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Hydrophobic fibrous slippery liquid-infused porous surfaces (SLIPS) were fabricated by electrospinning polydimethylsiloxane (PDMS) and polystyrene (PS) as a carrier polymer on plasma-treated polyethylene (PE) and polyurethane (PU) substrates. Subsequent infusion of blackseed oil (BSO) into the porous structures was applied for the preparation of the SLIPS. SLIPS with infused lubricants can act as a repellency layer and play an important role in the prevention of biofilm formation. The effect of polymer solutions used in the electrospinning process was investigated to obtain well-defined hydrophobic fibrous structures. The surface properties were analyzed through various optical, macroscopic and spectroscopic techniques. A comprehensive investigation of the surface chemistry, surface morphology/topography, and mechanical properties was carried out on selected samples at optimized conditions. The electrospun fibers prepared using a mixture of PDMS/PS in the ratio of 1:1:10 (g/g/mL) using tetrahydrofuran (THF) solvent showed the best results in terms of fiber uniformity. The subsequent infusion of BSO into the fabricated PDMS/PS fiber mats exhibited slippery behavior regarding water droplets. Moreover, prepared SLIPS exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli bacterium strains. [ABSTRACT FROM AUTHOR]

Novel 2D Ti3C2Tx (MXene)-reinforced polyvinyl alcohol (PVA) nanofibers have been successfully fabricated by an electrospinning technique. The high aspect ratio, hydrophilic surfaces, and metallic conductivity of delaminated MXene nanosheet render it promising nanofiller for high performance nanocomposites. Cellulose nanocrystals (CNC) were used to improve the mechanical properties of the nanofibers. The obtained electrospun nanofibers had diameter from 174 to 194 nm depending on ratio between PVA, CNC and MXene. Dynamic mechanical analysis demonstrated an increase in the elastic modulus from 392 MPa for neat PVA fibers to 855 MPa for fibers containing CNC and MXene at 25°C. Moreover, PVA nanofibers containing 0.14 wt. % Ti3C2Tx exhibited dc conductivity of 0.8 mS/cm conductivity which is superior compared to similar composites prepared using methods other than electrospinning. Improved mechanical and electrical characteristics of the Ti3C2Tx /CNC/PVA composites make them viable materials for high performance energy applications. [ABSTRACT FROM AUTHOR]

Simple and robust methods for modifying hydrophobic polymer surfaces with zwitterionic polymers using UV irradiation were developed. Two random zwitterionic copolymers consisting of either carboxybetaine or sulfobetaine methacrylamide monomers and monomers bearing a photolabile azidophenyl group were directly photoimmobilized on polymeric surfaces (polyester, polyethylene and polystyrene) via covalent interactions in a spatially controlled manner. These copolymers were also electrospun to form self-standing mats. The modified surfaces were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, infrared spectroscopy and contact angle measurements. The electrospinning method involved the use of a trifluoroethanol solution with a copolymer concentration in the range from 2 to 10 wt.%. BHK 21 cell adhesion to both modified surfaces and mats was dramatically reduced compared to unmodified surfaces. [ABSTRACT FROM AUTHOR]

Many polymer materials have found a wide variety of applications in biomedical industries due to their excellent mechanical properties. However, the infections associated with the biofilm formation represent serious problems resulting from the initial bacterial attachment on the polymeric surface. The development of novel slippery liquid-infused porous surfaces (SLIPSs) represents promising method for the biofilm formation prevention. These surfaces are characterized by specific microstructural roughness able to hold lubricants inside. The lubricants create a slippery layer for the repellence of various liquids, such as water and blood. In this study, effective antimicrobial modifications of polyethylene (PE) and polyurethane (PU), as commonly used medical polymers, were investigated. For this purpose, low-temperature plasma treatment was used initially for activation of the polymeric surface, thereby enhancing surface and adhesion properties. Subsequently, preparation of porous microstructures was achieved by electrospinning technique using polydimethylsiloxane (PDMS) in combination with polyamide (PA). Finally, natural black seed oil (BSO) infiltrated the produced fiber mats acting as a lubricating layer. The optimized fiber mats' production was achieved using PDMS/PA mixture at ratio 1:1:20 (g/g/mL) using isopropyl alcohol as solvent. The surface properties of produced slippery surfaces were analyzed by various microscopic and optics techniques to obtain information about wettability, sliding behavior and surface morphology/topography. The modified PE and PU substrates demonstrated slippery behavior of an impinged water droplet at a small tilting angle. Moreover, the antimicrobial effects of the produced SLIPs using black seed oil were proven against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). [ABSTRACT FROM AUTHOR]

An optimal medical scaffold should be biocompatible and biodegradable and should have adequate mechanical properties and scaffold architecture porosity, a precise three-dimensional shape, and a reasonable manufacturing method. Polylactic acid (PLA) is a natural biodegradable thermoplastic aliphatic polyester that can be fabricated into nanofiber structures through many techniques, and electrospinning is one of the most widely used methods. Medical fiber mat scaffolds have been associated with inflammation and infection and, in some cases, have resulted in tissue degradation. Therefore, surface modification with antimicrobial agents represents a suitable solution if the mechanical properties of the fiber mats are not affected. In this study, the surfaces of electrospun PLA fiber mats were modified with naturally occurring l -ascorbic acid (ASA) or fumaric acid (FA) via a plasma treatment method. It was found that 30 s of radio-frequency (RF) plasma treatment was effective enough for the wettability enhancement and hydroperoxide formation needed for subsequent grafting reactions with antimicrobial agents upon their decomposition. This modification led to changes in the surface properties of the PLA fiber mats, which were analyzed by various spectroscopic and microscopic techniques. FTIR-ATR confirmed the chemical composition changes after the modification process and the surface morphology/topography changes were proven by SEM and AFM. Moreover, nanomechanical changes of prepared PLA fiber mats were investigated by AFM using amplitude modulation-frequency modulation (AM-FM) technique. A significant enhancement in antimicrobial activity of such modified PLA fiber mats against gram-positive Staphylococcus aureus and gram-negative Escherichia coli are demonstrated herein. • The PLA fiber mats scaffolds were fabricated by electrospinning technique. • Plasma treatment created reactive centers on the PLA surface. • Ascorbic acid and fumaric acid modified the PLA surface using plasma treatment. • Modified surface of PLA led to surface properties changes. • Antimicrobial effect was proven against S. aureus and E. coli bacteria. [ABSTRACT FROM AUTHOR]

In this article, we report the preparation and properties of electro‐conductive mats based on the commercial copolyamide (Vestamelt X1010) and multiwall carbon nanotubes functionalized by amino groups. Vestamelt X1010 is easily soluble in n‐propanol at room temperature up to a concentration of 18 wt%. This is a significant advantage of this system because n‐propanol is considered to be a safe and relatively environmentally friendly solvent compared with the organic solvents and acids frequently used for electrospinning of common synthetic polymers. The co‐polyamide nanofibers were modified by multiwall carbon nanotubes grafted by amino groups to enhance their electrical conductivity at low filler content. The percolation threshold was found to be 0.33 vol%. Some applications of these mats were demonstrated such as the capability for sensing a selected vapor (acetone) and for oil/water separation. It was shown that neat Vestamelt X1010 mats remove around 85 wt% of oil (100 ppm of vegetable oil dispersed in water), whereas the addition of 1 wt% of CNTs enhances this ability up to 95 wt%. POLYM. COMPOS., 40:E1451–E1460, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this paper, we present the preparation and properties of a unique material system manufactured by electrospinning of co-polyamide 6,12 (coPA) from an n-propanol solution. A significant advantage of this system is that n-propanol is considered a safe organic solvent. According to the literature, no polymers have been electrospun from this solvent until now. The co-polyamide nanofibers were modified using cellulose nanocrystals, which were prepared by a simple one-step method from date palm leaves. This was done to enhance their mechanical properties and increase their hydrophilicity. The addition of 1 wt% of cellulose nanocrystals improved the Young's modulus by 224% and the tensile strength of the composites by 110%. The electrospun coPA fibers showed a significantly higher hydrophobicity than spin-coated foils. The contact angle of water measured on an electrospun mat was 134°, whereas the contact angle measured on a coPA foil was 84°. Selected freestanding coPA electrospun mats were tested for their potential as membranes for vegetable and diesel oil extraction from oil/water mixtures. High sorption efficiency of up to 98% was demonstrated. [ABSTRACT FROM AUTHOR]