Addition Of Polyvinylpyrrolidone Research Articles

Modulating interfacial polymerization dynamics in nanostructured thin-film composite membranes: The role of polyvinylpyrrolidone and NaCl

Optimizing the performance of thin-film composite polyamide (TFC-PA) membranes is crucial for enhancing filtration efficiency across diverse applications. This study investigated the role of polyvinylpyrrolidone (PVP) in modulating the diffusion kinetics of piperazine (PIP) during the interfacial polymerization (IP) process, essential for membrane fabrication. By incorporating PVP into the aqueous phase, and combining it with selected inorganic salts such as sodium chloride (NaCl), the formation of a more controlled Turing-like nanostructure within the PA layer was achieved, significantly improving membrane permeability and structural uniformity. Employing molecular simulations alongside diverse characterization techniques, the mechanisms by which PVP and NaCl additives influence the diffusion of PIP monomers at the water-oil interface were elucidated. The optimized membranes demonstrated a substantial increase in water permeability, achieving 16.2 ± 0.9 L m−2 h−1 bar−1, and an impressive sodium sulfate (Na2SO4) rejection rate of 97.5 ± 0.6 %, outperforming untreated nanofiltration (NF) membranes. The findings provide a deeper understanding of the molecular interactions during IP and open avenues for the development of advanced filtration membranes with tailored properties.

2D Ruddlesden-Popper Perovskites with Polymer Additive as Stable and Transparent Optoelectronic Materials for Building-Integrated Applications.

We report on the use of 2D Ruddlesden-Popper (RP) perovskites as optoelectronic materials in building-integrated applications, addressing the challenge of balancing transparency, photoluminescence, and stability. With the addition of polyvinylpyrrolidone (PVP), the 2D RP films exhibit superior transparency compared to their 3D counterparts with an average visible transmittance (AVT) greater than 50% and photoluminescence stability under continuous illumination and 85 °C heat for up to 100 h as bare, unencapsulated films. Structural investigations show a stress relaxation in the 3D perovskite films after degradation from thermal aging that is not observed in the 2D RP films, which retain their phase after thermal and light aging. We also demonstrate ultrasmooth, wide-bandgap 2D Dion-Jacobson (DJ) films with PVP incorporation up to 2.95 eV, an AVT above 70%, and roughnesses of ~2 nm. These findings contribute to the development of next-generation solar materials, paving the way for their integration into built structures.

Synergistic effect of pore generation and nitrogen doping on the enhanced CO2 capture and selectivity of carbon nanofibers

The porosity and heteroatom doping of carbon materials are crucial for their adsorption capacity and selectivity toward CO2. Herein, nitrogen-doped microporous carbon nanofibers (CNFs) were prepared by carbonizing electrospun polyacrylonitrile (PAN) nanofibers, using nitrogen-rich polyvinylpyrrolidone (PVP) as porogen and nitrogen source simultaneously. The synergistic effect of pore generation and nitrogen doping improved the porosity and preserved a substantial nitrogen content in the CNFs. Compared to the nitrogen-free polyethylene glycol (PEG) porogen, the incorporation of PVP can facilitate nitrogen doping during the carbonization process. With an increasing amount of PVP addition, the specific surface area of the CNFs significantly expanded to 410 m2/g, maintaining a high nitrogen content of 10.32 wt%. The porosity and nitrogen functionalities (Pyridinic N and pyrrolic N) collaborated synergistically in determining CO2 adsorption capacity, with elevated nitrogen content resulted in improved selectivity. The CNFs exhibited remarkable IAST CO2/N2 (10:90) selectivity of 38 and cycling stability, demonstrating their potential for long-term practical applications. This work provides unique inspiration for the design of porous nanofibers with exceptional CO2 adsorption capacity and selectivity.

Constructing Porous Energetic Spherulites via Solvation-Growth Coupling for Enhanced Combustion.

The fabrication of materials with hierarchical structures has garnered great interest, owing to the potential for significantly enhancing their functions. Herein, a strategy of coupling molecular solvation and crystal growth is presented to fabricate porous spherulites of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), an important energetic material. With the addition of polyvinylpyrrolidone in the antisolvent crystallization, the metastable solvate of CL-20 is formed and grows spherulitically, and spontaneously desolvates to obtain the porous spherulite when filtration, in which the characteristic peak of the nitro group of CL-20 shifts detected by the in situ micro-confocal Raman spectroscopy. The effect of polyvinylpyrrolidone is thought to induce the solvation of CL-20, confirmed by density functional theory calculations, meanwhile acting on the (020) face of CL-20 to trigger spherulitic growth, demonstrated through infrared spectroscopy and Rietveld refinement of powder X-ray diffraction. Moreover, compared to common CL-20 crystals, porous spherulites exhibit enhanced combustion with increases of 6.24% in peak pressure, 40.21% in pressurization rate, and 9.63% in pressure duration effect, indicating the capability of hierarchical structures to boost the energy release of energetic crystals. This work demonstrates a new route via solvation-growth coupling to construct hierarchical structures for organic crystals and provides insight into the structure-property relations for material design.

Surfactant assisted tuning of electrical conductivity, electromagnetic interference shielding effectiveness, wetting properties of poly(lactic acid)-expanded graphite-magnetite nanocube hybrid bio-nanocomposites

The study aimed at demonstrating polyvinylpyrrolidone (PVP) amount is critical for tuning electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of poly(lactic acid)-expanded graphite (ExGr)-magnetite (Fe3O4) nanocube hybrid nanocomposites. An optimum loading of PVP (1 wt.%) was found to disperse the nanofillers resulting in enhanced electrical conductivity and EMI SE in the X-band dominated by the absorption mechanism. The electrical conductivity enhancement in hybrid nanocomposites was not only attributed to the network formation between fillers but also to the thickness of the coated surfactant layer. The inter-junction capacitance and real part of relative permittivity of the hybrid nanocomposites were also enhanced at 1 wt.% PVP addition in comparison to 0 wt.% and 2 wt.% surfactant loading. The water contact angle was found to depend on the surface roughness of the film, which varied with both PVP and ExGr loadings. These PLA-based hybrid nanocomposites can be used as microwave-absorbing material.

Micro and nanostructured carbon-phenolic ablators modified by PVP addition

Carbon-phenolic ablators can efficiently protect space vehicles from the extreme temperatures typical of the reentry phase in a planet’s atmosphere. Their performances are attributed to the low thermal conductivity and to the decomposition of the phenolic resin. These phenomena are strongly influenced by the materials microstructure. In the present work, standard and polyvinylpyrrolidone (PVP)-modified carbon-phenolic ablators were manufactured and characterized: the influence of PVP on the final microstructure and chemistry of the ablators was studied through SEM-EDS, X-ray Microscopy (XRM) analysis and FTIR technique; the mechanical properties were evaluated through compression tests on virgin and charred samples while ablative performance of the ablators were evaluated with an oxyacetylene flame exposure test. Weak bonds between phenolic resin chains and PVP were observed. The microstructure of the ablators, both before and after the exposure to the oxyacetylene flame, is strongly influenced by the PVP addition, furthermore the addition of 10 and 20 %wt of PVP can guarantee a reduction of about 30 % of the back temperature during the oxyacetylene flame test with respect to the standard carbon-phenolic ablator. Compression tests on the manufactured ablators enlighten also an improvement in the mechanical properties for PVP-enriched ablators, in particular considering their charred state.

Preparation of high color fastness structural colored cotton fabric via SiO2@PDA photonic crystal

Structural color is an important way to achieve the ecological coloring of textiles. SiO2 microspheres with sizes in the range of 200–337 nm were synthesized by the Stober method and then covered with highly light-absorbing melanin PDA to form SiO2@PDA photonic crystals. The SiO2@PDA photonic crystals were assembled onto the surface of white cotton fabrics by gravity deposition to achieve structural color. The addition of polyvinylpyrrolidone (PVP) enhances interfacial bonding by forming multiple hydrogen bonds between its lactam group and the phenolic hydroxyl group of PDA, resulting in a structured color cotton fabric with high color fastness. Scanning electron microscopy (SEM) was used to study the structure and morphology of SiO2@PDA microspheres. The chemical compositions of PDA and PVP were surveyed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The surface structural color of cotton fabrics was investigated by UV–Vis reflectance spectroscopy.

Influence of PVP on the properties of solvothermally synthesized famatinite nanoparticles: Structural, morphological and optical insights

Famatinite (Cu3SbS4) nanoparticles were synthesized through a solvothermal approach using various polyvinylpyrrolidone (PVP) ratios as a capping agent with a binary solvent of ethylene glycol and water in equal parts. Incremental additions of PVP, ranging from 0 to 1.5 g, exerted significant influence on the material's characteristics. Through comprehensive analysis involving X-ray diffraction, Raman spectroscopy, Scanning electron microscopy (SEM) with Energy dispersive spectrometer (EDS), and UV diffuse reflectance spectroscopy, critical insights were obtained. XRD analysis confirmed the tetragonal crystal structure and revealed reduced crystallite sizes due to the incorporation of PVP. Raman spectroscopy validated the presence of pure famatinite phase with 0.5 g and 1.0 g PVP. SEM analysis uniformly depicted a spherical morphology in all samples, emphasizing PVP's role in mitigating nanoparticle agglomeration. UV diffuse reflectance spectroscopy disclosed direct bandgaps falling within the 0.88 – 0.97 eV range. The collective findings highlighted the substantial impact of PVP in the binary solvent on the structural, morphological, and optical properties of Cu3SbS4 nanoparticles. These results underscore the potential application of these tailored nanoparticles as promising candidates for advanced photovoltaic absorber materials.

A sub-10 nm polyamide nanofiltration membrane from polyvinylpyrrolidone-mediated interfacial polymerization

In conventional interfacial polymerization (IP) for thin-film composite nanofiltration membranes, the separation layer is typically thick (∼100 nm), which limits its water permeance. In this study, we successfully synthesized an ultrathin polyamide layer (∼8.6 nm) from polyvinylpyrrolidone (PVP)-mediated IP. With the surfactant concentration over its critical micelle concentration, PVP not only formed a monolayer at the water-heptane interface, but also stayed in the aqueous solution. The CO groups of PVP formed the N–H⋯O hydrogen bond interactions with N–H bonds of piperazine (PIP) monomers in the aqueous phase to slow down the diffusion of PIP monomers. Besides, PVP with amphiphilic groups minimized the interfacial tension at the water-heptane interface to regulate IP processes. By adjusting the concentration of PVP, we obtained a sub-10 nm polyamide nanofiltration membrane. Moreover, hydrophilic PVP macromolecules improved the membrane surface hydrophilicity. Due to the ultrathin thickness and improved hydrophilicity, the optimized polyamide membrane demonstrated a threefold increase in permeance compared to that of the pristine polyamide membrane without PVP addition, and maintained 98.4% rejection for 1000 ppm Na2SO4 solution. This study provides a new insight into fabricating sub-10 nm polyamide membranes for nanofiltration processes.

Cryopreservation of European flat oyster (Ostrea edulis) larvae using a controlled-rate freezer

Larvae of the European flat oyster (Ostrea edulis) were cryopreserved using two protocols originally developed for other bivalvian species with several modifications. Culture of the European flat oyster went through several setbacks due to parasitic diseases, thus, assisted reproductive technologies such as larval cryopreservation can aid in prompt restoration of lost populations and thus facilitate farming of the species. Veliger larvae were diluted in two basic extenders (0.4 M trehalose or 0.4 M sucrose) supplemented with ethylene glycol (EG), dimethyl-sulfoxide (DMSO) or propylene glycol (PG) in concentrations of 10–20% with or without the addition of polyvinylpyrrolidone (average MW-40,000; PVP-40). Larvae were loaded into 0.25-ml or 0.5-ml straws and cryopreserved in a controlled-rate freezer using two slow cooling profiles. Assessment of larval survival 20 min or 24 h post-thaw revealed that the cooling profiles and the type of extender used did not have a significant effect on survival rates. On the other hand, the type of cryoprotectant, straw volume and the time of assessment had a significant main effect on larval survival percentages (p < 0.001 in all three cases). Survival percentages of 70–80% were observed 20 min post-thaw which decreased to 40–60% at 24 h. Generally, EG and DMSO resulted in higher post-thaw larval survival than did PG when larvae were cryopreserved in 0.25-ml straws, whereas, these differences were not detected when 0.5-ml straws were employed. Results of these experiments will allow later studies on long-term survival of cryopreserved European flat oyster larvae.

Seedless and electroless plating of silver on silica particles by using microreactor

Synthesis of silver nanoshells is still a challenge especially in the absence of surface modification of core particles and/or metal seed decoration on core surfaces. In this study, we applied a microrector to seedless and electroless plating of silver on bare silica particles, and investigated the effects of reaction temperatures and silver ion concentrations on the morphology and surface coverage of silver on the core particle surface. Our experiments demonstrated that the use of the microreactor enabled the one-step direct deposition of silver with a morphology close to complete shells and that silver ion concentrations from 0.2 to 0.5 mM at a moderate temperature of 50 °C produced high coverage and yield. Besides, the mixing sequence of NH3 and HCHO in the synthesis procedure was found to be a key factor to achieve the high silver coverage. In addition, we demonstrated that the addition of polyvinylpyrrolidone (PVP) after the silver shell growth reaction increases the stability without decreasing the reaction rate.

Refinement of Nanoporous Cu by Polyvinylpyrrolidone and Photodegradation of Methyl Orange by Cu2O Nanowires and Nanoporous Cu Photocatalysts

Refinement of nanoporous Cu (NP Cu) by the addition of Polyvinylpyrrolidone (PVP) in HF solution during dealloying of Ti40.6Zr9.4Cu40.6Ni6.3Sn3.1 amorphous ribbons and effect of the surface coverage of Cu2O nanowires obtained by immersing NP Cu in dehydrated ethanol on the photodegradation of methyl orange (MO) pollutants were investigated. The sizes of pores and ligaments of NP Cu decrease significantly with the increase of PVP concentration in the dealloying solutions, accompanied by a drastic decrease in the surface diffusivity and the dislocation defect densities. The surface coverage of Cu2O nanowires becomes higher with an increase of the PVP reagents. The Cu2O nanowires@nanoporous Cu (Cu2O@NP Cu) catalysts show excellent photocatalytic activity towards the degradation of MO under the sunlight due to the existence of large amounts of heterojunctions between Cu2O nanowires and Cu ligaments in nanoscale.

Research on Urea Oxidation Coupled with Electrolysis of Water to Produce Hydrogen Based on (NiFe)2P Catalyst

Hydrogen production at low potential was realized by urea oxidation coupled water electrolysis. Transition metal phosphides ((NiFe)2P) were prepared by regulating polyvinylpyrrolidone (PVP) addition during the materials preparation, and their electrocatalytic performance for urea oxidation coupled hydrogen production was investigated. It was found that the material prepared with the PVP addition of 300 mg shows the best catalytic activity. The potential required to reach 100 mA cm−2 in KOH+urea solution is only 1.433 V with an impedance value of 4.128 Ω, which is 103 mV lower than that in KOH solution. Hydrogen evolution in KOH solution required 414 mV to reach −100 mA cm−2 with an impedance value of 48.75 Ω, while the potential required to reach the same current density in KOH+urea solution is only 343 mA with an impedance value of 5.65 Ω. As a result, the energy barrier and electron transfer resistance of electrocatalytic reaction can be significantly reduced by urea oxidation, and it provides a strategy for large-scale application of water electrolysis.

Synthesis of Modified Polyvinyl Pyrrolidone (PVP) Silver Nanoparticles Using Soursop (Annona muricata Linn) Leaf Extract and Its Application as a Heavy Metal Colorimetric Sensor

This study aims to analyze the characteristics and performance of silver nanoparticles (AgNP) synthesized using soursop leaf extract bioreductor modified with the addition of polyvinyl pyrrolidone (PVP) stabilizer as a colorimetric sensor for heavy metal ions. The synthesis of silver nanoparticles was carried out by reducing AgNO3 using soursop leaf extract (Annona muricata Linn) bioreductor modified with the addition of PVP as stabilizer. The results showed that the optimum synthesis volume ratio of AgNP synthesis was 0.7 mL of soursop leaf extract: 10 mL AgNO3 with the addition of 3% PVP stabilizer. The formation of AgNP was characterized by a change in the color of the solution from yellow to brownish with a surface plasmon resonance peak at a maximum wavelength of 438 nm. Fourier-transform infrared spectroscopy studies showed hydroxyl groups (-OH) and carbonyl groups (C=O) play a role in the reduction process of silver ions. Particle size analysis results demonstrated an average particle size of 71.5 nm with a polydispersity index value of 0.364. The results of the colorimetric analysis showed that the synthesized AgNPs proved to be highly selective towards Cu metal ions.

An Efficient Agrobacterium-Mediated Genetic Transformation System for Gene Editing in Strawberry (Fragaria × ananassa).

The octoploid-cultivated strawberry variety Benihope (Fragaria × ananassa Duch cv. Benihope) is an important commercial plant. It is highly susceptible to different diseases, which ultimately leads to a reduction in yield. Gene-editing methods, such as CRISPR/Cas9, demonstrate potential for improving disease resistance in the strawberry cv. Benihope. Establishing a plant regeneration system suitable for CRISPR/Cas9 gene editing is crucial for obtaining transgenic plants on a large scale. This research established a callus induction and plant regeneration system for Agrobacterium-mediated CRISPR/Cas9 gene editing in strawberry cv. Benihope by evaluating multiple types of explants and various plant growth regulators throughout the entire tissue culture process. The results showed that the efficiency of callus induction is strongly influenced by the type of explant and is highly sensitive to the combination of plant growth regulators. Among the different plant growth regulators employed, thidiazuron (TDZ), in combination with 2,4-dichlorophenoxyacetic acid (2,4-D), effectively induced callus formation and plant regeneration from explants derived from nutrient tissues such as runner tips and crowns. In addition, the regeneration experiment demonstrated that the addition of polyvinylpyrrolidone (PVPP) to the shoot regeneration medium could inhibit tissue browning. The gene-edited plants in which some or all of the Fvb7-1, Fvb7-2, Fvb7-3, and Fvb7-4 genes in the MLO (Mildew resistance Locus O) gene family were knocked out by CRISPR/Cas9 system were obtained by applying the plant regeneration system developed in this study.

Effect of Incorporation of Poly Vinyl Pyrrolidone on Transverse Strength, Impact Strength and Surface Roughness of Autopolymerizing Acrylic Resin

Autopolymerizing acrylic resin is one of the most frequently used materials in dentistry, but it has relatively poor mechanical properties This study investigated the effect of the addition of poly vinyl pyrrolidone on transverse strength, impact strength and surface roughness of autopolymerzing acrylic resin. A total of 60 specimens were prepared, 30 specimens of each conventional and modified autoplymerizing acrylic.20 specimens of each groups were fabricated with dimensions of (64×10×2.5) mm to conduct the transverse strength and surface roughness tests, while the remaining 10 specimens of each group were fabricated with dimensions of (80×10×4) mm to perform the impact strength test. The results of this study showed that the modified autopolytmerized acrylic had significantly higher transverse strength, and significantly lower surface roughness values while there was no significant differences in impact strength value. It can be concluded that addition of Polyvinylpyrrolidone can improve transverse strength and surface roughness of autopolymerizing acrylic resin.

The reinforcement strategy of electrophoretic deposition coating assisted by PVP for grain boundary diffusion of Nd-Fe-B magnet

In this study, we aimed to enhance the quality of electrophoretic deposition (EPD) coatings for Nd-Fe-B grain boundary diffusion (GBD) by addressing issues related to the adhesion and densification of coating. We introduced a novel approach by incorporating polyvinyl pyrrolidone (PVP) into an alcohol suspension containing TbH3 nano-powders. The addition of PVP resulted in the formation of a dense coating with superior adhesion and a smooth surface. To evaluate the effectiveness of the EPD coating with PVP, we compared the EPD rate of the TbH3 nano-powders alcohol suspension with and without PVP. The EPD rate of the suspension with PVP exhibited a significant 30-fold increase compared to the suspension without PVP, indicating a substantial improvement in the electrophoretic efficiency. Based on our experimental findings, we recommend depositing the EPD coating at a voltage of 120 V and adjusting the deposition time accordingly to achieve a desired coating weight percentage of 1.0 wt% with a thickness of approximately 30 μm. Following the GBD process, the coercivity of the magnet with PVP increased from 1131 kA/m to 1896 kA/m, which improved the high-temperature stability of the magnet. Overall, our research offers a promising approach to overcome the limitations associated with EPD coatings for GBD applications, providing a potential solution for enhancing the performance and industrial viability of these coatings.

Grain growth of ZnO nanocrystals synthesized in polyol medium with polyvinylpyrrolidone additives

In this work, we have investigated the influence of annealing temperature on the grain growth of zinc oxide nanocrystals synthesized in ethylene glycol and isothermally calcined at Ta: 300 °C, 500 °C, 700 °C for 60 min at the ambient atmosphere. The effect of polyvinylpyrrolidone (PVP) addition and annealing temperature on ZnO nanocrystal's phase composition, structural (scattering domain size of nanocrystallites L, unit lattice parameters a, c, and unit volume Vunit, theoretical density ρx) parameters, morphological (size, shape, specific surface area SSA) features, chemical composition, and grain growth kinetics were determined. It was found that Ta caused the increase in L of single-phase ZnO nanocrystals from 18 nm to 40 nm (with adding PVP) and to 45 nm (without adding PVP). Despite the surfactant composition, submicron grain sizes (D = 120–150 nm) were observed at Ta = 700 °C. The activation energy of grain growth was Q = 121.4 kJ/mol (without adding PVP) and Q = 126.4 kJ/mol (with adding PVP), while grain growth exponent was n = 1.9 (without adding PVP) and n = 2.0 (with adding PVP). ZnO nanocrystals annealed at 700 °C are forthcoming in the design of the active layers of solar cells, and at (300–500) °C are suitable for thermoelectric converters.

Dimensional stability of acrylic denture base material after poly vinyl pyrrolidone addition

Problem Denture base dimensional changes were found with commercial theremocured acrylic resins. The dimensional stability of acrylic resin denture base is the main necessity effects the retention and stability of the denture. This study was conducted to measure the dimensional accuracy of experimental prepared material in comparison with control material before and after thermo cycling cured by water bath and microwave. In this stady the total (40) specimens of heat cure acrylic resin lower denture base were cured by water bath and microwave after addition poly vinyl pyrrolidone (PVP). (Experimental). Preparation of modified heat cured denture base acrylic resin was carried out by preparing of (PMMA) (80%) and poly vinyl pyrrolidone (PVP) (20%) and the liquid part composed of methyl methacrylate (MMA) monomer. Evaluation was made by measuring dimensional stability and accuracy. Distances were measured between (3) points marked on denture bases "AB, AC and BC" before and after thermo cycling for both control and experimental groups. The result of this study showed that there was no significant differences (p&gt;0.05) between control and experimental groups at three point "AB, AC and BC" before and after thremocycling. Dimensional stability and accuracy was not influenced by addition of PVP to acrylic denture base resin before and after thermo cycling in both heat and microwave treatment.

Microwave‐assisted reflux synthesis of Tungsten‐doped BiVO4 for improved photocatalytic activity

AbstractGiven its favorable physical and chemical properties, Bismuth vanadate (BiVO4) is a commonly studied metal oxide semiconductor for photocatalytic applications. However, BiVO4 shows a high recombination rate of photogenerated charges and limited charge transport capacity, which can be addressed by doping it with tungsten. To develop a highly efficient tungsten‐doped BiVO4‐based (W‐BiVO4) photocatalyst, it is necessary to control the dopant content, crystal structure, and morphology. These properties are, in turn, governed by the synthesis conditions. This work describes a pioneering method of microwave‐assisted reflux synthesis of W‐BiVO4, using ethanol as solvent and polyvinyl pyrrolidone (PVP) as a capping agent. Thus, it is possible to perform the synthesis procedure in only 30 min at 78°C, obtaining extremely regular monoclinic W‐BiVO4 nanosquares. Furthermore, the experiments showed that the most efficient photocatalyst contains 3% tungsten as the dopant. Moreover, the direct oxidation of rhodamine B by the photogenerated holes plays a crucial role in the degradation mechanism. Finally, we observed that although the addition of PVP promotes control of the morphology, it results in a poorly efficient material. This low efficiency may be related to the formation of a polymeric coating on the surface of the catalyst or to a high amount of oxygen defects. Finally, we show that the unique interaction of microwaves with the species present in the reaction media influences nanoparticle growth.