One-step Dissolution Research Articles

Processing the Interlayer and Optimizing the Active Layer by One-Step Dissolution Compensation in Organic Solar Cells.

Optimized morphology of the active layer and electrode interface is critical for obtaining high-performance organic solar cells. However, achieving this typically involves a multifaceted, sequential process that renders outcomes unpredictable. Here, by exploiting the dissolution compensation, we propose a one-step method that integrates interlayer fabrication and a controllable morphology optimization. Taking an "out of the box" approach, we incorporate the good solvent of the active layer into the interlayer solution to act as dissolution compensation, breaking the orthogonal solvent principles to allow the morphology of the active layer to evolve to an optimized state while the interface layer is being processed. Using two commercially available material systems, D18:Y6 and D18:L8-BO, as examples, it was found that the JSC and fill factor (FF) device can be improved by using an appropriate ratio of the compensation solvent chloroform in the interlayer solution. As a result, the power conversion efficiency of the device based on the two state-of-the-art systems can be increased by about 7.5% (D18:Y6, from 17.04 to 18.31%; D18:L8-BO, from 17.97 to 19.31%). This one-step strategy has been shown to be universally applicable to other diverse systems and provides a simple yet reliable method for accurately depositing high-quality interlayers with an optimized active layer morphology in high-performance organic solar cells and other solution-processable organic electronics.

Citric acid/chitosan adhesive with viscosity-controlled for wood bonding through supramolecular self-assembly

Developing bio-based sustainable wood adhesives is significant as a substitute for petroleum-derived adhesives. However, the existing bio-based adhesives have disadvantages of complex fabrication, uncontrollable viscosity, and poor water resistance. Herein, we developed a citric acid/chitosan adhesive with viscosity-controlled and water-resistant features by one-step dissolution at room temperature based on the supramolecular self-assembly strategy. Different wood products (plywood, laminated veneer lumber and particleboard) with superior performance were prepared by applying that adhesive on veneer and wood particles (fine and rough particles). The plywood test results showed that the citric acid/chitosan adhesive had dry and wet shear strengths outperforming the China National Standard (GB/T 9846-2015, ≥0.7 MPa), reaching 2.1 and 1.1 MPa, respectively. The adhesion mechanism was mechanical interlocks and cross-linking of citric acid/chitosan in adhesives with those in the cell wall. This work provides high promise for alternatives to traditional unsustainable wood adhesives (urea-formaldehyde, melamine-urea-formaldehyde and phenolic resins) for fabricating different wood products.

Design and Evaluation of Two-Step Biorelevant Dissolution Methods for Docetaxel Oral Formulations.

Dissolution is a pivotal tool for oral formulations. Dissolution could be used to either reduce the risk of product failure through quality control or predict and understand in vivo performance of drug formulations. The latter is always challenging because multiple factors such as selection of media, gastrointestinal components, physiological factors, consideration of fasted and fed state are involved. Previously published dissolution methods such as one-step dissolution in individual simulated gastric fluid, simulated intestinal fluid, or phosphate buffer saline did not signify the realistic gastrointestinal transit effect. Docetaxel (DTX), a poorly water-soluble drug, is commercially available only as injectable dosage forms, and thus many publications studied the development of oral DTX formulations. In our previous report, we developed oral lipid-based DTX granules that showed higher oral absorption in rats compared to DTX powder. However, one-step dissolution in simulated gastric fluid showed no difference between DTX granules and DTX powder. Therefore, the present study aimed to develop new two-step biorelevant dissolution methods for DTX oral formulations. In the study, new two-step biorelevant dissolution methods in fasted or fed states with pancreatin were developed and compared with other previously reported dissolution methods. The new two-step biorelevant dissolution methods successfully discriminated the difference of dissolution between DTX granules and DTX powder, which reflected the in vivo difference of absorption of these two formulations. Moreover, food effects were confirmed for DTX. The new dissolution methods have the potential to be used to predict and understand in vivo performance of oral solid dosage forms.

Multifunctional chitin-based barrier membrane with antibacterial and osteogenic activities for the treatment of periodontal disease

The guided tissue regeneration technique is an effective approach to repair periodontal defect. However, collagen barrier membranes used clinically lose stability easily, leading to soft tissue invasion, surgical site infection, and failure of osteogenesis. An ideal barrier membrane should possess proper antibacterial, osteoconductive activities, and favorable biodegradation. In this study, zinc oxide nanoparticles were homogeneously incorporated into the chitin hydrogel (ChT-1%ZnO) through one-step dissolution and regeneration method from alkaline/urea solution the first time. The remaining weights of ChT-1%ZnO in 150 μg/mL lysozyme solution was 52% after 5 weeks soaking. ChT-1%ZnO showed statistical antibacterial activities for P. gingivalis and S. aureus at 6 h, 12 h, and 24 h. Moreover, ChT-1%ZnO exhibits osteogenesis promotion in vitro, and it was further evaluated with rat periodontal defect model in vivo. The cemento-enamel junction value in ChT-1%ZnO group is 1.608 mm, presenting a statistical difference compared with no-membrane (1.825 mm) and ChT group (1.685 mm) after 8 weeks postoperatively.

A facile approach for preparation of PSt@TiO2 navel-like hollow Janus particles and its enhanced UV absorption performance

With anisotropic particles attracting much attention for both theoretical and practical application considerations, it was critical to simply manufacture the special morphology particles with different structure or/and surface chemistry. Herein, a novel one-step dissolution template method was described to prepare PSt@TiO2 (Polystyrene @ Titania) navel-like hollow Janus particles (NHJPs). These NHJPs could be obtained simply with dissolution of sulfonated-PSt core template only by regulating the volume ratio of tetrahydrofuran-ethanol solution. The morphologies of these particles were characterized by SEM and TEM. The FT-IR, XPS, XRD and TGA were performed to determine the composition. The formation mechanism of NHJPs was also studied, and the morphology could be control by regulating the dissolution time and the solubility parameters of solvent. The NHJPs showed excellent ultraviolet absorption and the band gap of NHJPs was obtained by UVDRS, which was further proved their highly attractive for photocatalytic materials. Moreover, the preparation method of the PSt@TiO2 NHJPs presented here was scalable and can be extended to other similar systems.

One-step synthesis of SnO hierarchical architectures under room temperature and their photocatalytic properties

Three-dimensional (3D) SnO hierarchical architectures were synthesized via a one-step dissolution–precipitation route under room temperature using SnCl2 · 2H2O and Na2CO3 as the initial reagents. The morphology and size of the prepared SnO structures could be easily tailored by alternating the solvent from deionized water with absolute ethanol. The SEM observation showed that the prepared 3D SnO hierarchical architectures consisted of nanosheets. The size of the SnO hierarchical architectures could be effectively reduced from 4–10 μm to 1–2 μm when the solvent was changed from water to ethanol while the thickness of the assembling nanosheets was reduced from 200–500 nm to 20–30 nm at the same time. The possible formation mechanism of the 3D SnO hierarchical architectures is proposed in this paper. The photodegradation of methylene blue revealed that the SnO hierarchical structures prepared using ethanol as the solvent exhibit much better photocatalytic activity due to its smaller particle size, larger specific surface area, and appropriate band structure as well.

Dissolution kinetics of fluorapatite in the hydrochloric acid solution

A thermochemical study of hydrochloric acid attack of synthetic fluorapatite was performed by a DRC. The calculated thermogenesis curves show one peak. The plot of the heat quantity as a function of the dissolved mass undergoes only one straight segment, and the thermogenesis curves present a single peak, suggesting the occurrence of a one-step dissolution process. The dissolution kinetics was examined according to the heterogeneous reaction models and showed that the dissolution is controlled by the product layer diffusion process with a reaction rate expressed by the following semiempirical equation; \(\left[ {1 + 2(1 - X) - 3(1 - X)^{{\frac{2}{3}}} } \right] = 3195 \times 10^{ - 2} C^{0.145} \left( {\frac{S}{L}} \right)^{ - 0.628} e^{{ - \frac{2600}{\text T}}} t\). The activation energy was determined as 21.6 ± 1.5 kJ mol−1

Dissolution and hydrolysis of fibre sludge using hydroxyalkylimidazolium hydrogensulphate ionic liquids

The dissolution and hydrolysis of wet fibre sludge in ionic liquids (ILs) with different reaction conditions are performed in this study. Novel types of hydroxyalkylimidazolium hydrogensulphate ILs, [glymim]HSO4, [hemim]HSO4 and [hpmim]HSO4, are especially designed and aimed to combine the dissolution and hydrolysis of wet fibre sludge in a one-step pretreatment. The results were obtained based on the analysis of total reducing sugars (TRS) with the DNS method. The dissolution and hydrolysis of fresh wild horse chestnut fruit (Aesculus hippocastanum) with the same ILs were also carried out as a comparison reference. Since fibre sludge is cellulose based and horse chestnut fruit is starch based, a direct comparison of the difference in functions between these ILs in one-step dissolution and hydrolysis were analysed based on the results.

Task-specific ionic liquid [SBMIM]Cl in one-step dissolution and hydrolysis of fibre sludge

Fibre sludge is a cellulose-rich by-product obtained from the chemical pulping process of wood chips. In this study, a one-step pretreatment procedure is considered in which fibre sludge can be simultaneously dissolved and depolymerised in an ionic liquid media. Task-specific ionic liquid (TSIL), i.e. 1-(4-sulfonylbutyl)-3-methylimidazolium chloride [SBMIM]Cl, is used as an ionic liquid media.Based on the results, [SBMIM]Cl has the ability to dissolve and hydrolyse fibre sludge in a one-step reaction. Yields of total reducing sugars (TRS) after [SBMIM]Cl pretreatment were not high (a mass fraction around 4–5%), but still comparable to yields of TRS after acid hydrolysis (a mass fraction between 2 and 8%). Furthermore, [SBMIM]Cl is able to dissolve and depolymerise both dry and wet material even up to a moisture mass fraction of 50%, which is a significant advantage when wet fibre sludge is used as a raw material.

Determination of melatonin in commercial preparations by micellar electrokinetic chromatography and spectrofluorimetry

Melatonin was determined in pharmaceutical preparations by means of two simple and reliable analytical methods based on micellar electrokinetic chromatography (MEKC) and spectrofluorimetry. The fluorescence emission values were measured at λ=350 nm when exciting at λ=275 nm. The MEKC analysis was achieved using a system consisting of 40 mM SDS in phosphate buffer (20 mM, pH 7.5). The extraction of melatonin from the tablets was achieved by means of a simple one-step dissolution with methanol/water. Both methods were applied for the determination of melatonin in commercial formulations and galenic preparations. The MEKC procedure allows the quantitative determination of melatonin in all pharmaceutical preparations tested. On the contrary, the spectrofluorimetric method is not suitable for tablets which also contain tryptophan; this interference can be eliminated by a suitable liquid–liquid extraction procedure. The results obtained with the two methods are in good agreement and satisfactory in terms of precision and accuracy.

Rapid methods for determination of fluoxetine in pharmaceutical formulations

Two different analytical methods for the quality control of fluoxetine in commercial formulations have been developed and compared: a spectrofluorimetric method and a capillary zone electrophoretic (CZE) method. The fluorescence emission values were measured at λ=293 nm when exciting at λ=230 nm. The CZE method used an uncoated fused-silica capillary and pH 2.5 phosphate buffer as the background electrolyte. The extraction of fluoxetine from the capsules consisted of a simple one-step dissolution with methanol/water, filtration and dilution. Both methods gave satisfactory results in terms of precision; the best results were obtained for the electrophoretic method, with RSD% values always lower than 2.0%. The accuracy was assessed by means of recovery studies, which gave very good results, between 97.5 and 102.6%. Furthermore, both methods also have the advantage of being very rapid.

Study of the initial stage of white rust formation on zinc single crystal by EIS, STM/AFM and SEM/EDS techniques

The kinetic consequences of morphological changes due to the zinc exchange process have been related to the corrosion performance and a further understanding of the initial stage of the white rust formation occurring preferentially in a thin layer of moisture in the absence of oxygen. Electrochemical impedance diagrams for a uniformly covered Zn corrosion product layer can be interpreted by a one-step dissolution mechanism, while on a non-uniform, partially active surface a consecutive dissolution occurs via adsorbed Zn(I) and Zn(II) species. The in situ EC-STM and EC-AFM observations revealed oriented Zn dissolution, deposition along the atomic steps and oriented oxide formation on the redeposited crystal planes in the early stages of each process.

Desorption of Amphotericin B from Mixed Monolayers with Cholesterol at the Air/Water Interface

The desorption of amphotericin B (AmB) from mixed monolayers with cholesterol was studied by monitoring temporal changes in the relative area (At/A0) as a function of time at constant surface pressures, corresponding to three distinct regions of the AmB isotherm. The loss of AmB molecules from the interface was found to obey the Ter Minassian Saraga model [J. Colloid Interface Sci.11, 398 (1956)]. In the low surface pressure region the overall process of desorption is controlled by a one-step dissolution (at small times) followed by diffusion. At high pressures, however, the process of dissolution is more complex and consists of two steps that differ in rate. The presence of cholesterol molecules in the monolayer prevents the desorption of AmB molecules as evidenced by the constant desorption values. The analysis of the kinetics parameters confirms our previous findings, based on the analysis of excess functions, that the highest interactions, due to the stable complex formation, appear for the mixture of XAmB=0.7.

Pitting and Stress Corrosions of Aluminum Alloys; Correlation between Them

It is found that pitting corrosion evolves solely in solutions bearing monovalent anions. This fact is associated with the specific features of one-step dissolution. The pitting corrosion of aluminum typically evolves over its (100) crystallographic planes. Such crystallographic type of corrosion gives way to other types with an increase in the pitting initiation potential and the content of alloying elements. The obtained curves for the pitting initiation potential as a function of the solution strength show regions of passivity, a linear dependence, and the transition to the value of the pitting initiation potential measured in pure water. Common features in pitting and stress corrosions evolving from passive state are revealed. However, for stress corrosion, the factors which accelerate depassivation are dislocation piles-up at grain boundaries and hydrogen, which arises by corrosion reactions and weakens intergranular bonds. Under conditions when pitting corrosion shows up as local tunnels directed toward phase inclusions, transgranular corrosion cracking is observed; whereas, under conditions when pitting corrosion evolves on grain boundaries, intergranular cracking is observed.

The Corrosion of Bivalent Transition Metals in Acid Media Under Polarization

Abstract The initial and the steady-state expressions of the current density and of the degrees of coverage with adsorbed atomic and molecular hydrogen under potentiostatic conditions have been studied, assuming a one-step dissolution of a bivalent metal and an electrochemical desorption mechanism or hydrogen evolution. At 25°C, the anodic slope Δη/Δ log i for metal dissolution ranges between 19.5 and 59 mV for the steady state and between 59 and 118 for the initial moment of polarization, depending on the ratios between the chemical rate constants of the reaction concerned. As a function of these ratios, of the pH and the anodic overvoltage, the initial current can be higher than, equal to, or smaller than the steady-state current.