strong enough contrast with water or well-controlled shape parameters to function as standalone lenses. Here, a tunable hybrid solid ultrasonic lens is realized by combining a PnC lens with PVA-PNIPAm thermoacoustic hydrogel to modify the transmission and dispersion properties of transient acoustic waves. Variable focusing is demonstrated from 40 to 50 mm using the anomalous thermosensitivity of the elasticity and speed of sound of the hydrogel.

TmDOTP: An NMR-based thermometer for magic angle spinning NMR experiments.

Solid state NMR is a powerful tool to probe membrane protein structure and dynamics in native lipid membranes. Sample heating during solid state NMR experiments can be caused by magic angle spinning and radio frequency irradiation such heating produces uncertainties in the sample temperature and temperature distribution, which can in turn lead to line broadening and sample deterioration. To measure sample temperatures in real time and to quantify thermal gradients and their dependence on radio frequency irradiation or spinning frequency, we use the chemical shift thermometer TmDOTP, a lanthanide complex. The H6 TmDOTP proton NMR peak has a large chemical shift (-176.3 ppm at 275 K) and it is well resolved from the protein and lipid proton spectrum. Compared to other NMR thermometers (e.g., the proton NMR signal of water), the proton spectrum of TmDOTP, particularly the H6 proton line, exhibits very high thermal sensitivity and resolution. In MAS studies of proteoliposomes we identify two populations of TmDOTP with differing temperatures and dependency on the radio frequency irradiation power. We interpret these populations as arising from the supernatant and the pellet, which is sedimented during sample spinning. In this study, we demonstrate that TmDOTP is an excellent internal standard for monitoring real-time temperatures of biopolymers without changing their properties or obscuring their spectra. Real time temperature calibration is expected to be important for the interpretation of dynamics and other properties of biopolymers.

Optical nanothermometry under multiphonon assisted anti-Stokes excitation operating in the biological windows

In this work, we report a potential nanothermometer with high thermal sensitivity based on sodium niobate (NaNbO3) nanocrystals doped and co-doped with Tm3+ and Tm3+/Yb3+, respectively, synthesized by the Pechini (sol–gel) method. Under anti-Stokes excitation (1064 nm) it was investigated the fluorescence intensity ratio (FIR=I700nm/I660nm) of the 700 nm (3F2,3 → 3H6) and 660 nm (1G4 → 3F4) emissions, which are within the first biological window, as a function of temperature in the 300–493 K range. Relative thermal sensitivities constant with the temperature were obtained, with values of 1.60% K−1 and 1.86% K−1 for NaNbO3:1%Tm3+ and NaNbO3:1%Tm3+/1%Yb3+ samples, respectively, which is the highest value in the literature for Tm3+/Yb3+ co-doped system under 1064 nm excitation. The importance of the anti-Stokes excitation relies on the fact that emissions (up and downconversion) in general increase with the temperature, making possible obtaining fluorescence and thermal images with better resolutions. Additionally, as both excitation and emission are within the biological windows, these nanoparticles might be useful for biological applications.

Decomposition prevention through thermal sensitivity of hydrate formations around wellbore

The traditional drilling engineering research on wellbore stability of hydrate formation neglects the interactions between heat transfer and mass transfer, a new multi-field coupling model is established to study the effects, and this model considers hydrate kinetic decomposition rate in different salinities, two-phase flows and heat transfer in pores. The calculation results show most of engineering parameters affects hydrate decomposition through high thermal sensitivity of hydrate formations: The direction and value of seepage will change the temperature field and the position of hydrate dissociation front. High bottomhole pressure will bring in the radial seepage, increasing formation temperature and exacerbating hydrate decomposition. The latent heat of hydrate dissociation reduces temperature growth in the entire formation, inhibits the decomposition front advancement and decreases the decomposition rate. Reducing the bottomhole temperature can get an incremental margin for wellbore stability. High salinity in drilling fluid will provide negative impact under high bottomhole pressure and high permeability. These results show the protection of hydrate formations should avoid increasing the density of drilling fluid and focus on cooling drilling fluid and reducing drilling time.