Phase Transition Temperature Research Articles

Renewable synthesis of MoO3 nanosheets via low temperature phase transition for supercapacitor application

2D transition metal oxides have created revolution in the field of supercapacitors due to their fabulous electrochemical performance and stability. Molybdenum trioxides (MoO3) are one of the most prominent solid-state materials employed in energy storage applications. In this present work, we report a non-laborious physical vapor deposition (PVD) and ultrasonic extraction (USE) followed by vacuum assisted solvothermal treatment (VST) route (DEST), to produce 2D MoO3 nanosheets, without any complex equipment requirements. Phase transition in MoO3 is often achieved at very high temperatures by other reported works. But our well-thought-out, robust approach led to a phase transition from one phase to another phase, for e.g., hexagonal (h-MoO3) to orthorhombic (α-MoO3) structure at very low temperature (90 °C), using a green solvent (H2O) and renewable energy. This was achieved by implementing the concept of oxygen vacancy defects and solvolysis. The synthesized 2D nanomaterials were investigated for electrochemical performance as supercapacitor electrode materials. The α-MoO3 electrode material has shown supreme capacitance (256 Fg−1) than its counterpart h-MoO3 and mixed phases (h and α) of MoO3 (< 50 Fg−1). Thus, this work opens up a new possibility to synthesize electrocapacitive 2D MoO3 nanosheets in an eco-friendly and energy efficient way; hence can contribute in renewable circular economy.

The Role of α−β Quartz Transition in Fluid Storage in Crust From the Evidence of Electrical Conductivity

AbstractAqueous fluids are extensively present in the middle to lower crust, as revealed by seismic and magnetotelluric soundings. The α−β quartz phase transition significantly affects many physical properties and leads to substantial microcracks that can provide pathways for the migration of crustal fluids. A systematic investigation of macroscopic physical properties and microstructure of quartz is crucial to elucidate their correlation. In the present study, the effects of water content, trace elements, orientations, and phase transition on the electrical conductivity of quartz were thoroughly evaluated at 400−900°C and 1 GPa. Individual annealing experiments were simultaneously conducted on quartz single crystals at different peak temperatures and 1 GPa to investigate the evolution and spatial distribution of microcracks using X‐ray microtomography (CT) and backscattered electron imaging. We found that trace element content and orientations, rather than H2O, are the dominant factors controlling the conductivity of quartz. The distinct changes in conductivity of single crystals at around α−β phase transition temperature are attributed to the transformation of microcracks from isolated to interconnected networks, as confirmed by two‐dimensional (2‐D) and three‐dimensional (3‐D) microstructure images. Based on the variation in electrical conductivity and microstructure across the transition, it thus is proposed that the intragranular microcracks caused by quartz phase transition can serve as fluid or melt pathways within highly conductive zones present in the middle to lower crust, while α‐quartz acts as an impermeable cap.

Low temperature phase transitions in the visible and near-infrared (VNIR) reflectance spectra of (NH4)2HPO4 and (NH4)HSO4 salts

The detection of ammonium bearing crystalline solids in salt-water systems on icy bodies and solar system bodies could provide information about the ascent of these salts from a deep reservoir within the hydrosphere. Due to their chemical-physical properties, NH4+ compounds play a key role both in the internal dynamics of celestial bodies and in the potential habitability of ocean worlds. In this work we analysed the reflectance spectra of two synthetic NH4+ salts: ammonium hydrogen phosphate (NH4)2HPO4 and ammonium hydrogen sulphate (NH4)HSO4 in the 1–4.2 μm spectral range at low temperature, between 110 and 290 K. For (NH4)2HPO4 we also examined the effect of three different grain sizes (150–125 μm; 125–80 μm; 80–32 μm). The collected reflectance spectra show absorption features related to NH4+ group overtone and combination modes in the 1–2.5 μm range. In particular, the bands located at ∼1.09 μm (3ν3), ∼1.30 μm (2ν3 + ν4), ∼1.58 μm (2ν3), ∼2.02 μm (ν2 + v3) and ∼ 2.2 μm (v3 + v4) could be useful to discriminate these salts. The low temperature spectra, compared to those at ambient temperature, reveal finer structures, displaying sharper and narrower absorption bands. The selected NH4+-bearing salts are subjected to reversible low temperature phase transitions, which are revealed in the spectra by a progressive growth and shift of the bands toward shorter wavelengths with a drastic change of their depth. We performed laboratory measurements of ammonium (NH4+) compounds to address the limited data available expanding the existing database. The collected cryogenic spectra can be directly compared with remote sensing data from planetary missions of the upcoming decade such as NASA's Europa Clipper, and ESA's JUICE and the newly launched James Webb Space Telescope expanding the existing database of ammonium compounds at cryogenic temperature.

Thermal properties and microstructure of Al–Sn alloys

The Al–Sn alloys feature excellent wear and corrosion resistance, along with good mechanical properties. They are mostly used as bearing materials. However, the application of these alloys as phase change materials (PCMs) for thermal energy storage (TES) has recently been suggested. To assess the adequacy of these alloys in a given area, a detailed evaluation of their thermal properties is required. In the present study, Al–Sn alloys with 11.7, 22.4, 32.8, 41.1, and 53.4 at.% Sn were produced by melting of pure metals. The melt was continuously stirred to avoid segregation, after which casting was carried out in a stainless steel mold. The obtained ingots had a homogeneous microstructure without the appearance of cracks and pores. The thermal diffusivities of the solid Al–Sn alloys in the temperature interval 25–150 °C were measured using the light flash method. The densities at room temperature were measured by the Archimedes method, and the specific heat capacities at different temperatures were calculated using the calculation of phase diagrams (CALPHAD) method. Then the thermal conductivities for studied Al–Sn alloys were obtained by the specific conversion equation. The phase transition temperatures and related heat effects were studied using differential scanning calorimetry (DSC). Variations of thermal conductivity with composition and temperature were determined as well as variation of latent heat of fusion with alloy composition. Moreover, the microstructures and phase compositions of the alloys were examined using scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS). The present research results provide important information on the thermal properties and microstructure of the Al–Sn alloys for designing new PCM for thermal energy storage.

Size and surface-dependent phase transition temperature in Cu2Se nanobridges

The critical phase transition temperature (Tc) of Cu2Se thermoelectric nanomaterials has been a focal point of extensive research, yet the quantification of surface energy on Tc is frequently ignored. In this paper, we systematically investigate the impact of both the width/thickness and surface configuration of Cu2Se nanobridges (NBs) on Tc. We find that the Tc decreases with size reduction, which becomes particularly accelerated when the size decreases to a few nanometers. Additionally, the NBs with higher energy surfaces exhibit lower Tc. Then we propose an optimized thermodynamic model to quantify the combined effect of size and surface energy on Tc in Cu2Se NBs, which provides an approach to predict Tc in Cu2Se and other thermoelectric nanomaterials. Our study facilitates the understanding of the dependence of Tc on size and surface in Cu2Se, with an eye towards the stable room temperature thermoelectric applications of Cu2Se nanomaterials.

Fabrication of acorn-shaped Janus C-SiO2 carrier and their application in DOX release

Asymmetric nanocarriers with different functions can achieve synergistic effect in cancer treatment. In this study, asymmetric carbon-silica (C-SiO2) carriers were prepared for drug delivery and combining therapy. The C-SiO2 carriers presented acorn-like structure with dendritic mesoporous silica hat and carbon body. The carbon body render the carriers photothermal effect. The prepared C-SiO2 carriers with size around 130 nm have improving cell uptake efficiency, and excellent biocompatibility. After loading doxorubicin hydrochloride (DOX), menthol (LM) was used to seal the loaded drug (DOX@C-SiO2-LM). LM coating can melt above the phase transition temperature, leading to the release of loaded cargo. The DOX@C-SiO2-LM displayed temperature/NIR-triggered drug release.

Localized delivery of Roxadustat via cubosomes-based thermosensitive in-situ hydrogel enhances diabetic wound healing by stabilizing HIF-1α in rats

Chronic non-healing wounds are a major complication among diabetic patients, significantly affecting their quality of life. The dysfunction of HIF-1, a crucial regulator of wound healing, contributes to impaired wound repair in diabetes. Roxadustat (ROX), an HIF-1α stabilizer, has emerged as a promising therapeutic candidate for addressing chronic wounds. Accordingly, a few studies have investigated the systemic administration of ROX for wound healing. However, concerns have arisen about potential side effects. Our study aimed to address these limitations by developing a localized delivery approach using ROX-loaded cubosomes (ROX-CUs) incorporated into a thermosensitive hydrogel. ROX-CUs were prepared and evaluated for particle size (125.6 ± 3.11 nm), zeta potential (−26.60 ± 2.08 mV), and entrapment efficiency (94.23 ± 2.93 %). ROX-CUs were then integrated into a poloxamer-based thermosensitive hydrogel with varying ratios of poloxamers 188 and 407. The selected formulation (F13) showed a phase transition temperature of 36.5 ± 0.4 °C and a drug content of 97.80 ± 1.60 %. In vitro drug release studies demonstrated a biphasic release for F13: an initial burst after 3 h (15.25 %) followed by sustained release up to 48 h (52.13 %), offering sustained release advantages. In vivo studies on diabetic rats revealed that F13 significantly accelerated wound closure (93 % reduction), with enhanced tissue characteristics, including neovascularization and increased collagen deposition. Additionally, F13 upregulated the HIF-1α and other tissue remodeling factors, creating an optimal environment for tissue repair. Consequently, ROX-CUs incorporated into a thermosensitive hydrogel hold significant promise as a novel therapeutic strategy for promoting wound healing in clinical settings.

Resistance behavior of Sb7Se3 thin films based on flexible mica substrate.

In this paper, we explored the resistivity behavior of Sb7Se3 thin films on flexible mica. The films maintained their resistance characteristics through various thicknesses and bending cycles. With increasing bends, resistivity and phase transition temperature of both amorphous and crystalline states rose, while the resistance drift coefficient gradually increased. Raman and near infrared experiments confirmed the internal structural changes and bandgap enhancement after bending. Transmission electron microscopy showed enhanced crystallization and uniform element distribution after annealing. Atomic force microscopy observed cracks, explaining the property changes. Additionally, we developed a flexible Sb7Se3 thin-film resistive device with swift reversibility (∼10ns) regardless of bending, opening new avenues for flexible information storage.

The defects and compressive behavior of NiTi alloy fabricated by laser powder bed fusion under a wide process space

A wide process space with laser power (P) of 50 ～ 400 W and scanning speed (s) of 50 ～ 2400 mm/s with the energy density (ED) range of 93–556 J/mm3 has been employed to fabricate NiTi alloy using laser powder bed fusion (LPBF). The optimal process window for near-full dense materials free of geometrical and metallurgical defects was determined. The characteristics of microstructures and compressive behaviors were comprehensively investigated. The results have shown that the process combinations of “high P + low s” and “high P + high s” are prone to bulging and warping defects due to rapid heating and cooling, respectively. A combination of “low P + low s” produces a relatively shallow melt pool without keyhole formation even at ED as high as 556 J/mm3. The austenite-martensite phase transition temperature (TTs) variations of ～80℃ were obtained with the process window free of porosity. The pre-existing martensite lath probably formed by plastic distortion (bulging) was responsible for the lowest critical stress of induced martensite (σSIM). The texture and nano-sized NiTi2/Ni2Ti4Ox precipitates also contribute to the variation of σSIM and residual strain among the samples with the same level of TTs upon compressive loading.

Thermal Performance Improvement of Composite Phase-Change Storage Material of Octanoic Acid–Tetradecanol by Modified Expanded Graphite

Phase-change cold storage technology is recommended as a solution for energy conservation and carbon neutrality in air conditioning systems of buildings. This study focuses on the development of binary composite phase-change materials comprising octanoic acid–tetradecanol (OA-TD). To enhance its thermal conductivity, expanded graphite (EG) was employed as an additive carrier, and the surface modification of EG particles using hexadecyltrimethoxysilane (HDTMOS) was attempted to make up for the instability and further to improve the performance of OA-TD/EG CPCMs. The OA-TD/EG-HDTMOS CPCMs were synthesized by EG mixed with EG-HDTMOS at a 1:1 mass ratio. The thermal performance and stability of the OA-TD/EG-HDTMOS CPCMs were thoroughly evaluated by multi-cycle melting–solidification and thermal conductivity measurements. The results revealed that the OA-TD mixture, when at a mass ratio of 77:23, exhibited a phase-transition temperature of 11.4 °C and a latent heat ranging from 150 to 155 J/g. Then, the OA-TD/EG-HDTMOS composite material, at a 12:1 mass ratio of OA-TD to EG-HDTMOS, solidified and melted at temperatures of 9.2 °C and 11.2 °C, with a latent heat ranging from 138 to 143 J/g, and significantly improved the thermal conductivity to 0.7 W/(m·K), representing a remarkable 133% increase compared to that of OA-TD alone. Even after undergoing 100 melting–solidification cycles, the OA-TD/EG-HDTMOS maintained superior phase-change thermal performance and stability, making it suitable for cold storage and energy conservation in air conditioning.

Discrepancy evaluation in mechanics and corrosion resistance of reactive plasma sprayed TiN coatings fabricated under different heat treatment

Ceramic coatings have positive feedback to annealing treatment, but improper annealing treatment can also bring disastrous consequences. In this article, a thick TiN coating without a bonding layer was prepared by reactive plasma spraying technology and then subjected to heat treatment at three different temperatures in atmospheric and argon atmospheres. By exploring the hardness, modulus, and corrosion resistance of the coatings, combined with analysis of microstructure, phase composition, and interatomic bonding conditions, it was found that the TiN coating exhibited the lowest porosity after atmospheric heat treated at 500 °C. Meanwhile, it also showed the highest hardness, modulus, and optimal corrosion resistance. After heat treated at 650 °C in the atmosphere, the protective performance of the coating was decreased, but it was still far superior to the as-sprayed coating. The coating after heat treated in the argon atmosphere did not achieve ideal performance. The coating heat treated at 650 °C even exhibited inferior comprehensive performance to the as-sprayed coating. Therefore, it was summarized that the atmospheric environments and the temperature above the phase transition temperature were suitable for obtaining the optimal TiN coating.

H-Bonds Enhanced Natural Polyphenols Bined Polysaccharide/Gelatin Composites with Controlled Photothermal Stimulation Phase Transition for Wound Care.

Severe open wounds should be closed immediately and regularly undergo re-examination and debridement. Therefore, dressings should effectively cover the wound, creating a moist environment for healing while meeting mechanical requirements for daily movement and adaptability. Herein, a low-cost and easy-to-prepare plant polysaccharide hydrogel was reported. The Mesona chinensis Benth polysaccharide strengthened the hydrogel network by hydrogen bonding and changed the phase transition temperature, but retained the thermal response characteristics of the hydrogel. By adjusting the polysaccharide concentration, MepGel(1) can be prepared to remain stable as a semisolid at body temperature and transform into a shear-thinning semifluid state when appropriately heated. The composite hydrogel could be easily shaped, effectively closing wounds of different shapes, while maintaining excellent mechanical properties. Importantly, this composite hydrogel had a near-infrared photothermal effect resulting in excellent antibacterial effect and collided with its own thermal response producing functions conducive to wound care, like accelerating the self-healing of the dressing, achieving re-adhesion, and further covering the wound. Furthermore, the hydrogel had excellent biocompatibility, enhancing immunity and promoting healing of bacterial-infected wounds. The low cost and rich functionality demonstrated by MepGel had the potential to face the enormous challenges and economic burden of clinical wound healing.

Avoided Quantum Tricritical Point and Emergence of a Canted Magnetic Phase in LaCr_{1-x}Fe_{x}Sb_{3}.

New phases or new phenomena are often observed near-zero temperature phase transitions. These new effects represent nature's way of avoiding quantum critical phase transitions. Here, we look at the quantum tricritical point (QTCP), the special case where two transitions are driven to zero temperature at the same time. Unlike the case of quantum critical points, the avoidance of quantum tricritical points has yet to be demonstrated. Using chemical substitution and a magnetic field, we drive LaCrSb_{3} toward a quantum tricritical point. For the first time near a QTCP, we observe the emergence of a new magnetic phase and the avoidance of the QTCP via a first order phase transition.

Continuous-Flow Synthesis of Zn1-xMnxS Nanoparticles at Ambient Conditions.

With its large direct band gap and good chemical stability, ZnS is suitable for many applications, including light-emitting diodes, panel displays, and photodetection. Here, nanoparticles of ZnS are synthesized phase pure under ambient conditions by precipitation in a simple and scalable continuous-flow reactor. Furthermore, different degrees of Zn substitution with Mn have been investigated, Zn1-xMnxS, with x = 0.05, 0.19, and 0.25 according to X-ray fluorescence measurements. The products are analyzed with multitemperature synchrotron powder X-ray diffraction (PXRD) and X-ray total scattering. The analysis reveals phase-pure synthesis products with the sphalerite structure and crystallite sizes in the range of 3.8-4.7 nm in agreement with scanning transmission electron microscopy. Only Zn0.75Mn0.25S shows traces of Mn3O4, indicating that x = 0.25 is above the substitution limit as the impurity appears. Substitution of Zn with Mn in the nanoparticles is confirmed by energy-dispersive X-ray spectroscopy, as well as an observed decrease in the band gap, decrease in the sphalerite-to-wurtzite phase transition temperature, and increase in the unit cell dimensions with increasing Mn content. Based on the modeling of the PXRD Rietveld refined atomic displacement parameters, the Debye temperature for ZnS and Zn0.95Mn0.05S is determined to be 322 ± 13 and 394 ± 22 K, respectively.

Corrections of Electron–Phonon Coupling for Second‐Order Structural Phase Transitions

Structural phase transitions are accompanied by a movement of one nucleus (or a few) in the crystallographic unit cell. If the nucleus movement is continuous, a second‐order phase transition without latent heat results, whereas an abrupt nucleus displacement indicates a first‐order phase transition with accompanying latent heat. Herein, a Hamiltonian including electron–phonon coupling (EPC) as proposed by Kristoffel and Konsel is taken. Contrary to their treatment, both the kinetic energy of the nucleus and its position are treated. The interaction of the many‐electron system with the single nucleus is taken into account by the Born–Oppenheimer approximation and perturbative expressions for the free energies are derived. The nuclei corrections due to the entangled electrons are found to be minor, but highlight the importance of the symmetry breaking at low temperature. Furthermore the free energy for a canonical ensemble is computed, whereas Kristoffel and Konsel use a grand canonical ensemble, which allows to derive more stringent bounds on the free energy. For the zero‐order nucleus correction, the shift of the phase transition temperature by evaluating the free energy is deduced.

Lattice Softening and Band Convergence in GeTe-Based Alloys for High Thermoelectric Performance.

GeTe-based alloys have been studied as promising TE materials in the midtemperature range as a lead-free alternate to PbTe due to their nontoxicity. Our previous study on GeTe1-xIx revealed that I-doping increases lattice anharmonicity and decreases the structural phase transition temperature, consequently enhancing the thermoelectric performance. Our current work elucidates the synergistic interplay between band convergence and lattice softening, resulting in an enhanced thermoelectric performance for Ge1-ySbyTe0.9I0.1 (y = 0.10, 0.12, 0.14, and 0.16). Sb doping in GeTe0.9I0.1 serves a double role: first, it leads to lattice softening, thereby reducing lattice thermal conductivity; second, it promotes a band convergence, thus a higher valley degeneracy. The presence of lattice softening is corroborated by an increase in the internal strain ratio observed in X-ray diffraction patterns. Doping also introduces phonon scattering centers, further diminishing lattice thermal conductivity. Additionally, variations in the electronic band structure are indicated by an increase in density of state effective mass and a decrease in carrier mobility with Sb concentration. Besides, Sb doping optimizes the carrier concentration efficiently. Through a two-band modeling and electronic band structure calculations, the valence band convergence due to Sb doping can be confirmed. Specifically, the energy difference between valence bands progressively narrows upon Sb doping in Ge1-ySbyTe0.9I0.1 (y = 0, 0.02, 0.05, 0.10, 0.12, 0.14, and 0.16). As a culmination of these effects, we have achieved a significant enhancement in zT for Ge1-ySbyTe0.9I0.1 (y = 0.10, 0.12, 0.14, and 0.16) across the entire range of measured temperatures. Notably, the sample with y = 0.12 exhibits the highest zT value of 1.70 at 723 K.

Effect of Process Parameters on Superelasticity of LPBF Ni-Rich Ni51.3Ti48.7 Shape Memory Alloy

Laser powder bed fusion (LPBF) presents both opportunities and challenges with regard to the customisation of NiTi alloy properties. This paper presents a systematic study of the influence of process parameters on the superelasticity of LPBF Ni-rich Ni51.3Ti48.7 shape memory alloy. The findings demonstrate that NiTi alloys produced through disparate process parameters exhibit disparate phase transformation behaviours and microstructures, which in turn result in varying degrees of superelasticity. At an energy density of 166.7 to 233.3 J/mm3, LPBFed Ni-rich Ni51.3Ti48.7 is predominantly in the martensite phase at room temperature due to the high phase transition temperature caused by a large amount of Ni evaporation loss, and exhibits almost no superelasticity. At an energy density of 66.7 to 116.7 J/mm3, LPBFed Ni-rich Ni51.3Ti48.7 has less Ni evaporation loss and lower phase transition temperature. It is primarily austenite phase at room temperature, and contains nano-precipitated phases internally, thereby exhibiting excellent superelasticity. The recovery rate is in excess of 5.5% at the initial compression (up to 5.7%) and in excess of 5.0% following ten cycles (up to 5.3%). Furthermore, the lower the energy density, the smaller the stress–strain hysteresis of LPBFed Ni-rich Ni51.3Ti48.7, with a variation range of 1.8–3.9 mJ/mm3.

Simulation of Corner Solidification in a Cavity Using the Lattice Boltzmann Method

This study investigates corner solidification in a closed cavity in which the left and bottom walls are kept at a temperature lower than its initial temperature. The liquid material in the cavity initially lies at its phase transition temperature and, due to cold boundary conditions at the left–bottom walls, solidification starts. The simulation of corner solidification was performed using a kinetic-based lattice Boltzmann method (LBM), and the tracking of the solid–liquid interface was captured through the evaluation of time. The present investigation addresses the effect of natural convection over conduction across a wide range of higher Rayleigh numbers, from 106 to 108. The total-enthalpy-based lattice Boltzmann method (ELBM) was used to observe the thermal profiles in the entire cavity with a two-phase interface. The isotherms reveal the relative dominance of natural convection over conduction, and the pattern of interface reveals the effective growth of the solidified layer in the cavity. To quantify the uniformity of cooling, a coefficient of variation (COV) for the thermal field was calculated in the effective solidified zone at a wide range of Ra. The results show that the value of COV increases with Ra and reduces with time. The thermal instability in the flow field is also quantified through FFT analyses.

Growth of Single Crystals of (K1-xNax)NbO3 by the Self-Flux Method and Characterization of Their Phase Transitions.

In this study, single crystals of (K1-xNax)NbO3 are grown by the self-flux crystal growth method and their phase transitions are studied using a combination of Raman scattering and impedance spectroscopy. X-ray diffraction shows that single crystals have a perovskite structure with monoclinic symmetry. Single crystal X-ray diffraction shows that single crystals have monoclinic symmetry at room temperature with space group P1211. Electron probe microanalysis shows that single crystals are Na-rich and A-site deficient. Temperature-controlled Raman scattering shows that low temperature monoclinic-monoclinic, monoclinic-tetragonal and tetragonal-cubic phase transitions take place at -20 °C, 220 °C and 440 °C. Dielectric property measurements show that single crystals behave as a normal ferroelectric material. Relative or inverse relative permittivity peaks at ~-10 °C, ~230 °C and ~450 °C with hysteresis correspond to the low temperature monoclinic-monoclinic, monoclinic-tetragonal and tetragonal-cubic phase transitions, respectively, consistent with the Raman scattering results. A conduction mechanism with activation energies of about 0.5-0.7 eV was found in the paraelectric phase. Single crystals show polarization-electric field hysteresis loops of a lossy normal ferroelectric. The combination of Raman scattering and impedance spectroscopy is effective in determining the phase transition temperatures of (K1-xNax)NbO3.

Derivatives of Pyrimidine Nucleosides Affect Artificial Membranes Enriched with Mycobacterial Lipids.

The mechanisms of action of pyrimidine nucleoside derivatives on model lipid membranes of various compositions were studied. A systematic analysis of the tested agents' effects on the membrane physicochemical properties was performed. Differential scanning microcalorimetry data indicated that the ability of nucleoside derivatives to disorder membrane lipids depended on the types of nucleoside bases and membrane-forming lipids. The 5'-norcarbocyclic uracil derivatives were found to be ineffective, while N4-alkylcytidines demonstrated the most pronounced effects, significantly decreasing the dipalmitoylphosphocholine melting temperature and cooperativity of phase transition. The elongation of hydrophobic acyl radicals potentiated the disordering action of N4-alkylcytidines, while an increase in hydrophilicity due to replacing deoxyribose with ribose inhibited this effect. The ability of compounds to form transmembrane pores was also tested. It was found that 5-alkyluridines produced single, ion-permeable pores in phosphatidylglycerol membranes, and that methoxy-mycolic acid and trehalose monooleate potentiated the pore-forming activity of alkyloxymethyldeoxyuridines. The results obtained open up perspectives for the development of innovative highly selective anti-tuberculosis agents, which may be characterized by a low risk of developing drug resistance due to the direct action on the membranes of the pathogen.