The micellization behavior of urea-based cationic gemini surfactants was investigated using small-angle neutron scattering (SANS) with multi-model form factor analysis. A homologous series of surfactants with urea group included in the hydrophobic tail and polymethylene spacers consisting of two to ten methylene units was analyzed using three form factor models: a core–shell ellipsoid and two variants of homogeneous ellipsoids. The results from all models show a consistent trend of the micelle structures, confirming that the spacer length critically influences micellar geometry, aggregation number, and hydration. The surfactant with four CH2 groups in the spacer formed the largest micelles with the highest aggregation number, while longer spacers led to progressively smaller, more compact aggregates. The shell hydration—quantified as the volume fraction of heavy water within the hydrophilic region—decreased systematically with increasing spacer length due to enhanced hydrophobicity of the headgroup-spacer region. Intermicellar interactions, modeled as screened Coulomb interaction using the rescaled mean spherical approximation (RMSA), revealed the strongest electrostatic repulsion for the case of four methylene groups in the spacer, corresponding to the highest micellar charge and largest interparticle spacing. The observed spacer-dependent trends were robust across all modeling approaches, demonstrating that the spacer length serves as a key structural determinant of self-assembly in this type of urea-based gemini systems. These findings provide insight into the design of gemini surfactants with tailored aggregation behavior for applications in drug delivery, nanostructure templating, and solubilization technologies.

Reducing losses in inductor core materials allows further miniaturization and increase of efficiency in power converters. Nanocomposites containing superparamagnetic 11 3 nm - particles in a polyvinyl alcohol polymer matrix were developed as printable and castable inductor core materials for MHz range frequencies. The aqueous synthesis resulted in nanocomposites of well-dispersed particles with volume fractions ranging from 10% to 45%. The nanocomposite is eddy current free, has high volume susceptibility up to 17, and a constant AC response in the Hz-kHz range. Hysteresis measurements at 100-900 kHz show that power losses scale as -field squared and with frequency to the power of 1-1.3, indicating that the only loss mechanism is high-frequency hysteresis. For an induced -field amplitude of 30 mT, commonly used in inductor core materials for power electronics, the losses are on the order of - kW . These losses can be reduced by using more monodisperse particles. The presented nanocomposite is easily integrated into micro-fabrication methods, demonstrated by depositing nanocomposite cores on printed circuit board inductors. The inductors with nanocomposite core, measured up to 100 MHz, display an increase in inductance compared to air-core inductors. This showcases superparamagnetic nanocomposites as relevant candidates for high-frequency applications such as portable electronics.

Efficient adsorbents and nanozyme-like materials are of growing importance in environmental technologies. Here, we report a simple and potentially scalable approach for the immobilization of biochars onto nonwoven acrylic textiles, yielding composite materials with good retention of immobilized biochar during aqueous treatment and combined adsorption and peroxidase-like activities. The structure of native and biochar-modified textiles was characterized by scanning electron microscopy and small-angle X-ray scattering, confirming the presence of biochar particles on fiber surfaces and within the inter-fiber space, as well as nanoscale structural changes induced by biochar incorporation. Textile-bound biochars exhibited peroxidase-like activity toward N,N-diethyl-p-phenylenediamine in the presence of hydrogen peroxide and enabled effective decolorization of methylene blue. Adsorption alone resulted in 61% dye removal after 240 min, while the combined adsorption-catalytic process achieved 74% decolorization. Modification of the textile-bound biochar with copper ions further enhanced the peroxidase-like activity, increasing dye removal to 85% under identical conditions. The optional incorporation of a magnetic iron wire allows facile magnetic handling of the composite. Owing to its low cost, simplicity of preparation, and dual functionality, the textile-bound biochar composite represents a promising proof-of-concept platform that may warrant further development for dye removal and related environmental applications.

Microalgae-derived vesicles (AGVs) were investigated as potential carriers for therapeutic biomacromolecules. AGVs were prepared by rehydration of a lyophilisate of proteolipid ghost membranes from Dunaliella tertiolecta and subsequent extrusion or sonication. Based on our results, extrusion is suggested to be a more suitable method because of the low loss of the lipid and protein content. Applying small-angle neutron scattering and dynamic and electrophoretic light scattering, we found that the formed AGVs are spherical, unilamellar, with moderate polydispersity, and a negative surface charge of -27 mV. EPR findings show that they retain the membrane dynamics, and possibly the degree of lipid chain saturation, of the ‘mother’ algal cells. The drug-binding efficiency of the reconstructed AGVs was tested for two model biomacromolecules, DNA and BSA, using an ethidium bromide exclusion assay and tryptophane autofluorescence, respectively. The electrostatic interaction between AGVs and DNA polyanion was mediated by Ca2+ ions, while for the interaction of BSA with AGVs hydrophobic interactions are assumed to play a dominant role. For both macromolecules tested, 40% binding of the total drug amount was achieved by passive incubation, which indicates that reconstructed AGVs might expand the repertoire of potential delivery systems for therapeutic biomacromolecules.

Nanocomposites comprised of insulated magnetic single-domain particles are promising candidates for high-frequency, eddy current free, soft magnetic materials, but tend to suffer from low magnetic susceptibility (<20). Particle alignment has been proposed to increase nanocomposite susceptibility and reduce magnetic losses but experimental verification has been lacking. Here, magnetic nanocomposites containing 3-57 vol% field-aligned 11±3 nm maghemite particles in a poly-vinyl matrix were investigated for potential use as high-frequency inductor core materials. The particles were aligned by a homogenous static alignment field during nanocomposite drying, fixating the particle orientation. Particle aggregation was disproved by small-angle scattering. The dependence of the alignment field strength and particle concentration on the nanocomposite's susceptibility and hysteresis losses were investigated from DC up to 922 kHz by vibrating sample magnetometry, AC-susceptibility and high-frequency hysteresis measurements. Nanocomposite susceptibility increased super-linearly with particle fraction due to weak particle interactions. Alignment of the particles increased the nanocomposite susceptibility from 21 to 50 for samples with a particle content of 57 vol%. Hence, the synergy between particle alignment and interaction allows for a higher than expected susceptibility of nanocomposites. The results show that magnetically aligning particles in a nanocomposite reduces magnetic losses when using well-dispersed single-domain superparamagnetic nanoparticles. Measured nanocomposite susceptibility could be modelled by a combination of directional dependent Debye-models including mean-field interaction effects and partial particle alignment. Measured susceptibility of 50 is among the highest obtained for nanocomposites, making it a relevant candidate for applications in power electronics.

Thorium and uranium found in polluted water and soil caused by mining are ‌posing ecological security risks and being detrimental to sustainable development of the nuclear energy. Reported chemical sensors exhibit excellent response to uranium or thorium, but most of them only capable of detecting one type of the two nuclide ions in organic solvents or in aqueous organic solvent mixture. So it is still a challenging journey to detect the two nuclides distinctly by a same probe in pure water, especially in the presence of coexisting lanthanide interfering ions. In this work, sequential fluorescence detection of Th4+ and UO22+ in nearly 100% water (H2O/DMSO = 100/1, v/v) is achieved by a fluorescent probe, N′-(pyren-1-ylmethylene)-4-hydroxybenzohydrazide (POH), with the assistance of cationic surfactant cetyltrimethylammonium bromide (CTAB). POH exhibited a distinct green fluorescence toward Th4+ in CTAB aqueous solution, and the detection limit can reach 60.2 nM with a binding constant of 7.07 × 104 M−1. Moreover, the CTAB-POH-Th4+ system presented a selective “turn-off” phenomenon for UO22+ with a high immunity to other interference ions. The detection limit of 88.1 nM toward UO22+ can be reached, with an association constant of 8.17 × 104 M−1. 1H NMR and FT-IR spectroscopic analysis coupled with nuclide ion titration investigations demonstrated that the presence of CTAB facilitated the formation of POH-Th4+ excimer, while the addition of UO22+ replaced the Th4+, leading to specific emission quenching of the excimer, which was supported by DFT calculations. This study provides a reliable sensing strategy for the sequential detection of Th4+ and UO22+ in water. It also offers valuable insights into surfactant-assisted sensing mechanism. The probe-CTAB platform also demonstrates the practical applicability to detect the two nuclides in real water samples.

Mesoporous silica nanoparticles have been synthesized through sol–gel synthesis in basic conditions. Gemini surfactants having urea in the headgroups were used as pore-forming agents. The effect of the spacer length of the surfactant on the particle morphology was studied on the sub-micrometer and nanometer scales using nitrogen porosimetry, small-angle X-ray scattering (SAXS), ultra-small-angle neutron scattering, and scanning and transmission electron microscopy (SEM, TEM). Depending on the spacer, spherical and/or cylindrical nanoparticles formed in different proportions, as revealed by statistical analysis of SEM micrographs. All prepared materials showed the hexagonal pore structure characteristic of the MCM-41 molecular sieves, with the exception of the sample prepared using the gemini surfactant with the shortest spacer length. The influence of the spacer length on the lattice parameter of the pore network, as well as the average size of the ordered domains, has been assessed by SAXS and TEM. Detailed analysis of the TEM images revealed a spread of the lattice parameter in a range of 10–20%. The broadening of the diffraction peaks was shown to be due to the combination of the effects of the finite domain size and the variance of the lattice parameter across the crystalline domains. The structural differences between the silica gels synthesized with the different surfactants were related to the variation of the micelle morphologies, reported in previous light scattering and small-angle scattering experiments. No connection could be revealed between the micelle shape and size and the pore sizes, showing that surfactants with a broad range of spacer lengths can equally well be used for the preparation of MCM-41 materials.

We here present printable and castable magnetic nanocomposites containing superparamagnetic 11±3 nm γ-Fe_2O_3 particles in an insulating poly-vinyl alcohol polymer matrix. The nanocomposites feature well-dispersed particles with volume fractions between 10 and 45 %, as confirmed by small-angle neutron scattering. The magnetic volume susceptibility is as high as 17, together with negligible hysteresis at low frequency, and constant AC-response up to the high-kHz range. Measured hysteresis curves at 100-900 kHz with up to 110 mT induced B-fields in the nanocomposite show that power losses depend on B-field squared, and frequency to the power of 1-1.3. The only loss mechanism in the nanocomposite is hysteresis losses at >100 kHz frequencies, where the largest particles in the 11±3 nm distribution transition from the superparamagnetic to blocked regime. To mitigate the resulting hysteresis losses (up 10^2-10^5 kW/m^3) a more narrow particle size distribution could be used for future materials. The presented material is eddy current-free and easily integrated into micro-fabrication protocols, as we demonstrate by fabrication of 3-turn print circuit board based inductors with cast/manual printed nanocomposite inductor cores, on which induction has been measured up to 100 MHz.

Mesoporous silica sieves have been prepared through sol-gel synthesis using diester gemini surfactants as pore templates, aiming to obtain new materials with potential use for water remediation. A series of mesoporous spherical silica particles of submicron size have been prepared in an alkali-catalyzed reaction, using a tetraethyl orthosilicate precursor and bis-quaternary ammonium gemini surfactants with diester spacers of varied lengths as pore-forming agents. The effect of the spacer length on the particle morphology was studied using nitrogen porosimetry, small-angle X-ray scattering (SAXS), ultra-small-angle neutron scattering, scanning, and transmission electron microscopy (SEM, TEM). The results revealed that for all spacer lengths, a long-range hexagonal pore ordering developed in the materials. The silica particles were nearly spherical, with sizes below 1 micrometer, and a weak dependence of the mean particle size on the spacer length could be observed. The template removal procedure had a strong influence on the porosity: calcination caused a moderate shrinkage of the pores while retaining the hexagonal structure, whereas treatment with acidified ethanol resulted in only partial removal of the surfactants; however, the hexagonal structure was severely destroyed. The applicability of the obtained calcined materials as adsorbents for heavy metal ions from water was studied with the example of Pb(II). A high sorption capacity of 110 mg/g was obtained in batch experiments, at pH 5 and 4 h contact time.

In this work, small angle neutron scattering (SANS) data of branched polyethyleneimine (bPEI)/TEMPO-oxidized and ultrasonicated cellulose nanofiber (TOUS-CNF) xerogels, namely cellulose nano-sponges (CNSs), at different hydration level (h) and cross-linker amount, were analyzed through a combined approach involving generalized (2DCOS) and perturbation-correlation moving window (PCMW2D) two-dimensional correlation spectroscopy. The aim was to get novel insights into the sequence of structural changes experienced by the xerogel moieties upon hydration, based on the assessment of the cross-correlations existing at different length scales retrieved by the synchronous (SCMs) and asynchronous (ACMs) 2DCOS and PCMW2D correlation maps calculated upon variation in the chosen perturbation variable. It is worth noting that the application of 2DCOS and PCMW2D on SANS data enabled the identification of structural transitions that are not readily apparent from conventional SANS analysis, highlighting the sensitivity of this method in detecting structural dynamics as well as any minor changes in the polymer arrangement at both low and high spatial scales.

Water pollution caused by antibiotic effluents, particularly ciprofloxacin is a growing environmental concern. To address this problem, silica aerogels containing vinyl, epoxide, or methacrylate organic functionalities were synthesized through facile sol-gel synthesis under ambient conditions and employed as ciprofloxacin adsorbents in this study. The physicochemical and structural features of the materials were characterized using conventional and complementary techniques. Structural characterization confirmed the successful chemical functionalization of the silica surface for all samples. Similar to the pristine aerogel, the vinyl-functionalized aerogel displayed a typical mesoporous network, whereas epoxide and methacrylate functionalization caused dominantly macroporous structures. Batchwise sorption experiments were performed under different operating conditions. The results of the equilibrium and kinetic adsorption studies showed excellent alignment with the Langmuir isotherm and pseudo-second-order kinetic models, respectively. Under optimum conditions (C0 = 100 mg/L, mads/Vsoln = 0.5, pH=6, t = 90 min), the adsorption capacities of ciprofloxacin onto vinyl, epoxide, and methacrylatemodified aerogels were 62.7, 45.8 and 47.8 mg/g, respectively. Despite of the differences at micro- meso- and macrostructure level, obtaining similar adsorptive performances confirms that mechanism of sorption is not only relied on pore filling but also controlled by molecular interactions. The adsorbents also exhibited repetable sorption performance for at least six cycles.

This study investigated the effects of solvent vapor annealing on the microphase separation structure of polyurethane (PU) using small-angle X-ray scattering (SAXS) and complementary techniques. Solvent annealing, as an alternative to thermal annealing, offers a lower-temperature method to refine the microstructure of PU. We examined the impact of methyl ethyl ketone (MEK), acetone and toluene vapors on a commercial polyether PU, focusing on changes in microphase structure, adsorption kinetics and thermal stability. The SAXS data, analyzed by a polydisperse hard-sphere model, indicated that the degree of phase separation increased upon solvent annealing, and the order of influence exerted by the solvent vapors on the microphase structure follows MEK > acetone > toluene. The in situ variable-temperature SAXS results showed that the solvent-annealed sample had superior thermal stability to the quenched sample. Compared with high-temperature annealing, solvent annealing induced a higher degree of phase separation but did not lead to significant growth of the hard-urethane-segment-rich domains. These findings provide valuable insights into optimizing solvent annealing processes, allowing for advanced applications of PUs where excessive heat may lead to degradation or other undesirable changes.

An Erratum to this paper has been published: https://doi.org/10.1134/S0031918X24120044

Thorium is a notable candidate for resolving uranium shortage caused by the global application of nuclear power generation. Uranium extraction from seawater is another attempt to handle its source deficiency, however, vanadium is one of the main competitive elements in that process. Exploration of probes which can discriminatively detect thorium and vanadium from uranium has primary significance for their further separation and for environmental protection. Herein, N′-(2,4-dihydroxybenzylidene)-4-hydroxylphenylhydrazide, AOH, is used as sensor for Th4+ and vanadyl (VO2+) determination. AOH demonstrates a specific “turn-on” fluorescence selectivity towards Th4+ over f-block and other foreign metal ions, with a detection limit (LOD) of 7.19 nM in acidic solution and a binding constant of 9.97 × 109 M−2. Meanwhile, it shows a “turn-off” fluorescence response towards VO2+ over other metal ions at the coexistence of Th4+, with a LOD of 0.386 μM in the same media and a binding constant of 4.54 × 104 M−1. The recognition mechanism, based on HRMS, 1H NMR, and FT-IR results, demonstrates that VO2+ causes the fluorescence quenching by replacing Th4+ to coordinate with AOH. In real water detection tests, Th4+ and VO2+ exhibited satisfying recoveries. These findings expand the application of sensors in nuclide pollution control.

The characterization of the structure of ferritin in solution and the arrangement of iron stored in its cavity are intriguing subjects for both cell biology and applied science, since the protein structure, stability, and easiness of production make it an ideal tool for biomedical applications. We characterized the ferritin structure over a wide range of iron loadings by visible light, X-ray, and neutron scattering techniques. We found that the arrangement of iron ions inside the protein cage resulted in a more disposable arrangement at lower loading factors and then in a crystalline structure. At very high iron content the inner core is composed of magnetite more than ferrihydrite, and the shell of the protein is elastically deformed by the iron crystal growth in an ellipsoidal arrangement. The application of an external radiofrequency (RF) magnetic field affected ferritins at low iron loading factors. Notably the RF modified the iron disposition towards a more dispersed arrangement. The structural characterization of the ferritin at different LFs and in presence of magnetic fields provides useful insights into their physiological behaviour and can help in the design and fine-tuning of ferritin-based nanosystems for biotechnological applications.

Presented here is an effective approach to desmearing slit ultra-small-angle neutron scattering (USANS) data, based on complementary small-angle neutron scattering (SANS) measurements, leading to a seamless merging of these data sets. The study focuses on the methodological aspects of desmearing USANS data, which can then be presented in the conventional manner of SANS, enabling a broader pool of data analysis methods. The key innovation lies in the use of smeared SANS data for extrapolating slit USANS, offering a self-consistent integrand function for desmearing with Lake's iterative method. The proposed approach is validated through experimental data on porous anodized aluminium oxide membranes, showcasing its applicability and benefits. The findings emphasize the importance of accurate desmearing for merging USANS and SANS data in the crossover q region, which is particularly crucial for complex scattering patterns.

Mesoporous materials containing heteroelements have a huge potential for use as catalysts, exchangers, and adsorbents due to their tunable nanometer-sized pores and exceptionally large internal surfaces accessible to bulky organic molecules. In the present work, ordered mesoporous silica containing Ni atoms as active sites was synthesized by a new low-temperature method of condensation of silica precursors on a micellar template from aqueous solutions in the presence of nickel salt. The homogeneity of the resulting product was achieved by introducing ammonia and ammonium salt as a buffer to maintain a constant pH value. The obtained materials were characterized by nitrogen sorption, X-ray and neutron diffraction, scanning electron microscopy, infrared spectroscopy, and thermal analysis. Their morphology consists of polydisperse spherical particles 50–300 nm in size, with a hexagonally ordered channel structure, high specific surface area (ABET = 900–1200 m2/g), large pore volume (Vp = 0.70–0.90 cm3/g), average mesopore diameter of about 3 nm, and narrow pore size distribution. Adsorption tests for methylene blue show sorption capacities reaching 39–42 mg/g at alkaline pH. The advantages of producing nickel silicates by this method, in contrast to precipitation from silicon alkoxides, are the low cost of reagents, fire safety, room-temperature processing, and the absence of specific problems associated with the use of ethanol as a solvent, as well as the absence of the inevitable capture of organic matter in the precipitation process.

We report how the solution structure, beta-conformation and film morphology develop in poly(9,9-dioctylfluorene) (PFO) solutions and suspensions, as well as in subsequently prepared films when the molecular weight and solvent quality are systematically varied in toluene-acetone mixtures. The polymer series with molecular weights ranging from 10 kDa to 100 kDa is prepared using the precipitation fraction. The beta conformation is favored by increasing molecular weight (>= 30 kDa) and decreasing solvent quality (>= 45 % acetone content). The content of the beta conformation in the films is significantly increased when the beta conformation already exists in precursor suspensions. In contrast, when there is no beta conformation in the precursor solution, no beta conformation will appear in the films. The mechanisms of phenomenological transformation are discussed. This work is a step toward developing quantitative guidelines for controlling PFO solutions and their film properties.

Nanostructures of a wide range of oxide dispersion strengthened (ODS) steels are characterized using small-angle X-ray scattering (SAXS). The systems of alloying of the studied steels differ in the content of Cr, V, Ti, Al, and Zr. It is shown that the use of SAXS makes it possible to determine the number density of nanosized inclusions in ODS steels and their size distribution.

Recent advancements in nanotechnology have led to the development of multifunctional iron oxide nanoparticles, presenting new opportunities in cancer therapy. This study aimed to synthesize and evaluate citric acid-coated/ folic acid conjugated nanoparticles loaded with doxorubi-cin and investigate their efficacy in experimental tumor models. For synthesis, controlled co-precipitation method was employed to produce highly dispersive, multifunctional nanofluids with a narrow size distribution of iron oxide nanoparticles. Nanoparticles were characterized using Dynamic Light Scattering (DLS) and Electrophoretic Light Scattering (ELS) for size distribution and zeta potential, X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) for structure and morphology, Vibrating Sample Magnetometry (VSM) for magnetic properties, and UV-Visible (UV-Vis) and Fourier-Transform Infra-red (FTIR) spectroscopy for modification confirmation. In vitro experiments employed RM1 (prostate cancer) and MEC1 (Chronic lymphocytic leukemia) cell lines to assess cytotoxicity and drug delivery efficiency. Fluorescence microscopy confirmed the intracellular delivery of doxorubicin by these nanoparticles, highlighting their potential for targeted therapy. As a result, nanoparticles conjugated with folic acid showed reduced efficacy over time. This study underscores the critical role of nanoparticle modifications in optimizing therapeutic outcomes. Future research should focus on further refining nanoparticle formulations and long-term effects in vivo, for development of effective and safe agents for targeted cancer treatment.