Journal of Sol-Gel Science and Technology最新文献

In-situ nasal gel for treating Cerebral Arteriosclerosis (CA) has been developed to deliver tolperisone directly to the brain, bypassing the blood-brain barrier (bbb) and first-pass metabolism, resulting improving CNS bioavailability. A 3² factorial design was employed to optimize the formulation using varying thermosensitive polymer (Poloxamer 407) and mucoadhesive polymer (HPMC/K4M) concentrations to evaluate the gelation temperature and mucoadhession. Nasal thermogelling System exhibit significant results in the range, % drug content 95.14 ± 0.29–98.70 ± 0.5, gelation time <1 min, gelation temperature 32 ± 0.32–36.2 ± 0.29, gel strength < 36 ± 0.22 seconds, and mucoadhesive strength <3621 ± 30 dyn/cm². The cumulative % tolperisone release for formulations F3, F6, and F9, each with different HPMC:K4M concentrations (0.2%, 0.4%, 0.6% w/v) but a constant 20% w/v of Poloxamer 407, was 87.8%, 82.65%, and 74.65%, respectively, after 8 h. This indicates that higher HPMC K4M concentrations resulted in reduced drug release. At lower HPMC K4M concentrations, higher flux values were observed, and at higher concentrations, flux increased due to polymer cross-linking. Optimized batches F3, F6, and F9 initially showed higher flux of 0.481 ± 0.023, 0.441 ± 0.019, and 0.316 ± 0.015, respectively. The histopathological analysis confirmed the formulation’s safety, demonstrating its potential for targeted and effective CA treatment with lower systemic toxicity than oral administration.

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This study investigates the impact of Se⁴⁺ ion substitution on the electrical and dielectric properties of CoSe_3xFe_2-4xO₄ (x ≤ 0.1) nanospinel ferrites (Se-CFO NSFs) synthesized via the sol-gel method. DC conductivity measurements show a significant peak at a substitution ratio of x = 0.06, accompanied by a reduction in activation energy, suggesting improved electron mobility. AC conductivity analysis demonstrates both frequency and temperature dependence, with increased conductivity at lower frequencies, attributed to enhanced charge carrier mobility. The dielectric constant and dielectric loss exhibit notable changes at different Se ion substitution levels, with x = 0.06 showing enhanced polarization effects due to Se⁴⁺ incorporation. The dissipation factor is found to be higher at lower frequencies, correlating with an increase in polarization. Complex modulus studies, including Cole-Cole plots, reveal semicircular arcs indicative of multiple relaxation processes, with variations dependent on frequency, temperature, and Se⁴⁺ substitution levels. The ImZ/ReZ ratio as a function of frequency provides detailed insights into the material’s electrical properties, including conductivity and polarization effects, which are influenced by changes in temperature, frequency, and substitution ratio. The Nyquist plot of complex impedance (-ImZ vs. ReZ), measured up to 1.0 MHz at temperatures ranging from 20 to 120°C, and Se substitution levels between 0.02 and 0.10, highlights the behavior of Se-substituted CoFe₂O₄ NSFs. The electrical equivalent circuit model based on R(CR)(QR)(CR) from Cole-Cole impedance functions is thoroughly examined to understand these electrical changes. This extensive analysis offers valuable insights into how Se⁴⁺ ion substitution modifies the structural, electrical, and dielectric properties of CoFe₂O₄ spinel ferrites, highlighting their potential for applications in electronic devices requiring tunable conductivity and dielectric behavior.

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The anti-reflective film is one of the important and economical ways to improve the photoelectric conversion efficiency of solar cells. To enhance the weatherability of sol-gel derived SiO₂ antireflection films, a hybrid silicon source system consisting of isobutyl triethoxysilane (IBTS) and tetraethyl orthosilicate (TEOS) was employed for fabricating porous anti-reflection coatings via dip-coating, using polyethylene glycol monomethyl ether (mPEG) as the pore-forming agent. This study systematically investigated the influence of IBTS concentration on the film’s structural and optical properties. The results revealed a non-monotonic dependence of both film porosity and optical transmittance on IBTS content, with optimal performance achieved at intermediate concentrations. When the amount of IBTS was 6 ml, the film’s average transmittance within 380–1100 nm wavelength range reached the maximum 93.61%, 4.4 percentage points higher than that of the glass substrate. Moreover, the film’s adhesion strength reached grade 0, and its hardness was greater than 9 H. When the coated glass was used as the cover instead of the substrate glass, the efficiency of monocrystalline silicon solar cells improved from 11.64% to 12.26%, a relative increase of 4.93%. The film’s hardness and adhesion strength changed little after 100 h of UV lamp irradiation, while the average transmittance in the range of 380–1100 nm decreased with 0.45 percentage points. After immersion in hydrochloric acid solution for 80 h, the film hardness decreased to 8H, and the adhesion strength decreased to grade 1, while the transmittance increased with the increase of immersion time. When the immersion time reached 100 h, the film’s transmittance increased 0.81%.

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The fabrication of reliable and highly efficient electrocatalysts for water electrolysis poses a significant challenge in fulfilling the energy demand. In the present work, a hybrid electrocatalyst of manganese ferrite and rGO is fabricated for OER. The MnFe₂O₄@rGO composite was synthesised by a hydrothermal approach, where MnFe₂O₄ nanoparticles were prepared and then integrated with reduced graphene sheets (rGO). The morphological and structural properties of MnFe₂O₄, rGO, and MnFe₂O₄@rGO were studied using different physicochemical techniques. The 3-electrode study under alkaline (1.0 M KOH) conditions was conducted to estimate the electrochemistry of the material. The synthesised composite exhibited an overpotential of 239.2 mV at (10 mA/cm²) current density. The electrocatalysts showed high transfer of electrons with a Tafel value of 39.7 mV/dec. Moreover, the stability test showed that the material can withstand 40 h. The impedance test also confirmed that the composite has low resistance and high conductivity. The synergetic effect of rGO and manganese ferrites helps attain high conductivity. All the electrochemical results confirmed that the fabricated MnFe₂O₄@rGO composite could be used in place of noble metals as suitable and effective electrocatalysts.

This study aims to investigate the structural, morphological, optical, and photocatalytic properties of MgO and Cu-doped MgO thin films with Cu concentrations of 3, 6, and 9 at.% deposited on glass substrates via the sol–gel spin-coating technique. The effects of Cu doping on these properties of the thin films were investigated using scanning electron microscopy (SEM), energy‑dispersive X‑ray spectroscopy (EDX), X‑ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM), photoluminescence (PL) spectroscopy, and UV–Vis spectrophotometry. The structural analysis indicated that the deposited films exhibited a cubic crystal structure without secondary phases, with (2 0 0) preferred orientation. Crystallite size decreased from 31.25 nm to 15.48 nm with the introduction of dopants. Additionally, the SEM images revealed that doping with Cu switched the nanowall structures to rounded. The surface roughness tends to decrease with Cu-doping, as observed from the AFM topographical image. Optical characterization indicated a redshift in the absorption edge and a decrease in band gap energy from 3.93 eV to 3.82 eV based on Tauc plots for direct transitions (αhν)² vs hν, alongside increased refractive index (n), extinction coefficient (k), and dielectric constant (ε), increased with Cu content, particularly in the visible region. Photoluminescence (PL) intensity diminished with rising Cu content, suggesting suppression of radiative recombination. Finally, photocatalytic experiments using methylene blue (MB) under natural sunlight showed that 6% Cu-doped MgO films achieved the highest degradation efficiency, exceeding 97% within 200 min. These findings demonstrate that Cu doping effectively tunes the optical and catalytic behavior of MgO thin films, making them promising candidates for solar-driven environmental remediation and optoelectronic applications.

In present study, nano-sized DyFeO₃ rare-earth orthoferrite was successfully synthesized and characterized for its structural, morphological, and photocatalytic properties. X-ray diffraction (XRD) confirmed a single-phase orthorhombic perovskite structure with high crystallinity and phase purity, further validated by Rietveld refinement. Raman and FTIR spectroscopy supported the structural findings, revealing characteristic vibrational modes and strong bonding interactions within the FeO₆octahedra. FESEM analysis showed uniformly distributed nanoparticles with minimal aggregation, and BET measurements indicated a high surface area and mesoporous nature. The DyFeO₃-CNT composites exhibited enhanced photocatalytic activity under visible light, degrading Rhodamine B dye with 79% efficiency in 70 min-significantly higher than the 36% efficiency of pure DyFeO₃. Kinetic studies revealed improved rate constants due to effective charge separation and higher surface accessibility facilitated by the Carbon nanotubes (CNTs). These results demonstrate that DyFeO₃-CNT nanocomposites are promising materials for advanced photocatalytic and environmental remediation applications.

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The diffusion of specific chain segments, end groups, and incorporated nanofillers across bulk/surface interfaces of coatings contributes to fouling-resistant and even corrosion-inhibition performances. This largely depends on their sizes, the degree of cross-linking within the polymer chains, and how they were chemically grafted. In the present study, an amphiphilic oligomer is first synthesized from by telomerization, before preparing a hybrid polymer blend with a new organosilicon synthesized via the hydrosilylation reaction. This new cross-linked organosilicon/telomer blend with amphiphilic segments, reinforced CaO/SiO₂NPs (SEB1-4), provides improved fouling- and corrosion-resistant performances for low-carbon steel in seawater. Corrosion protection by this polymer coating depends on the blend ratio between the organosilicon gel (OSG) and amphiphilic telomer (AT) precursors. The order of increased corrosion protection is SEB1 (1:1) > SEB2 (1:2) > SEB3 (2:1) > SEB4 (3:1). Compared with an unreinforced coating (i.e., no nanofillers), this reinforced polymer exhibited enhanced antibacterial activity when coated on steel, eliminating the chance of biofilm buildup and surface adherence for a marine bacterium, Pseudomonas aeruginosa. Integrating these nanofillers promoted improved coating adhesion, mechanical strength, and surface protection, while unreinforced coatings exhibited severe disbonding and adhesive/cohesive failures.

Thick and homogeneous coatings with thickness gradients have been developed from aqueous Na-, K- and Li-silicates, also commonly referred to as waterglasses. Thermal treatment of such coatings to 250  °C has allowed to evidence the existence of a critical thickness (CT) below which the coating homogeneity stays intact while intumescence/foaming, crystallization or cracking may be observed above the CT, depending upon the starting composition. Intumescence is observed above CT especially in the case of Na- and K-silicates. Below the CT, water issued from condensation may diffuse outside the film resulting in a reduced thickness of the coating, evidenced from SEM images. Above CT, condensation leads to a non-permeable coating so that water cannot diffuse outside and, thus, creates a foam. Raman spectroscopy depth slice measurements on a flat 20 µm thick coating suggest that the non-permeable coating formed at 150 °C has a reduced amount of water in comparison to the as-deposited coating dried at 55 °C.

Silica aerogel has been widely used in aerospace, energy construction, petrochemical industry. The most significant challenge in the commercialization of aerogels is the high cost. One of the most promising avenues for addressing this issue is the low-cost ambient pressure drying process, which is regarded as a crucial means of reducing the production cost. This study aims to facilitate the industrialization of aerogels prepared via ambient pressure drying. The physicochemical properties of aerogel strongly correlate to the modification methods, such as aging and surface hydrophobicity treatments. Among these methods, solvent exchange plays a key role in synthesizing silica aerogel by ambient pressure drying. In order to facilitate the ambient pressure drying preparation of silica aerogel for industrial application, we designed an efficient automatic solvent exchange device for silica wet gels, and systematically studied the influence of solvent exchange on the physicochemical properties of silica aerogel via ambient pressure drying. After aging and surface hydrophobic modification, the silica wet gels undergo solvent exchange at different temperatures and times. The results show that with the increase of temperature and time, the moisture content of solvent in silica wet gel, as well as the bulk density and thermal conductivity of silica aerogel decrease. Moreover, we studied the effect of solvents with different surface tensions on the physicochemical properties of silica aerogels. The utilization of solvents with low surface tension can result in the production of silica aerogels with a lower bulk density (0.101 g/cm³) and thermal conductivity (0.016 W/m·K), while simultaneously enhancing the specific surface area, pore diameter and pore volume. These findings emphasize the importance of solvent exchange to improve the ability of gel particle network skeleton to withstand irreversible pore collapse via ambient pressure drying.

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