Differential Scanning Calorimetry Measurements Research Articles

Effect of Monosaccharides Including Rare Sugars on the Bilayer Phase Behavior of Dimyristoylphosphatidylcholine

We observed bilayer phase transitions of dimyristoylphosphatidylcholine (DMPC) in aqueous solutions of four kinds of monosaccharides, namely, D-glucose, D-fructose, D-allose and D-psicose, using differential scanning calorimetry (DSC). D-allose (C3-epimer of D-glucose) and D-psicose (C3-epimer of D-fructose) are rare sugars. We performed DSC measurements using two types of sugar-containing sample dispersions of the DMPC vesicles: one is a normal sample dispersion with no concentration asymmetry between the inside and outside of the vesicles and the other is an unusual sample dispersion with a concentration asymmetry. DSC measurements using normal sample dispersions with different sugar concentrations revealed that the temperatures and transition enthalpies of the pre- and main transition of the DMPC bilayer membrane did not significantly depend on the sugar concentration for all monosaccharides. DSC measurements using the unusual sample dispersions demonstrated that the concentration asymmetry caused the splitting of the endothermic peak of the main transition similarly irrespective of the sort of monosaccharides present. From all these DSC results, we conclude that (i) most monosaccharide molecules exist in the bulk water phase, (ii) no specific interaction depending on the molecular structure of each monosaccharide directly occurs between the DMPC and each monosaccharide molecule, and (iii) almost all the effects of the monosaccharides observed in this study are understandable as the general colligative properties of solutions.

Dissolving alginate-based blend microneedles with enhanced mechanical performance for transdermal delivery of vitamin B12

Transdermal delivery of vitamin B12 (Vit-B12) is challenging due to its high hydrophilicity and molecular weight that limit permeation through the skin. Polymeric microneedles (MNs) have been demonstrated to facilitate enhanced transdermal delivery of various drugs with different properties, by piercing the outermost layer of the skin barrier in a minimally-invasive manner. Although sodium alginate (SA) has been widely investigated and used for pharmaceutical and biomedical applications, MNs made of pure SA, exhibit poor mechanical properties. Therefore, this study investigates the effect of incorporating different excipients into SA MNs, to enhance their insertion ability and mechanical performance, by a modified vacuum deposition micromolding method. Among these, poly(vinylpyrrolidone) (PVP) and polyethylene glycol (PEG)-containing SA MNs at a ratio of 1:8 show improved mechanical strength with minimal height reduction (< 10%) at all tested forces, and higher insertion capabilities into a skin-simulant parafilm model (> 65% in the second layer), compared to control SA MNs. Consequently, Vit-B12 was successfully loaded and concentrated into the MN shafts of the lead formulations, by the addition of hydroxypropyl cellulose to the baseplate. Vit-B12 MNs were characterized by means of fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) measurements, drug loading and dissolution kinetics. The MNs exhibited adequate mechanical properties and a complete drug release within 30 min, while a considerable fraction was released after few minutes. The present study shows promising findings regarding the potential use of SA in the preparation of dissolving MNs with enhanced mechanical performance for transdermal delivery of Vit-B12. However, further preclinical investigations are necessary to comprehensively evaluate their therapeutic efficacy. Additionally, this work suggests that alginate-based blend MNs may have a potential application in the delivery of other hydrophilic and large compounds for improved therapeutic outcomes.

Influence of GeO2/TeO2 ratio on thermal, structure and spectroscopic properties of Dy3+-doped tellurite-germanate glass

Dy2O3-doped tellurite-germanate glasses with an increase of GeO2/TeO2 ratio (TGZ) were synthesized and characterized through X-ray diffraction (XRD), differential scanning calorimetry (DSC), Raman, absorption, and emission spectra measurements. XRD spectra of Dy3+-doped TGZ glass confirmed the amorphous structure. The TGZ glass possess the higher anti-crystallization abilities than that of the pure tellurite glass. Raman spectroscopy showed that the amount of [TeO3] and [TeO3+1] units in the glass network were gradually decreased by increasing the ratio of GeO2 to TeO2. The result was further supported by the optical band gap energy of the TGZ glass. The luminescence intensity of the sample increased with an increase in GeO2 content and reached a maximum value at 10 mol%. The chromaticity coordinates of CIE 1931 were in the warm white light range, and the corresponding color temperature range was 3400 K–3600 K. The results showed that the addition of GeO2 to Dy3+-doped tellurite glass can improve the thermal stability and luminescence performance of the white light-emitting band.

High-filler content electrospun fibers from biodegradable polymers and hydroxyapatite: Toward improved scaffolds for tissue engineering.

One of the key challenges in tissue engineering area is the creation of biocompatible scaffolds that support cell growth and mimic the structural and mechanical properties of native tissues. Among various materials used for scaffold fabrication, composite materials based on biodegradable polymers reinforced with bioactive inorganic fillers have attracted significant attention due to their properties. One of the important problems with the preparation of composite electrospun fibers is the low filler content in the fiber. This study aims to select the best composition for electrospun polymer fibers in terms of potential application in tissue engineering. The effect of the viscosity of polymer solution/dispersion and filler content on the structure and properties of the fibers was determined. Morphology and filler content were compared. Series of electrospun composite fibers were fabricated from poly(ĺ-caprolactone) (PCL), poly(L-lactic acid) (PLLA) and hydroxyapatite (HAP), containing from 10 wt% to 40 wt% HAP. The properties of the resulting composites were studied using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and viscosimetry measurements. The addition of HAP to the polymer solution caused a significant increase in viscosity, but the results showed that it is possible to obtain composite electrospun fibers even with 40 wt% filler content. Scanning electron microscopy analysis shows randomly oriented electrospun fibers with an average diameter in the range of 3.8-8.5 ěm for solution and dispersion with high viscosity (1,210-2,000 mPa·s) and significantly larger diameters (approx. 12 ěm) for the PCL solution (326 mPa·s). It is possible to transform the composite dispersion from biopolymers and HAP into nonwoven fabrics at up to 40 wt% filler content. Due to their unique properties, such materials are promising for application in tissue engineering.

Development and Application of a Cooling Rate Dependent PVT Model for Injection Molding Simulation of Semi Crystalline Thermoplastics.

This technical paper delves into the creation and application of an enhanced mathematical model for semi crystalline thermoplastics based on the Pressure-Volume-Temperature (PVT) Two Domain Tait Equation. The model is designed to incorporate the impact of the cooling rate on the specific volume of the material. This is achieved by utilizing Flash differential scanning calorimetry (fDSC) measurements, thereby ensuring a direct correlation to the actual behavior of the material in reality. The practical application of the model in the context of injection molding simulation was also considered. This was done by integrating the mathematical model into the Moldflow software via the Solver API. The paper underscores the discontinuity issue inherent in the traditional Tait equation with cooling rates and proposes a solution that guarantees a correct transition from the liquid to the solid phase, even at high cooling rates and pressures. The results demonstrated a realistic PVT curve across a wide range of cooling rates and high pressures. The model was put to the test using a 3D tetrahedron meshed calculation model in the injection molding simulation. This study marks a significant step forward in the simulation of injection molding processes, as it successfully bridges the gap between real material properties and simplified simulation, paving the way for more accurate and efficient simulations in the future.

Thermal behavior of polymers and copolymers based on plant oils with differing saturated and monounsaturated content

AbstractPlant oil‐based acrylic monomers from hydrogenated sunflower (HFM), palm (PMM) and castor (CSM) oils were polymerized to investigate the effect of chemical composition on polymer phase transitions at temperatures relevant to physiological range. While HFM and PMM possess a highly differing content of saturated palmitic and stearic acids combined with unsaturated fatty acids, CSM contains primarily fragments based on monounsaturated ricinoleic hydroxy acid (up to 90%). Differential scanning calorimetry (DSC) measurements indicate that polymers from PMM and HFM are both semicrystalline (with Tm = −6 and −13 °C, respectively), while poly(CSM) appears to be amorphous (Tg = −49 °C). Considering the similarity in polymers' molar mass (Mn = 16 000–20 000 g mol−1), the observed thermal transitions can be explained by the formation of ordered morphological domains due to the presence of saturated palmitic and stearic acid fractions in poly(PMM) and poly(HFM). For copolymers of CSM, PMM and HFM (80 wt% of monomer feed) with styrene, DSC data show two transitions corresponding to the mobility of long alkyl fatty acid side fragments and the macromolecular backbone. For copolymers of PMM and HFM, comparable values (−52.8 and −55.5 °C, respectively) were obtained, while the second transition for poly(CSM‐co‐styrene) appears at 35 °C. We attribute this higher value to the presence of hydroxyl groups in ricinoleic acid fragments of CSM serving as additional chain transfer sites and the formation of macromolecular fractions enriched with polystyrene fragments. We expect that the temperature transitions obtained can be relevant to the future use of these polymers for biomedical applications, including the synthesis of polymer brushes. © 2024 Society of Chemical Industry.

Predicting the Linear Low-Density Polyethylene Content of Custom Polypropylene Blends and Post-Consumer Materials Using Rheological Measurements.

Contributing to a sustainable economy requires the use of pure recycled materials. Analyzing polyolefin post-consumer materials and cross-contaminations in these materials is an essential part in ensuring consistent product quality. Therefore, the aim of this work was to quantify the linear low-density polyethylene (LLDPE) content in polypropylene (PP)-dominant strips. The materials investigated included virgin PP, custom PP-LLDPE blends and PP post-consumer recyclates. To this end, differential scanning calorimetry (DSC) and parallel-plate rheometry were used. For complementary measurements, Raman spectroscopy and atomic force microscopy (AFM) were employed, confirming the morphological occurrence of LLDPE enclosed in PP up to 30 wt%. The DSC measurements demonstrated that the evaluated specific melt and recrystallization enthalpies alone are insufficient to quantify the LLDPE content, especially at 1-10 wt%. The rheometric results showed a strong correlation between the cross-over point (COP) and zero-shear viscosity for pure PP grades, and there was a deviation from this correlation depending on the LLDPE content in the PP-LLDPE blends. An approach for determining low (1-15 wt%) and medium (up to 30 wt%) LLDPE quantities in PP via two mathematical models is proposed based on the rheometric measurements of custom blends and can be applied to assess the level of LLDPE contamination in PP post-consumer materials.

Impact of hydrothermal aging on microstructure transformation in Poly(L‐lactide) nonwovens under tension in condition close to a living organism

AbstractThe analysis of mechanical properties and structure of bioresorbable polymer nonwoven materials is an important area of research in the medical industry, the properties and structure of which directly affect the processes of cellular activity. In this work, the processes of reorganization of the fibrous microstructure of poly(l‐lactide) nonwoven materials under uniaxial tension in a water environment were investigated. The study which included volumetric ultrasound imaging, mechanical testing, differential scanning calorimetry, X‐ray diffraction, and melting rate measurements was the first attempt to identify correlations between the mechanical behavior of fibrous meshes and changes in the supramolecular structure of the polymer during 3 months of hydrothermal aging T = 37°C. An increase in crystallinity by 4%, a shift of glass transition temperature by 4°C, and a 2 times increase in melt flow rate under hydrolysis were indicated degradation of the amorphous phase. Local degradation of the amorphous phase of fibers led to the formation of surface cracks, an increase in the number of microcracks during hydrothermal aging resulted in a decrease in the mobility of fibers in the volume of the nonwoven material and a decrease in the elasticity of the entire nonwoven material, which was revealed using the volume ultrasound imaging and optical microphotographs.

Impact of statistical poly(propylene co-ethylene) on the thermo-mechanical properties of high-density polyethylene

A series of high-density polyethylene and a statistical copolymer of poly(propylene-co-ethylene) blends in a wide range, namely (0, 10, 20, 30, 40, 50, 60,70, 80, 90, 100) abbreviated as HDPE/VM were systematically investigated by using a rheometer, differential scanning calorimetry (DSC) measurements, polarized optical microscopy (POM) and tensile tests. Rheometer results show that adding VM decreases dynamic viscosity, storage, and loss modulus. Han plot shows that HDPE and VM are compatible and miscible in the range from 20 to 60 VM % in the molten state. DSC results show little nucleation effect of VM on HDPE (HDPE’s melt crystallization temperature shifts 2 °C higher). Moreover, a linear composition dependence of ∆cp ∆Hc, ∆Hm shows that PE and VM are most probably compatible in the molten state in composition range from 20 to 60%. However, upon crystallization, the VM and PE domains occur distinctively. The results of the tensile tests demonstrated a decrease in elastic modulus, yield stress, and ultimate tensile strength as VM content increased. At low VM content (less than 20%), high elongation at break was detected for the blends, and very fine spherulites of HDPE were found across the sample by POM.

Thermal and structural analysis of binary mixtures of pyrimidine liquid crystals using Modulated Differential Calorimetry and Synchrotron X-ray Diffraction measurements.

We present a systematic experimental dataset on the temperature dependence of specific heat capacity in a binary mixture of the second and seventh homologous series of 5-alkyloxy-2-(4-nonyloxy-phenyl) pyrimidine(PhP) liquid crystal compound. These binary mixtures exhibit nematic, smectic-A, and smectic-C phases within a concentration range of xPhP1 = 0 to 0.45. The liquid crystalline phases are structurally characterized using synchrotron X-ray diffraction. We determine the apparent molecular length in the nematic phase, smectic layer spacing, average distance between the long axes of molecules, correlation length, and orientational order parameters (<P2> and <P4>) as functions of temperature. The tilt angle in the SmC phase is inferred from the layer spacing data. To examine the critical behavior near the nematic to smectic A(NA) and smectic A to the smectic C (AC) phase transitions, we evaluate the critical exponents: α from specific heat capacity, β from the fitting of the temperature-dependent tilt angle, and ν‖, ν⊥from the temperature-dependent longitudinal (ξ‖) and transverse (ξ⊥) correlation lengths. Modulated Differential Scanning Calorimetry (MDSC) measurements indicate the absence of phase shift, latent heat and imaginary specific heat capacity, suggesting that the AC transitions are second-order for all binary mixtures. The results obtained from heat capacity reveal that both the AC and NA transitions exhibit non-universal behaviours with effective exponents lying between the tricritical and 3D-XY values and follow nearly identical curve with decreasing width of the Sm-A and N phases. The Josephson hyperscaling relation is verified for both the NA and AC transitions in different mixtures. Moreover, knowing the heat capacity critical exponent α and the order parameter critical exponent β, the susceptibility critical exponent γ for the AC transition can be estimated from Rushbrooke equality α+2β+γ=2, with γ values ranging from 1.015 to 1.313, indicating the system's crossover character and apparently validating the Rushbrooke equality.

Combined effects of carbon content and heat treatment on the high-temperature tensile performance of modified IN738 alloy processed by laser powder bed fusion

Laser powder bed fusion (LPBF) is an advanced manufacturing technology used in processing nickel-based superalloys, notably for aero-engine components. One such material, the LPBF-fabricated IN738 superalloy, is prone to significant cracking issues. This study found that a change in carbon content (the optimal content of which was also determined) effectively mitigated the cracking. This study has systematically investigated the impact of different heat treatments on microstructural alterations and high-temperature tensile properties. The addition of 0.55 wt.% of graphite proved effective in entirely inhibiting cracking in LPBF-fabricated IN738 specimens. Pre-alloyed IN738-M powder with the optimal carbon content was then produced and processed via LPBF to assess its formability. The as-built specimen revealed the presence of continuous carbides along the subgrain boundaries. Heat treatment promoted the transformation of substructured grains into recrystallised grains, accompanied by the precipitations of carbides and the γ' phase; their morphologies were strongly determined by the solution treatment temperature. Differential scanning calorimetry measurements were employed to elucidate the differing microstructural states following distinct heat-treatment regimens. Under a 900°C testing condition, stress-relieved (SR) specimens were found to exhibit superior performance, demonstrating an ultimate tensile stress (UTS) value of 843.6 MPa, a yield strength (YS) of 807.3 MPa and an elongation of 8.54%. Notably, SR specimens also exhibited the highest UTS and YS values at 1000°C, measuring 380.0 MPa and 346.5 MPa, respectively. This study’s findings will furnish valuable insights for researchers who aim to enhance the high-temperature tensile performance of LPBF-fabricated nickel-based superalloys.

Biochar as a UV Stabilizer: Its Impact on the Photostability of Poly(butylene succinate) Biocomposites.

In the present study, biocomposite materials were created by incorporating biochar (BC) at rates of 1, 2.5, and 5 wt.% into a poly(butylene succinate) (PBSu) matrix using a two-stage melt polycondensation procedure in order to provide understanding of the aging process. The biocomposites in film form were exposed to UV irradiation for 7, 14, and 21 days. Photostability was examined by several methods, such as Fourier transform infrared spectroscopy (FTIR), which proved that new carbonyl and hydroxyl groups were formed during UV exposure. Moreover, Differential Scanning Calorimetry (DSC) measurements were employed to record the apparent UV effect in their crystalline morphology and thermal transitions. According to the molecular weight measurements of composites, it was apparent that by increasing the biochar content, the molecular weight decreased at a slower rate. Tensile strength tests were performed to evaluate the deterioration of their mechanical properties during UV exposure, while Scanning Electron Microscopy (SEM) images illustrated the notable surface alternations. Cracks were formed at higher UV exposure times, to a lesser extent in PBSu/BC composites than in neat PBSu. Furthermore, the mechanism of the thermal degradation of neat PBSu and its biocomposites prior to and upon UV exposure was studied by Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS). From all the obtained results it was proved that biochar can be considered as an efficient UV-protective additive to PBSu, capable of mitigating photodegradation.

Enhancement of sodium ion conductivity in phosphate-based glass-ceramics by chemical substitution approach

A NASICON-type sodium-ion conducting material was synthesized via the glass-ceramic route by investigating the zinc doped Na2O–Al2O3–TiO2–P2O5 system. The glasses and glass-ceramics corresponding to the formula Na2+xAl1-xZnxTi(PO4)3 (x = 0, 0.2, 0.4, 0.6, 0.8, 1), labeled as (NAZTP-Gx) and (NAZTP-GCx) respectively, were characterized using different techniques. Differential Scanning Calorimetry (DSC) measurements were carried out to identify the characteristic temperatures, the glass transition (Tg) and the crystallization temperature (Tc). X-ray Diffraction (XRD) analysis of the glass-ceramics confirmed the formation of a solid solution Na2+xAl1-xZnxTi(PO4)3 NASICON phase, Theoretical calculations employing the Perdew–Burke–Ernzerhoff generalized gradients approximation (PBE-GGA) model supported the potential substitution of aluminum by zinc in the octahedral site in the NASICON-phase. Further structural insights were obtained through Infrared (IR) and Raman spectroscopies. Scanning electron microscopy (SEM) analysis revealed a distinct flower-like shape of the formed crystallites in the glass-ceramic NAZTP-GC0.2. Electrical characterization using electrochemical impedance spectroscopy (EIS) demonstrated that the NAZTP-GC0.2 sample exhibited the highest ionic conductivity at 300 °C, reaching 4.1 × 10−5 (Ω−1 cm−1) with an activation energy of 0.25 eV. The DC polarization was performed on the NAZTP-GC0.2 glass-ceramic, revealing that the ions are the main charge carriers in the sample. This comprehensive analysis provides valuable insights into the partial zinc doping of NASICON glass-ceramics, offering potential for improved performance as solid electrolytes in various applications.

Effect of TiO2 nanoparticles on the assembly of a copolymer-clay dispersion

Nanocomposites based on copolymer and clay minerals are attracting increasing attention as they are appropriate for extensive applications. In this work, we present results from an experimental study on the effects of TiO2 nanoparticles on a pluronic-F127/laponite water solution in the sol state. Differential Scanning Calorimetry (DSC), Dynamic Light Scattering (DLS) and Fourier Transform Infrared Attenuated Total Reflection Spectroscopy (FTIR-ATR) were used to characterize the systems. By DSC and DLS measurements the occurrence of micellization was first investigated. The temperature induced self-assembly was then studied by DLS identifying three relaxations associated to differently sized diffusing structures. The correlation between dynamics and bonding structure was thoroughly investigated by analyzing some specific infrared vibrational bands. In particular, the study of the characteristic absorption band of the ether groups in the dry state allowed to evaluate the amorphous/crystalline component evidencing the presence of more extended conformations in presence of the higher TiO2. Finally, the analysis of the bending mode for the residual water provided valuable insight about structural OH groups enabling a distinction between different types of water molecules associated to the copolymer/nanoparticle systems.

In situ monitoring of CO2$$ {}_2 $$ sorption on polyethylenimine dynamics through broadband dielectric spectroscopy

AbstractChemical reactions between carbon dioxide (CO) and amine have been extensively characterized, however, their influence on the dynamics of polyamines remains largely unexplored. In this work, we compare the dynamics of polyethylenimine (PEI) before and after CO absorption through broadband dielectric spectroscopy (BDS). The molecular processes of bulk PEI are very different from those of thin film PEI, highlighting an interesting interface and nano‐confinement effect. Detailed analyses show CO absorption slows down the PEI dynamics, which is consistent with an elevated glass transition temperature of PEI upon CO absorption from differential scanning calorimetry measurements. Further in situ kinetic measurements demonstrate nonmonotonic changes in relaxation times or dielectric amplitudes of some relaxation processes during CO sorption or desorption, suggesting an intriguing interplay between CO chemisorption and the dynamics of PEI. These results demonstrate that BDS is a powerful platform to resolve the temporal dynamics changes of polyamines for CO capture.

Evaluating passive PCM performance in building envelopes for semi-arid climate: Experimental and numerical insights on hysteresis, sub-cooling, and energy savings

This study evaluates the performance of macro-encapsulated Phase Change Materials (PCMs) integrated into building envelopes for semi-arid climates, focusing on typical Moroccan construction using hollow concrete blocks. The primary objective is to assess the discrepancies between experimental and numerical analyses, particularly in hysteresis, sub-cooling, and energy savings. Given the widespread reliance on numerical tools like EnergyPlus for PCM simulations, the accuracy of manufacturer-provided latent heat values is investigated. The methodology involves constructing two identical test buildings, one equipped with PCM panels and another as a reference. Experimental data were collected in June 2023, assessing temperature fluctuations and energy savings. Differential Scanning Calorimetry (DSC) tests at varying scanning rates were conducted to analyze PCM behavior, including hysteresis and sub-cooling effects. Numerical simulations were then performed to compare energy performance. Besides, the results reveal that sub-cooling significantly limits PCM efficiency, with only 43 % of the PCM's latent heat capacity utilized. At the same time, hysteresis was found to be negligible in the field test. Cooling energy consumption was reduced by 20 %, with a corresponding 2.3 °C reduction in temperature fluctuations. However, the PCM's latent heat potential is underutilized due to sub-cooling. This research underscores the need for conducting DSC measurements at specific scanning rates to reflect regional climate conditions and suggests that simulation models should adjust latent heat utilization of the PCM. The study advocates for the use of composite PCMs, which could mitigate sub-cooling and enhance overall performance. These findings contribute to improving PCM integration in passive building designs, offering practical recommendations for better energy efficiency in semi-arid climates.

Development and in vitro characterization of new carnosine-loaded liposomal formulations.

Carnosine is an endogenous dipeptide characterized by a multimodal mechanism of action. However, its clinical potential is limited by serum and cytosolic carnosinases, which significantly reduce its bioavailability. Based on that, different research groups have worked on the development of new strategies able not only to prevent its rapid metabolization but also to improve its distribution and specific targeting. In the present study, the development and in vitro characterization of new liposomal formulations loaded with carnosine are described. Nanoliposomes, produced through Thin-Layer Hydration followed by Extrusion method, were first investigated for their physicochemical stability. Photon correlation spectroscopy and electrophoretic light scattering, assessing the stability of the formulations, showed a strong homogeneity-oriented tendency for up to two months. Particle size, polydispersity index, and zeta potential were determined through dynamic light scattering and electrophoretic light scattering, demonstrating an almost neutral charge of the formulation and an effective encapsulation of carnosine. The morphology assessment performed via scanning electron microscopy showed good conformity and polydispersity. Differential scanning calorimetry measurements suggest the ability of carnosine to stabilize the large unilamellar vesicles. Lastly, the newly developed carnosine-loaded liposomal formulations also showed a good safety profile in human microglia.

New Ibuprofen Cystamine Salts With Improved Solubility and Anti-Inflammatory Effect.

Two novel ibuprofen cystamine salts (IBU-CYS 1 and IBU-CYS 2) are synthesized by coupling the anion of ibuprofen with cystamine dihydrochloride in 1 : 1 and 2 : 1 ratio to improve the solubility and bioavailability of ibuprofen. The salts are characterized by 1HNMR, FT-IR and UV-Vis spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TGA, DTA) and X-ray diffraction measurements. IBU-CYS 1 and IBU-CYS 2 show higher solubility (6.11 and 7.81 mg/mL) compared to ibuprofen (0.04 mg/mL) in water. IBU-CYS2 was encapsulated into 2-hydroxyethyl methacrylate: poly (ethylene glycol) acrylate hydrogels for enhanced delivery. The in vitro studies in PBS (pH 7.4) indicate that the salts are effective in relieving inflammatory responses induced by lipopolysaccharide in RAW264.7 macrophage cells (nitrite inhibition percentages of IBU-CYS 1, IBU-CYS 2 and ibuprofen: approximately 34.29, 27.03 and 31.50 respectively) while indicating no cytotoxicity. Therefore, these salts may be promising candidates for the development of effective formulations of this drug.

Phonon Transport in Supramolecular Polymers Regulated by Hydrogen Bonds.

Supramolecular polymers hold promise in thermal management applications due to their multistability, high responsiveness, and cost-effectiveness. In this work, we successfully regulate phonon transport at the molecular level in supramolecular polymers by adjusting the strength of intermolecular hydrogen bonding. We synthesized three supramolecular polymer fibers with thermal conductivity differences of up to 289% based on melamine (M) and three simple positional isomers of hydroxybenzoic acid. Differential Scanning Calorimetry (DSC) measurement revealed discrepancies in thermal stability of the polymers, where structures with higher stability exhibited enhanced thermal conductivity. Fourier Transform Infrared Spectroscopy (FTIR) measurement and Density Functional Theory (DFT) calculations indicate that these differences arise from variations in hydrogen-bonding strengths at different bonding sites. Higher hydrogen-bonding strength leads to more stable thermal pathways, reduces phonon scattering, and increases thermal conductivity. Our findings provide valuable insights into controlling the thermal conductivity of polymer fibers, paving the way for applications in phonon-based thermal devices.

Characterization and Crystal Structural Analysis of Novel Carvedilol Adipate and Succinate Ethanol-Solvated Salts

Two ethanol-solvated adipate and succinate salts of carvedilol (CVD), a Biopharmaceutics Classification System class 2 drug, were synthesized by crystallizing ethanol with adipic acid (ADP) and succinic acid (SUA). Proton transfer from ADP and SUA to CVD and the presence of ethanol in the two novel compounds were confirmed using powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and single-crystal X-ray diffraction measurements. The two novel ethanol-solvated salts exhibited enhanced solubility and dissolution rates compared with pure carvedilol in phosphate buffer (pH 6.8). Additionally, the morphologies and attachment energies of the two novel compounds and pure CVD were calculated based on their single-crystal structures, revealing a correlation between attachment energy and dissolution rate.