Phase Inversion Research Articles

Polymer‐Sorbent Direct Air Capture Contactors with Complex Geometries 3D‐Printed via Templated Phase Inversion

AbstractLow‐cost direct air capture (DAC) systems require efficient gas–solid contactors. These contactors provide rapid rates of heat and mass transport with minimal pressure drops. Triply periodic minimal surfaces (TPMS) are a class of geometries that are shown to have heat transfer properties that exceed those of other geometries, and these benefits are expected to manifest in mass transfer as well due to the analogies between heat and mass transfer. However, creating TPMS contactors is difficult using conventional manufacturing techniques such as injection molding. Non‐solvent‐induced phase separation (NIPS) of a polymeric ink containing the adsorbent is one way to construct adsorption contactors with excellent mass transport rates, but contactors have to date only been fabricated in simple geometries (e.g., films, fibers). This study demonstrates that NIPS of polymeric inks occurs within a simultaneously‐dissolving, water‐soluble, 3D‐printed template. This templated phase inversion (TPI) technique can create seemingly unlimited macroscopic architectures, including TPMS contactors, using a variety of potential DAC adsorbents, including zeolite, silica, activated carbon, and metal–organic frameworks. SEM, micro‐computed tomography, and nitrogen adsorption experiments reveal the microscopic pore structures and macroscopic geometries of the resulting sorbent contactors. TPMS DAC contactors with poly(ethyleneimine)/silica adsorbents are shown to have CO2 capture performances that rival or exceed other contactor geometries.

Lithium Chloride-Mediated enhancement of dye removal capacity in Borneo bamboo derived nanocellulose-based nanocomposite membranes (NCMs)

Demand for sustainable materials for membrane fabrication is rapidly increasing, particularly in Sarawak coastal areas. nanocellulose emerges as a promising alternative for membrane development due to its availability, intrinsic biodegradability, and high strength. However, the hydrophobicity of nanocellulose limits its applicability in water treatment operations. Hence necessitating the need for innovative solutions. Herein, we examine the potential of bamboo-derived nanocellulose to enhance nanocomposite membrane-based water treatment systems by incorporating lithium chloride as a pore-forming additive. Nanocomposite membranes (NCMs) were synthesised using a LiCl-doped solution of nanocellulose and polyvinylidene fluoride (PVDF) through phase inversion and controlled solidification methods. The results show that nanocellulose incorporation induces structural alterations in NCMs, with reduced size in cellulose microfibrils. The crystallinity of nanocellulose was enhanced through interactions between PVDF and nanocellulose. The integration of nanocellulose along with lithium chloride was observed to have a significant impact on water permeation flux, attaining 104 L/m2h due to improved hydrophobicity and reduced fouling. In addition, the developed NCMs recorded 93 % methylene blue (MB) removal within 10 min. Revealing high potential of NCMs as an alternative and sustainable material for the development of nanocomposite membranes to mitigate contemporary challenges of water scarcity.

Preparation of a high performance PES/PES-OH Loose nanofiltration membrane based on reactive porogen

Loose nanofiltration membranes (LNF) have wide applications in the field of precise separation of small organic molecules. However, high separation precision of organic molecules with salts and a high water flux are still the challenges in the commercial applications of LNF membranes. In the current work, polyethersulfone (PES)/hydroxylated polyethersulfone (PES-OH) LNF membranes were synthesized by nonsolvent-induced phase separation (NIPS) based on reactive porogen (butyl dicarbonate, BDC) for the first time. The reactive porogen was decomposed to produce nanobubbles during heat-treated casting solution and phase inversion in HCl coagulation. It was found that the heat-treatment temperature of the casting solution was higher, the viscosity of the solution at 20 °C was higher due to the existence of more nanobubbles from BDC decomposition in the casting solution. Moreover, heat-treatment temperature had decisive impacts on the structure and separation property of the formed LNF membranes as nanobubbles actually acted as pore-forming agents. The HCl coagulation/immersion baths also promoted the BDC decomposition to produce the nanobubbles and improved the transmembrane water flux without sacrificing rejection and separation precision performance. The synthesized LNF membrane had a pore diameter approximately 3.81 nm, with a flux up to 200.2 L·m−2·h−1. Direct Black 38 shows a rejection of > 99 %, whereas NaCl shows a rejection of < 5 %, exhibiting a good separation accuracy and found superior to the separation performance in the literature. This research result has offered a novel approach for the preparation of superior performance LNF membranes, which can be utilized for precise separation.

Cationic Amphiphilic Comb-Shaped Polymer Emulsifier for Fabricating Avermectin Nanoemulsion with Exceptional Leaf Behaviors and Multidimensional Controlled Release.

The development of intelligent multifunctional nanopesticides featuring enhanced foliage affinity and hierarchical target release is increasingly pivotal in modern agriculture. In this study, a novel cationic amphiphilic comb-shaped polymer, termed PEI-TA, was prepared via a one-step Michael addition between low-molecular-weight biodegradable polyethylenimine (PEI) and tetradecyl acrylate (TA), followed by neutralization with acetic acid. Using the emulsifier PEI-TA, a positively charged avermectin (AVM) nanoemulsion was prepared via a phase inversion emulsification process. Under optimal formulation, the obtained AVM nanoemulsion (defined as AVM@PEI-TA) demonstrated exceptional properties, including small size (as low as 67.6 nm), high encapsulation efficiency (up to 87.96%), and high stability toward shearing, storage, dilution, and UV irradiation. The emulsifier endowed AVM@PEI-TA with a pronounced thixotropy, so that the droplets exhibited no splash and bounce when they were sprayed on the cabbage leaf. Owing to the electrostatic attraction between the emulsifier and the leaf, AVM@PEI-TA showed improved leaf adhesion, better deposition, and higher washing resistance in contrast to both its negatively charged counterpart and AVM emulsifiable concentrate (AVM-EC). Compared to the large-sized particles, the small-sized particles of the AVM nanoemulsion more effectively traveled long distances through the vascular system of veins after entering the leaf apoplast. Moreover, the nanoparticles lost stability when exposed to multidimensional stimuli, including pH, temperature, esterase, and ursolic acid individually or simultaneously, thereby promoting the release of AVM. The release mechanisms were discussed for understanding the important role of the emulsifier in nanopesticides.

Effect of porous irregular ZrO2 nanoparticles on the performance of alkaline water electrolysis composite separator membranes under complex conditions

Developing composite separator membranes with low area resistance, high bubble point pressure, and long-term safety and stability is crucial for alkaline water electrolysis for hydrogen production as a key component of electrolyzer systems. In this study, PPS mesh fabric reinforced PSF@ZrO2 composite separator membranes were successfully prepared using the immersion-drawing phase inversion method, with PSF as the alkali-resistant polymer matrix and porous irregular ZrO2 nanoparticles as the hydrophilic additive. The experimental results showed that replacing commercial ZrO2 with porous irregular ZrO2 nanoparticles at an 85 wt% ZrO2 nanoparticle loading improved both bubble point pressure and current transmission efficiency, attributed to the change in the morphological structure of the ZrO2 nanoparticles. The P-Z85 composite separator membrane exhibited highly promising characteristics, with a high bubble point pressure of 3.76 bar and a low area resistance of 0.20 Ω cm2. Stability tests conducted in 30 wt% KOH electrolyte at 80 °C and a current density of 0.65 A cm−2 demonstrated excellent continuous electrolysis stability for the P-Z85 composite separator membrane. These results indicate that the PSF@ZrO2/PPS composite separator membrane prepared in this study exhibits excellent performance in 30 wt% KOH electrolyte, significantly extending its service life.

Fabrication and evaluation of PVDF membranes modified with cellulose and cellulose esters from peanut (Arachis hypogea L.) shell for application in methylene blue filtration

Polyvinylidene fluoride (PVDF) membrane is frequently employed for filtration due to its excellent properties. The hydrophobicity of PVDF membrane causes easy fouling; therefore, hydrophilic polymer materials are required to increase hydrophilicity. This study applies cellulose and cellulose esters as fillers for PVDF membranes to solve the fouling problem. Cellulose esters, such as cellulose acetate (PSCA), cellulose benzoate (PSCB), and cellulose citrate (PSCC), were successfully synthesized from peanut shell cellulose (PSC) using Fischer and non-Fischer reactions. The phase inversion method was successfully used to fabricate PVDF membranes with cellulose or cellulose esters as fillers. The fabricated membranes have been applied for methylene blue (MB) filtration. Adding PSC fillers improved the hydrophilicity and performance of the PVDF membranes up to 23.49 ± 2.40 L m−2 h−1 for water flux and 95.75 ± 0.78 % for rejection of MB. Regarding cellulose esters, cellulose acetate gave the highest value of 77.63 L m−2 h−1 for water flux, and cellulose citrate gave the highest value of 86.88 ± 3.54 % for MB rejection. Hence, cellulose or cellulose esters from peanut shells are suitable fillers for MB filtration in PVDF membranes.

One-step fabrication of hetero-structured polyethersulfone hollow fiber membranes through surface segregation for pervaporation desalination

Hollow fiber membranes (HFMs) are an ideal configuration for industrial applications of pervaporation desalination (PV) membranes. Currently, the efficient fabrication of PV HFMs is restricted by multi-step post-treatment processes on their outer surfaces to form the selective layer. Herein, we utilized the surface segregation strategy to fabricate a hetero-structured HFM in one step, simultaneously forming the hydrophilic dense outer layer and the porous support layer. During hollow fiber spinning process, the amphiphilic copolymer polyvinylpyrrolidone-polyvinyl acetate (PVP-PVAc) in polyether sulfone (PES) dope solution migrated towards water contacting interface in the coagulation bath and formed the hydrophilic layer by extending hydrophilic segment outwards. This fast in-situ hydrophilization well matched the spinning efficiency. The optimal PVP-PVAc content and phase inversion temperature were investigated and the spinning parameters on the structure and performance of HFMs were studied. The HFMs prepared realized a flux of 26.70 kg m−2 h−1 and the salt rejection of 99.98 %, along with adaptability to solutions with different salinities and excellent anti-organic fouling property. This study may provide a facile method to fabricate HFMs with desirable PV desalination performance and scaling-up potential.

Formulation, characterization, and stability of morin hydrate-loaded nanoemulsion

Morin hydrate (MH) is a bioflavonoid belonging to flavonol class. Despite its pharmacological activities, MH has inherent low aqueous solubility and chemical instability hindering biological applications of this flavonol. In this regard, this study aimed to develop and characterize nanoemulsion containing MH. Nanoemulsion formulations were prepared using phase inversion temperature method and characterized by size, polydispersity index (PdI), physical stability, AFM analysis, incorporation efficiency (IE), and in vitro release. Following the formulation design, F10 formulation was chosen to incorporate MH. Nanoemulsion containing MH (MH-NE) showed droplet size in nanometric scale (< 100 nm) with homogeneous size distribution (PdI < 0.1). In addition, good physical stability of MH-NE was demonstrated using analytical photocentrifugation method where the light transmission profiles did not change throughout the emulsions. According to AFM analysis, oil droplets were mostly spherical or semi-spherical having sizes uniformly distributed. The IE of MH into nanoemulsion was approximately 100%, and in vitro release profile of this flavonol from formulation was gradual throughout the experiment. Therefore, using a reproducible method of low energy emulsification we developed a stable colloidal dispersion of nanoemulsion containing MH.

Synthesis and Physicochemical Stability of a Copaiba Balsam Oil (Copaifera sp.) Nanoemulsion and Prospecting of Toxicological Effects on the Nematode Caenorhabditis elegans.

Nanoemulsions are dispersions of oil-in-water (O/W) and water-in-oil (W/O) immiscible liquids. Thus, our main goal was to formulate a nanoemulsion with low surfactant concentrations and outstanding stability using Copaiba balsam oil (Copaifera sp.). The high-energy cavitation homogenization with low Tween 80 levels was employed. Then, electrophoretic and physical mobility properties were assessed, in addition to a one- and two-year physicochemical characterization studies assessment. Copaiba balsam oil and nanoemulsions obtained caryophyllene as a major constituent. The nanoemulsions stored at 4 ± 2 °C exhibited better physical stability. Two years after formulation, the nanoemulsion showed a reduction in the particle size. The size underwent changes in gastric, intestinal, and blood pH, and the PdI was not changed. In FTIR, characteristic bands of sesquiterpenes and overlapping bands were detected. When subjected to freezing and heating cycles, nanoemulsions did not show macroscopic changes in higher concentrations. Nanoemulsions subjected to centrifuge force by 1000 rpm do not show macroscopic instability and phase inversion or destabilization characteristics when diluted. Therefore, the nanoemulsion showed stability for long-term storage. The nematode Caenorhabditis elegans was used to assess the potential toxicity of nanoemulsions. The nanoemulsion did not cause toxicity in the animal model, except in the highest concentration tested, which decreased the defecation cycle interval and body length. The toxicity and stability outcomes reinforce the nanoemulsions' potential for future studies to explore pharmacological mechanisms in superior experimental designs.

Chemical characterization and biotechnological potential of Salvia rosmarinus Spenn essential oil nanoemulsions

This study aimed to determine the total phenolic compounds, evaluate the antioxidant and antiinflammatory activities of nanoemulsions (O/W) and essential oils (EOs) from Salvia rosmarinus (rosemary). The plant material was obtained in the city of São Luís (MA). The EO was obtained by the hydrodistillation technique in a modified Clevenger extractor, and the NOE’s by phase inversion. The chemical constituents of EO were determined by GC-MS. The determination of total phenolic compounds (TPC) was performed by the Folin-Ciocalteu method. The anti-inflammatory activity was performed by the method of protein denaturation, and the antioxidant activity was performed by the spectrophotometric method of scavenging hydroxyl radicals. The GC-MS allowed quantifying 1,8-cineol (30.22%), α-pinene (22.14%), camphor (18.33%), and camphene (10.36%) as major components of the EO. The TPC of the EO was quantified at 26.74 mg EAT g-1 and the refractive index at 1.466 nD 25°. In the antioxidant activity test, an EC50 of 80.33 mgL-1 was obtained for the EO and from 19.56 to 408.85 mg L-1 for the nanoemulsions. In the anti-inflammatory activity assay, an EC50 of 62.46 mgL-1 was obtained for EO and 64.96 to 4220.25 mg L-1 for NOE’s. Finally, the pharmacological activities tested showed efficient values for EC50, therefore being considered active. This activity is attributed to the chemical compounds present, thus encouraging studies with this species aiming at its potential application in a formulated bioproduct.

Chemical profile and biotechnological potential larvicidal of a nanoemulsion (o/w) of the essential oil of Salvia officinalis L

This study aims to evaluate the chemical profile and biotechnological larvicidal potential of the nanoemulsion of the essential oil of Salvia officinalis L. The leaves of the plant were collected in São Luís, MA, from January to May 2021. The essential oil was extracted by hydrodistillation at 100°C for 3h. Chemical characterization was obtained by GC-MS. The oil-in-water nanoemulsion was formulated by the low-energy phase inversion method and subjected to thermodynamic stability tests. Antioxidant activity is performed by the spectrophotometric method of scavenging hydroxyl radicals from salicylic acid. For larvicidal activity, Aedes aegypti larvae were subjected to EO solutions and nanoemulsions in concentrations (10-100 mg L-1), larval mortality was evaluated, and the LC50 was determined by the Probit method. The majority compounds of the EO were: eucalyptol with 65.14%, camphor (30.63%), and α-Terpineol (1.53%). The formulations were characterized as nanoemulsions with a droplet size &lt;200 nm. The PDI was &lt;0.200, indicating a narrow size distribution. The antioxidant activity exhibited EC50 of 136.29 mg L-1 and 51.59 mg L-1. The nanoemulsion with larvicidal potential showed an LC50 of 71.17 mg L-1. The nanoemulsion showed bioactive potential for larvicidal action, which may be related to the presence of its chemical compounds, and its use is encouraged in the fight against Aedes aegypti.

A Dynamic Mechanical Analysis on the Compatibilization Effect of Two Different Polymer Waste-Based Compatibilizers in the Fifty/Fifty Polypropylene/Polyamide 6 Blend.

This study aims to examine the 50/50 polypropylene/polyamide 6 (iPP/PA6) system molded under confined flow conditions, both in its original state and after being modified by two different interfacial agents. This study provides two main insights. Firstly, it focuses on a polymer blend close to phase inversion. Secondly, it investigates the impact of using two different types of interfacial agents (derived from polymer waste) to enhance the compatibility between iPP and PA6. Dynamic Mechanical Analysis (DMA) has been employed to achieve these objectives. It is important to note that the investigation of the 50/50 iPP/PA6 system is a crucial focus predicted in previous studies, where a series of mechanical properties were evaluated using Box-Wilson design of experiments (DOEs) over the whole compositional range on the iPP/PA6 binary system. Thus, two interfacial modifiers, namely succinic anhydride (SA)-grafted atactic polypropylene with terminal, side, and bridge SA grafts (aPP-SASA) and succinyl-fluoresceine (SF) with bridge succinic anhydride grafting atactic polypropylene (aPP-SFSA), were employed. The authors obtained and characterized these agents. The quantity of these agents used in the blend was identified as a critical coordinate in prior studies conducted by the authors. The processing method used, compression molding under confined conditions, was chosen to minimize any orientation effect on the emerging morphology. All characterization procedures were performed on samples processed by contour machining to retain the blend morphologies as they emerged from the processing stage. Results from WAXS and SAXS synchrotron tests concluded there were no changes in the crystal morphology of the iPP or the PA6 in the blends nor any co-crystallization process throughout the compositional range. These findings, and the long period fits on the PP crystalline phase for the fifty/fifty blends we are discussing, will support the present DMA study. Finally, the efficiency of these interfacial modifiers has been concluded, even in this unfavorable scenario.

Amphiphilic Nanogels as Versatile Stabilizers for Pickering Emulsions.

Pickering emulsions (PEs) are stabilized by particles at the water/oil interface and exhibit superior long-term stability compared to emulsions with molecular surfactants. Among colloidal stabilizers, nano/microgels facilitate emulsification and can introduce stimuli responsiveness. While increasing their hydrophobicity is connected to phase inversion from oil-in-water (O/W) to water-in-oil (W/O) emulsions, a predictive model to relate this phase inversion to the molecular structure of the nano/microgel network remains missing. Addressing this challenge, we developed a library of amphiphilic nanogels (ANGs) that enable adjusting their hydrophobicity while maintaining similar colloidal structures. This enabled us to systematically investigate the influence of network hydrophobicity on emulsion stabilization. We found that W/O emulsions are preferred with increasing ANG hydrophobicity, oil polarity, and oil/water ratio. For nonpolar oils, increasing emulsification temperature enabled the formation of W/O PEs that are metastable at room temperature. We connected this behavior to interfacial ANG adsorption kinetics and quantified ANG deformation and swelling in both phases via atomic force microscopy. Importantly, we developed a quantitative method to predict phase inversion by the difference in Flory-Huggins parameters between ANGs with water and oil (χwater - χoil). Overall, this study provides crucial structure-property relations to assist the design of nano/microgels for advanced PEs.

Nonreciprocal polarized transmission via bound states in the continuum.

We realize the observation of near-unity nonreciprocal polarized transmission via the bound states in the continuum (BICs) in a double-layer grating structure. By introducing out-of-plane perturbations and topological defects that break the mirror symmetry between the upper and lower layers, the far-field polarization states in momentum space are inverted vertically and horizontally, showing mirrored polarization characteristics for incident channels from different upper and lower ports. During the process of introducing mirror perturbations in the upper and lower layers, a π/2 phase inversion occurs in the Г-M direction, making chirality possible. Utilizing this bidirectionally tunable nonreciprocal spatiotemporal phase transition enables multiple modulations of polarization states and opens up more possibilities for asymmetric light manipulation in chiral optical effects.

Constructing a monolithic amino-functionalized poly(ether sulfone) loose nanofiltration membrane for efficient dye/salt fractionation

Loose nanofiltration (LNF) is a promising new technique for dye/salt separation, but LNF membranes still suffer from low permeance and inadequate selectivity. In this study, novel monolithic amino-functionalized poly(ether sulfone) (PES) LNF membranes were developed in three steps, PES powder-grafted with polyacrylonitrile (PAN) under gamma-ray irradiation and membrane preparation via non-solvent-induced phase separation, followed by an amination process. The resultant aminated PES LNF membrane with tetraethylenepentamine (APES-TP) had a thinner skin layer and unusual irregular vesicle-like pore structure in its sublayer compared with the original PES substrate. The amination process increased the hydrophilicity of the APES-TP membranes and partially neutralized the surface zeta-potential. The permeation test confirmed that the APES-TP membrane exhibited 100 % NaCl permeation together with high levels of pure water permeance (77.9 L m–2h−1 bar−1) and dye rejection (98.5 % for Congo red, 97.1 % for Nair blue, and 97.6 % for methyl blue). Even when paired with simulated industrial wastewater containing multiple direct dyes and inorganic salts (1 g L–1 dye and 5 g L–1 salts), the APES-TP membrane still rejected 99.4 % of the mixed dyes, proving its practical applicability to treating industrial dye wastewater. Furthermore, the APES-TP membrane exhibited excellent endurance to harsh conditions (such as acidic, alkaline, and oxidative) and exceptional recyclability (97.9 % permeance recovery rate). This study bridges the gap between conventional nonsolvent phase inversion and the emerging LNF membrane fabrication technology, allowing the LNF technique to be used to fractionate organic matters with salts in batch mode.

Anti-Oxidant and Anti-Bacterial Behavior of Sodium Alginate Patches Fortified with Polyurethane and Ag-MOF as Potential Future Wound Healing Material

ABSTRACT Sodium Alginate (SA) is a natural polysaccharide with a high degree of biocompatibility, biodegradability, water absorption properties and stiffness. The inherent brittleness of SA limits its applications in the field of wound healing. The blending of highly flexible polyurethane (PU) with SA could alter the nature of film. In addition, the incorporation of Ag-Metal Organic Framework (Ag-MOF) synthesized via the solvothermal method can help in the enhancement of stability and biological characteristics. The SA and its composite films were obtained through a feasible phase inversion technique. In addition, the Ag-MOF@SA/PU film demonstrates the strongest bacteriostatic impact on E. faecalis and P. aeruginosa, with percentages of approximately 96.9% and 96.41%, respectively. Furthermore, the film demonstrates a radical scavenging efficiency of 83.96%. Moreover, the Ag-MOF@SA/PU film exhibited a significant increase in the production of oxidative stress, attaining a value of 84.89%. Owing to the results, Ag-MOF@SA/PU was taken for in-vitro degradability analysis and visible surface erosion was observed over time. Thus, the Ag-MOF@SA/PU film could be considered for future wound healing therapy.

Adsorptive membrane separation for eco-friendly decontamination of chlorpyrifos via biochar-impregnated cellulose acetate mixed matrix membrane.

In this work, the phase inversion approach is used to synthesize a blended mixed matrix membrane from cellulose acetate polymer and sugarcane bagasse biochar. The experiments were carried out to estimate the extent of chlorpyrifos (CPS) pesticide removal. The results showed that the removal rate was more than 99% in making the filtered water suitable enough for domestic use. The physical and functional characteristics of the membranes, such as permeability, and contact angle were identified. The changes in the membrane characteristics were observed using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction both before and after the experimental trials. Experiments were conducted to assess not only the rejection characteristics of CPS, as a function feed concentration, but also the effect co-ions on the rejection used to analyze the composition both before and after filtration. The effects of initial CPS concentration, biochar loading, and co-ions on the membrane were investigated. The membranes showed contact angles between 70° and 97° and a permeability between 0.25 × 1010 m Pa-1 s-1 and 0.31 × 1010 m Pa-1 s-1. The effective removal of CPS from the contaminated aqueous stream was attributed to a combination of adsorptive uptake and membrane-based separation. CPS was found to get adsorbed onto the membrane matrix through an intraparticle diffusion mechanism along with an irreversible monolayer adsorption. The membrane-solute adsorptive interaction was represented by Langmuir isotherm and intraparticle diffusion models with a maximum adsorption capacity of 192.3 mg g-1. The findings indicated the efficacy of biochar-cellulose acetate mixed matrix membrane for sustainable and eco-friendly treatment of chlorpyrifoscontaminated water.

Chinese Herbs for Inducing Rat Bone Marrow Mesenchymal Stem Cells Differentiated into Neuron-Like Cells

The purpose of this study was to observe the influence of two Chinese herbs of ligustrazine and Xuefuzhuyu injection on neuron-like cells differentiation from rat bone marrow mesenchymal stem cells (BMSCs) respectively. Most primarily cultured BMSCs adhered to the wall at 3 days after cultured, which proliferated faster after passaged, and the 5th passage of cells were mostly purified into BMSCs. In the present study, the 5th passage of BMSCs were (97.51±1.22) % CD44 positive, but negative for CD45, which were identified by immunocytochemical technique. Serum-free low-sugar Dulbecco’s modified Eagle’s medium (L-DMEM) contains 1.25 g/L ligustrazine and 3.0 g/L Xuefuzhuyu injection were used to induce the 5th passage of BMSCs respectively in vitro. Neuron-like cells with prominence and bifurcation could be detected after induction under an inverted phase contrast microscope. The immunocytochemical method showed that nestin and neuron-specific enolase (NSE) were positive in neuron-like cells, but without glial fibrillary acidic protein (GFAP) expression. Both ligustrazine and Xuefuzhuyu injection have the potential for inducing neuron-like cells differentiation from rat bone marrow mesenchymal stem cells respectively. Compared with Xuefuzhuyu injection-induced cells, neuron-like cells induced with ligustrazine might be better in the level of morphological changes, as well as nestin and NSE expression.

Understanding Thermodynamics and Kinetics of PEDOT:PSS Using ATR-FTIR and Density Functional Theory.

This work demonstrates poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) and divinyl sulfone (DVS) cross-linking to form insoluble and porous PEDOT:PSS-DVS hydrogels. We propose a reaction mechanism and demonstrate the kinetics of a PEDOT:PSS modification that prevents PEDOT:PSS dispersibility. PSS and DVS undergo a second-order reaction between the DVS secondary carbocations and PSS oxygen anion to form a PSS-DVS network. The kinetics, from real-time attenuated total reflectance-Fourier transform infrared spectroscopy and density functional theory, reveal a temperature-dependent rate expression with a 1.458 1/s pre-exponential factor and a 2.429 kcal/mol activation energy. Cryogelation, phase separation, and phase inversion methods induce porosity in the PEDOT:PSS-DVS hydrogels with pore sizes ranging from 12 to 121 μm. Most importantly, the porous PEDOT:PSS-DVS hydrogels do not redisperse in solution. The results provide evidence for the reaction mechanism and kinetics of porous nondispersible PEDOT:PSS-DVS hydrogels.

Ball milling and annealing effect in structural and magnetic properties of copper ferrite by ceramic synthesis

This study aims to better understand the relationship between the microstructure and magnetic properties of copper ferrite, which is an inverse spinel that present a body-centered tetragonal structure associated with a remarkable Jahn–Teller (JT) effect. For this goal, a sample has been synthesized by the ceramic route from a stoichiometric mixture of high-purity CuO and Fe2O3 powders activated mechanically in a high-energy planetary ball mill. This sample was calcined in air furnace at 1000 ºC for 6 h. As synthetized sample with a cubic structure was divided into two parts and one of them was annealed at 650 ºC for 3 h and slowly cooled to room temperature to obtain a pure tetragonal spinel sample. Furthermore, these two samples were subjected to the same processes of severe plastic deformation by milling for up to 70 h and subsequent annealing at temperatures ranging between 300 and 600 ºC to obtain samples with a mixture of phases in different proportions. For the cubic one, there is no change in its structure due to milling, always remaining 100 % cubic, and the evolution in the saturation magnetization was related to the changes in the density of defects present. On the other hand, copper cations are always found in the octahedral sites of spinel with a tetragonal structure. The small decrease in the degree of inversion to 0.95 induced by milling in this sample is capable of breaking the JT distortion, giving rise to the appearance of a cubic phase. This work demonstrates how the structure, microstructure, defects like stacking faults and deformation twins, and degree of inversion of the different phases are related to changes in magnetic properties.