Argon Plasma Jet-Treated Poly (Vinyl Alcohol)/Chitosan and PEG 400 Plus Mangifera indica Leaf Extract for Electrospun Nanofiber Membranes: In Vitro Study

The wound-healing process can be disrupted at any stage due to various internal and external factors. The inflammatory stage of the process plays a vital role in determining the outcome of the wound. Prolonged inflammation due to bacterial infection can lead to tissue damage, slow healing, and complications. Wound dressings made using materials such as poly (vinyl alcohol) (PVA), chitosan (CS), and poly (ethylene glycol) (PEG) with Mangifera extract (ME) added can help reduce infection and inflammation, creating a conducive environment for faster healing. However, creating the electrospun membrane is challenging due to balancing various forces such as rheological behavior, conductivity, and surface tension. To improve the electrospinnability of the polymer solution, an atmospheric pressure plasma jet can induce chemistry in the solution and increase the polarity of the solvent. Thus, this research aims to investigate the effect of plasma treatment on PVA, CS, and PEG polymer solutions and fabricate ME wound dressing via electrospinning. The results indicated that increasing plasma treatment time increased the viscosity of the polymer solution, from 269 mPa∙to 331 mPa∙s after 60 min, and led to an increase in conductivity from 298 mS/cm to 330 mS/cm and an increase in nanofiber diameter from 90 ± 40 nm to 109 ± 49 nm. Incorporating 1% mangiferin extract into an electrospun nanofiber membrane has been found to increase the inhibition rates of Escherichia coli and Staphylococcus aureus by 29.2% and 61.2%, respectively. Additionally, the fiber diameter decreases when compared with the electrospun nanofiber membrane without ME. Our findings demonstrate that electrospun nanofiber membrane with ME has anti-infective properties and can promote faster wound healing.

Novel Polyelectrolyte Complex Membranes Containing Carboxymethyl Cellulose-Gelatin for Pervaporation Dehydration of Azeotropic Bioethanol for Biofuel

Polyelectrolyte complex membranes (PECMs) were prepared by combining sodium carboxymethyl cellulose (NaCMC) and gelatin (Ge) with variations in the Ge content in the NaCMC matrix. Characterization methods, such as infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), contact angle analysis (CA), and universal testing machines (UTM) were used to investigate the physicochemical studies of the prepared membranes. The pervaporation characteristics of membranes with Ge content were investigated using an azeotropic mixture of water and bioethanol. The obtained data revealed that the membrane with 15 mass% of Ge (M-3) showed a maximum flux of 7.8403 × 10^-2 kg/m²·h with separation selectivity of 2917 at 30 °C. In particular, the total and water flux of PECMs are shown as very close to each other indicating that the fabricated membranes could be employed to successfully break the azeotropic point of water-bioethanol mixtures. Using temperature-dependent permeation and diffusion data, the Arrhenius activation parameters were calculated, and the obtained values of water permeation (E_pw) were considerably smaller than bioethanol permeation (E_pE). Developed membranes showed the positive heat of sorption (ΔH_s), suggesting that Henry's sorption mode is predominant.

Modification of Thin Film Composite PVA/PAN Membranes for Pervaporation Using Aluminosilicate Nanoparticles

The effect of the modification of the polyvinyl alcohol (PVA) selective layer of thin film composite (TFC) membranes by aluminosilicate (Al₂O₃·SiO₂) nanoparticles on the structure and pervaporation performance was studied. For the first time, PVA-Al₂O₃·SiO₂/polyacrylonitrile (PAN) thin film nanocomposite (TFN) membranes for pervaporation separation of ethanol/water mixture were developed via the formation of the selective layer in dynamic mode. Selective layers of PVA/PAN and PVA-Al₂O₃·SiO₂/PAN membranes were formed via filtration of PVA aqueous solutions or PVA-Al₂O₃·SiO₂ aqueous dispersions through the ultrafiltration PAN membrane for 10 min at 0.3 MPa in dead-end mode. Average particle size and zeta potential of aluminosilicate nanoparticles in PVA aqueous solution were analyzed using the dynamic light scattering technique. Structure and surface properties of membranes were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle measurements. Membrane performance was investigated in pervaporation dehydration of ethanol/water mixtures in the broad concentration range. It was found that flux of TFN membranes decreased with addition of Al₂O₃·SiO₂ nanoparticles into the selective layer due to the increase in selective layer thickness. However, ethanol/water separation factor of TFN membranes was found to be significantly higher compared to the reference TFC membrane in the whole range of studied ethanol/water feed mixtures with different concentrations, which is attributed to the increase in membrane hydrophilicity. It was found that developed PVA-Al₂O₃·SiO₂/PAN TFN membranes were more stable in the dehydration of ethanol in the whole range of investigated concentrations as well as at different temperatures of the feed mixtures (25 °C, 35 °C, 50 °C) compared to the reference membrane which is due to the additional cross-linking of the selective layer by formation hydrogen and donor-acceptor bonds between aluminosilicate nanoparticles and PVA macromolecules.

Silicalite-1/PDMS Hybrid Membranes on Porous PVDF Supports: Preparation, Structure and Pervaporation Separation of Dichlorobenzene Isomers

Separation of dichlorobenzene (DCB) isomers with high purity by time− and energy−saving methods from their mixtures is still a great challenge in the fine chemical industry. Herein, silicalite-1 zeolites/polydimethylsiloxane (PDMS) hybrid membranes (silicalite-1/PDMS) have been successfully fabricated on the porous polyvinylidene fluoride (PVDF) supports to first investigate the pervaporation separation properties of DCB isomers. The morphology and structure of the silicalite-1 zeolites and the silicalite-1/PDMS/PVDF hybrid membranes were characterized by XRD, FTIR, SEM and BET. The results showed that the active silicalite-1/PDMS layers were dense and continuous without any longitudinal cracks and other defects with the silicalite-1 zeolites content no more than 10%. When the silicalite-1 zeolites content exceeded 10%, the surfaces of the active silicalite-1/PDMS layers became rougher, and silicalite-1 zeolites aggregated to form pile pores. The pervaporation experiments both in single-isomer and binary−isomer systems for the separation of DCB isomers was further carried out at 60 °C. The results showed that the silicalite-1/PDMS/PVDF hybrid membranes with 10% silicalite-1 zeolites content had better DCB selective separation performance than the silicalite-1/α−Al2O3 membranes prepared by template method. The permeate fluxes of the DCB isomers increased in the order of m−DCB < o−DCB < p−DCB both in single-isomer and binary-isomers solutions for the silicalite-1/PDMS/PVDF hybrid membranes. The separation factor of the silicalite-1/PDMS/PVDF hybrid membranes for p/o−DCB was 2.9 and for p/m−DCB was 4.6 in binary system. The permeate fluxes of the silicalite-1/PDMS/PVDF hybrid membranes for p−DCB in p/o−DCB and p/m−DCB binary−isomers solutions were 126.2 g∙m−2∙h−1 and 104.3 g∙m−2∙h−1, respectively. The thickness−normalized pervaporation separation index in p/o−DCB binary−isomers solutions was 4.20 μm∙kg∙m−2∙h−1 and in p/m−DCB binary−isomers solutions was 6.57 μm∙kg∙m−2∙h−1. The results demonstrated that the silicalite-1/PDMS/PVDF hybrid membranes had great potential for pervaporation separation of DCB from their mixtures.

Stretchable unidirectional liquid-transporting membrane with antibacterial and biocompatible features based on chitosan derivative and composite nanofibers

Unidirectional liquid transport is critical in achieving high-performance moisture-management fabrics for medical care. However, realizing unidirectional liquid transport while simultaneously satisfying other requirements, such as antibacterial function, adhesiveness, low cytotoxicity, and adequate mechanical strength remains a challenge. In this study, Janus nanofibrous membranes exhibiting both unidirectional liquid transport and antibacterial activity were fabricated via electrospinning and a mild crosslinking procedure. This membrane provides continuous and spontaneous unidirectional water transport with a high one-way transport value (R) of 1483%. The membrane achieved antibacterial rates of 99.2% and 98.7% against E. coli and S. aureus, respectively, without leaching antibacterial agents. In addition, it has high elasticity and self-adhesive properties, which facilitates its use in a range of applications. The design of this versatile Janus nanofibrous membrane provides a new strategy for developing novel moisture-wicking systems, particularly in the field of medical dressings.

Application of polysaccharide-based metal organic framework membranes in separation science

Polysaccharide/MOF composite membranes have captured the interests of many researchers during decontamination of polluted environments. Their popularity can be attributed to the relatively high chemical and thermal stabilities of these composite membranes. Chitosan is among the polysaccharides extensively used during the synthesis of hybrid membranes with MOFs. The applications of chitosan/MOF composite membranes in separation science are explored in detail in this paper. Researchers have also synthesised mixed matrix membranes of MOFs with cellulose and cyclodextrin that have proved to be effective during separation of a variety of materials. The uses of cellulose/MOF and cyclodextrin/MOF membranes for the removal of environmental pollutants are discussed in this review. In addition, the challenges associated with the use of these mixed matrix membranes are explored in this current paper.