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Global water scarcity is a threat that can be alleviated through membrane filtration technologies. However, the widespread adoption of membranes faces significant challenges, primarily due to membrane biofouling. This is the reason why membrane modifications have been under increasing investigation to address the fouling issues. Antibacterial membranes, designed to combat biofouling by eliminating microorganisms, offer a promising solution. Within this study, flat sheet ultrafiltration (UF) membranes with integrated photocatalytic zinc oxide (ZnO) nanoparticles were developed, characterized, and assessed through filtration and fouling tests. The antibacterial properties of the membranes were conducted in static tests using Gram-negative bacteria—Escherichia coli—and natural tap water biofilm. The results demonstrated a notable enhancement in membrane surface wettability and fouling resistance. Furthermore, the incorporation of ZnO resulted in substantial photocatalytic antibacterial activity, inactivating over 99.9% of cultivable E. coli. The antibacterial activity persisted even in the absence of light. At the same time, the persistence of natural tap water organisms in biofilms of modified membranes necessitates further in-depth research on complex biofilm interactions with such membranes.

Flexible antibacterial materials have gained utmost importance in protection from the distribution of bacteria and viruses due to the exceptional variety of applications. Herein, we demonstrate a readily scalable and rapid single-step approach for producing durable ZnO nanoparticle antibacterial coating on flexible polymer substrates at room temperature. Substrates used are polystyrene, poly(ethylene-co-vinyl acetate) copolymer, poly(methyl methacrylate), polypropylene, high density polyethylene and a commercial acrylate type adhesive tape. The deposition was achieved by a spin-coating process using a slurry of ZnO nanoparticles in toluene. A stable modification layer was obtained when toluene was a solvent for the polymer substrates, namely polystyrene and poly(ethylene-co-vinyl acetate). These coatings show high antibacterial efficiency causing >5 log decrease in the viable counts of Gram-negative bacteria Escherichia. coli and Gram-positive bacteria Staphylococcus aureus in 120 min. Even after tapping these coated surfaces 500 times, the antibacterial properties remained unchanged, showing that the coating obtained by the presented method is very robust. In contrast to the above findings, the coatings are unstable when toluene is not a solvent for the substrate.

Rapid population growth and the associated rise in industrialization and food production have resulted in a tremendously increased demand for clean water.

A tetra-ester (TE) functionalized organic compound was synthesized for the restoration the mechanical properties of the PVC/Mg(OH) 2 nanocomposites. The organically modified Mg(OH) 2 nanoparticles (OMN) were prepared by surface modification of Mg(OH) 2 nanoparticles (MDH) using a methylated tetra-phenol (TP) organic compound to achieve the homogeneous MDH distribution in the nanocomposite matrix. The results of FT-IR, XRD, and FE-SEM revealed the successful surface treating of MDH. The PVC nanocomposites were prepared by solvent blending and casting method. From the TGA analyses, the 10% mass loss temperature and the char yield of PVC containing 3% by mass of OMN and 3% by mass of TE, in N 2 atmosphere, increased by 13 °C and 7%, respectively, compared to unfilled PVC. From the microscale combustion calorimeter, a decreasing heat release rate from 125.2 to 92.8 W g –1 was observed for PVC film filled with 6% by mass of each additive, compared to unfilled PVC. The tensile test results revealed that TE and OMN have been effective for the improvement of the PVC tensile strength. For example, incorporating only 6% by mass of each filler led to an improvement in tensile strength from 58.99 to 80.58 MPa, compared to unfilled PVC.

A tetra-ester (TE) functionalized organic compound was synthesized for the restoration the mechanical properties of the PVC/Mg(OH).sub.2 nanocomposites. The organically modified Mg(OH).sub.2 nanoparticles (OMN) were prepared by surface modification of Mg(OH).sub.2 nanoparticles (MDH) using a methylated tetra-phenol (TP) organic compound to achieve the homogeneous MDH distribution in the nanocomposite matrix. The results of FT-IR, XRD, and FE-SEM revealed the successful surface treating of MDH. The PVC nanocomposites were prepared by solvent blending and casting method. From the TGA analyses, the 10% mass loss temperature and the char yield of PVC containing 3% by mass of OMN and 3% by mass of TE, in N.sub.2 atmosphere, increased by 13 °C and 7%, respectively, compared to unfilled PVC. From the microscale combustion calorimeter, a decreasing heat release rate from 125.2 to 92.8 W g.sup.-1 was observed for PVC film filled with 6% by mass of each additive, compared to unfilled PVC. The tensile test results revealed that TE and OMN have been effective for the improvement of the PVC tensile strength. For example, incorporating only 6% by mass of each filler led to an improvement in tensile strength from 58.99 to 80.58 MPa, compared to unfilled PVC.

State-of-the-art Li batteries suffer from serious safety hazards caused by the reactivity of lithium and the flammable nature of liquid electrolytes. This work develops highly efficient solid-state electrolytes consisting of imidazolium-containing polyionic liquids (PILs) and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI). By employing PIL/LiTFSI electrolyte membranes blended with poly(propylene carbonate) (PPC), we addressed the problem of combining ionic conductivity and mechanical properties in one material. It was found that PPC acts as a mechanically reinforcing component that does not reduce but even enhances the ionic conductivity. While pure PILs are liquids, the tricomponent PPC/PIL/LiTFSI blends are rubber-like materials with a Young’s modulus in the range of 100 MPa. The high mechanical strength of the material enables fabrication of mechanically robust free-standing membranes. The tricomponent PPC/PIL/LiTFSI membranes have an ionic conductivity of 10−6 S·cm−1 at room temperature, exhibiting conductivity that is two orders of magnitude greater than bicomponent PPC/LiTFSI membranes. At 60 °C, the conductivity of PPC/PIL/LiTFSI membranes increases to 10−5 S·cm−1 and further increases to 10−3 S·cm−1 in the presence of plasticizers. Cyclic voltammetry measurements reveal good electrochemical stability of the tricomponent PIL/PPC/LiTFSI membrane that potentially ranges from 0 to 4.5 V vs. Li/Li+. The mechanically reinforced membranes developed in this work are promising electrolytes for potential applications in solid-state batteries.

State-of-the-art Li batteries suffer from serious safety hazards caused by the reactivity of lithium and the flammable nature of liquid electrolytes. This work develops highly efficient solid-state electrolytes consisting of imidazolium-containing polyionic liquids (PILs) and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI). By employing PIL/LiTFSI electrolyte membranes blended with poly(propylene carbonate) (PPC), we addressed the problem of combining ionic conductivity and mechanical properties in one material. It was found that PPC acts as a mechanically reinforcing component that does not reduce but even enhances the ionic conductivity. While pure PILs are liquids, the tricomponent PPC/PIL/LiTFSI blends are rubber-like materials with a Young’s modulus in the range of 100 MPa. The high mechanical strength of the material enables fabrication of mechanically robust free-standing membranes. The tricomponent PPC/PIL/LiTFSI membranes have an ionic conductivity of 10[sup.−6] S·cm[sup.−1] at room temperature, exhibiting conductivity that is two orders of magnitude greater than bicomponent PPC/LiTFSI membranes. At 60 °C, the conductivity of PPC/PIL/LiTFSI membranes increases to 10[sup.−5] S·cm[sup.−1] and further increases to 10[sup.−3] S·cm[sup.−1] in the presence of plasticizers. Cyclic voltammetry measurements reveal good electrochemical stability of the tricomponent PIL/PPC/LiTFSI membrane that potentially ranges from 0 to 4.5 V vs. Li/Li+. The mechanically reinforced membranes developed in this work are promising electrolytes for potential applications in solid-state batteries.

In this work cross-linked hybrid organic-inorganic membranes consisting of polymeric matrix functionalized with sulfonic groups and uniformly distributed silica domains have been successfully synthesized through in situ polymerization strategy via photo-initiated copolymerization of acrylic monomers (acrylonitrile AN, acrylamide AAm, 3-sulfopropyl acrylate potassium salt SPAK) and simultaneous formation of silica counterpart using TEOS-based sol-gel system. N,N′- methylenebis(acrylamide) (MBA) was used as a cross-linker. The ratio between monomers was maintained stable, whereas the amount of added sol-gel system was varied. The influence of inorganic component content on properties of hybrid polymer-inorganic membranes was investigated. Chemical composition, thermal properties, structure and morphology of the obtained hybrid membranes were investigated by ATR-FTIR, TGA, DSC, SEM and EFTEM. Proton conductivity of the synthesized membranes was high (7.6 to 13.5 mS/cm) and increases with an increase of silica content. The prepared membranes were thermally stable up to 90 °C, and exhibited proton conductivity and swelling coefficients sufficient for possible use as proton-conducting membranes.

This chapter reviews the current state of the art in membranes for direct methanol fuel cells (DMFCs), with a particular focus on research developments. The focus is exclusively on membranes; however, given the tight integration that is necessary between membranes and the adjacent fuel/oxidant distribution layers, catalysts, and support materials, there is some mention of these materials as they must necessarily be compatible with the selected membrane. To illustrate the basic principles of DMFC operations, the chapter presents a typical, liquid‐feed cell with a cation exchange membrane. The most well‐known and well‐studied membrane materials for DMFCs are perfluorosulfonic acid membranes, such as Nafion. These macromolecules combine two different functionalities in a single macromolecule: first, the hydrophobic nature, which impacts the high chemical and thermal stability, and second, the hydrophilic sulfonic acid regions, which are responsible for the water update and ion exchange capability.