Water Contact Angle Analysis Research Articles

Synthesis of Fluorine‐Containing, UV‐Responsive PLA‐Based Materials by Means of Functionalized DOX Monomer

Abstract1,3‐Dioxolan‐4‐ones (DOX) chemistry is exploited for the synthesis of UV‐curable, polylactic acid (PLA)‐based copolymers. DOX monomer functionalized with 4‐fluoro‐4′‐hydroxybenzophenone is synthesized and employed as comonomer with l‐lactide. Copolymerization reactions are performed with different DOX loadings through a solvent‐free, metal‐catalyzed protocol. Products are characterized through NMR analysis in order to demonstrate the random insertion of the modified monomer within the polymeric chain. Copolymers are subjected to UV irradiation and compared to a control PLA synthesized and processed in the same conditions. The evolution of the molecular weight during prolonged UV exposure is evaluated through SEC analysis, showing the effect of the benzophenone side groups, which promote crosslinking reactions. A crosslinking mechanism is proposed and demonstrated by means of 1H NMR and FT‐IR analyses. The gel content of the samples is measured after the UV exposure, demonstrating a correlation with the concentration of DOX‐derived units. Finally, water contact angle analyses are performed to investigate the effects of the fluorination degree on the wettability properties and thermal characterization is carried out. Moreover, rheological analyses show a shear thickening behavior for the copolymers with the highest concentration of DOX‐derived units.

Phlorotannin‐coated poly (ε‐caprolactone) film as a potential material for postsurgical adhesion prevention

AbstractPhlorotannins are known to possess several therapeutic properties such as anti‐inflammatory and anti‐oxidant effects, both of which are related to prevent tissue adhesion. Therefore, this study sought to fabricate phlorotannin‐coated PCL films for the prevention of post‐surgical adhesion. Phlorotannin‐coated PCL films were fabricated via the solvent casting and coating methods. After which the fabricated film was characterized using water contact angle analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and drug release ability analysis. Furthermore, the anti‐inflammatory and cell proliferation‐inhibiting properties of the fabricated film were assessed in LPS‐stimulated RAW264.7 macrophage cells and NHDF‐neo cells using the nitric oxide production assay, the WST‐1 assay kit, and Hoechst 33342 dye. The results indicated that the phlorotannin‐coated PCL film significantly inhibited nitric oxide production and reduced NHDF‐neo cell proliferation. These results suggest that phlorotannin‐coated PCL films constitute a promising anti‐adhesive bioactive compound with applicability in the field of DDSs.

Cheese whey mother liquor as dairy waste with potential value for polyhydroxyalkanoate production by extremophilic Paracoccus homiensis

The production of scl-polyhydroxyalkanoates homopolymers and heteropolymers by Paracoccus homiensis was investigated using cheese whey mother liquor (CWML) and cheese whey (CW). Our results showed that the analyzed strain was able to convert waste streams of dairy processing into biopolymers, reaching a maximum of 3.3 ± 0.31 g/L of cell dry mass (CDM) with 1.1 g/L of P(3HB-co-3 HV) copolymer (29.0% of CDM) at 72 h. CWML was the preferred substrate to achieve a high level of PHAs. Moreover, our data suggested that PHA content in the analyzed bacterial cells was stimulated by nitrogen deficiency when CWML was used. Whereas nutrients limitation did not enhance the PHA concentration in the cultivations supplmented with CW. We proved that the monomeric composition of extracted PHAs depended on the type of substrate, its concentration supplied and the culture media composition. Detailed characterization of the extracted PHAs biofilms using a differential scanning calorimetric, thermogravimetric and water contact angle analysis proved that they have useful material properties suitable for various applications. PHA production on dairy waste by Paracoccus species has not been reported so far. Taking into account the positive aspects of employing extremophiles in industrial biotechnology, Paracoccus homiensis is a very interesting halophilic bacterium for PHA production using cheese manufacturing wastes. Valorizing cheese whey mother liquor as the PHA production feedstock would be an excellent dairy processing waste management strategy.

Synergetic effect of absorber and condenser nano-coating on evaporation and thermal performance of solar distillation unit for clean water production

Two design modifications to increase the evaporation/condensation and freshwater yield of conventional solar stills (CSS) are presented – absorber coating with black paint (BP) in which 10 wt % reduced graphene oxide (rGO) was dispersed, and use of a nano-silicon-coated glass cover alongside the rGO coated absorber. Water contact angle analysis revealed that the hydrophilic glass/condenser hindered water droplet movement, whereas the hydrophobic silicon-coated glass enabled significantly faster water droplet movement. The rGO-coated absorber SS, with 99.2% solar absorptivity, improved the average water temperature by 11% leading to an augmented full-day freshwater yield of 3031 mL (versus 2160 mL for the CSS). The synergistic effect of the nano-silicon-coated glass and rGO-coated absorber further enhanced the full-day freshwater yield to 3410 mL. Energy/exergy analysis demonstrated enhanced efficiencies of the combined condenser and absorber coated SS of 37% (energy) and 112% (exergy), compared to the CSS. Non-linear characteristic equations described the instantaneous gain in energy efficiency of the combined absorber and condenser coated SS. Absorber/basin exhibited the highest rate of irreversibility in all three SS. The cost of water was 0.01 $/L for the dual-modified still. Water physicochemical quality analysis before and after desalination revealed that the purified water was suitable for drinking. • A solar still was fabricated with absorber and condenser coating for improved yield. • RGO coating improved the absorber average temperature by 10.9% compared to CSS. • Glass coated with nano-silicon altered condensation behavior to drop-wise from film-wise. • Modified SS showed augmentation in water yield compared to conventional SS. • Brackish water was converted into distilled water this is suitable for drinking.

Surface modification of polyetheretherketone (PEEK) to enhance osteointegration by grafting strontium Eucommia ulmoides polysaccharides

The complex bone regeneration microenvironment puts high demands on orthopedic implants. The implants are not only desired to satisfy the meeting of the biomechanical properties, but should also possess capabilities to promote osseointegration and bone immune regulation. PEEK is a promising polymeric material for bone implants due to its suitable mechanical properties that well match natural cortical bone tissue. However, its inert biological properties limit its application. As a newly-developed bioactive polysaccharides complex, strontium Eucommia ulmoides polysaccharides (EUP-Sr) has been proved to have capabilities including promoting osteogenesis and regulating bone immunity. In this study, in order to improve the bioactivities of PEEK, we introduce EUP-Sr to the PEEK surface via polydopamine-based coating and form a bioactive PEEK named DPEEK@EUP-Sr. The as-fabricated DPEEK@EUP-Sr was systematically investigated through scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle analysis to verify the successful introduction of EUP-Sr to PEEK, and in vitro biological experiments including cell proliferation and RT-PCR analysis suggested that the DPEEK@EUP-Sr can effectively promote the proliferation of preosteoblast MC3T3-E1, and exhibit significant anti-inflammation and osteogenesis effects, and so should be beneficial for osteointegration between bone and implants.

Preparation of adsorptive polyethyleneimine/polyvinyl chloride electrospun nanofiber membrane: Characterization and application

Landfilling and burning plastic waste, especially waste polyvinyl chloride (PVC), can produce highly toxic and carcinogenic by-products that threaten the ecosystem and human health. However, there is still a lack of proper methods for waste PVC recycling. Therefore, developing feasible ways for waste PVC recovery is urgently needed. The purpose of this study is to analyze the characteristics of PVC-based adsorptive nanofiber membranes and test their ability for the treatment of wastewater containing Cibacron Brilliant Yellow 3G-P, a widely used reactive dye. The polyethylenimine/polyvinyl chloride membrane (PEI/PVCM) was characterized by FTIR, FE-SEM, TGA, tensile analysis, water contact angle measurement, and zeta-potential analysis. The FTIR analysis confirmed that the PEI has successfully crosslinked with PVC. The FE-SEM images showed that the nanofibers constituting PEI/PVCM are compact with an average fiber diameter of 181 nm. The TGA results showed that the membrane was able to remain stable in wastewater below 150 °C. The average stress and strain of the PEI/PVCM were 7.64 ± 0.32 MPa and 934.14 ± 48.12%, respectively. The water contact angle and zeta potential analysis showed that after the introduction of PEI, the membrane converted from hydrophobic to hydrophilic, and the pHpzc was increased from 3.1 to 1.08. The pure water flux of the membrane was measured at 0.1 MPa and the result was 3013 ± 60 L/m2‧h. The wastewater purification capability of PEI/PVCM was measured at an initial dye concentration of 10 ppm and pH 4–9 at 0.1 MPa. The reusability of PEI/PVCM was verified through three adsorption-desorption cycles. The results demonstrated that the PEI/PVCM is a reusable membrane for efficient purification of wastewater containing reactive dyes over a wide pH range (pH 4–8).

Polyhydroxyalkanoates production from short and medium chain carboxylic acids by Paracoccus homiensis

The aim of this study was to evaluate an effect of short and medium chain carboxylic acids (CAs) rich stream derived from acidogenic mixed culture fermentation of acid whey on polyhydroxyalkanoates (PHAs) synthesis by Paracoccus homiensis and compare it with the impact of individual synthetic CAs. The obtained results confirmed that the analyzed bacterium is able to metabolize synthetic CAs as the only carbon sources in the growth medium with maximum PHAs production yields of 26% of cell dry mass (CDM). The replacement of the individual CAs by a CAs-rich residual stream was found to be beneficial for the Paracoccus homiensis growth. The highest biomass concentration reached about 2.5 g/L with PHAs content of 17% of CDM. The purified PHAs were identified as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by applying gas chromatography coupled with mass spectrometry, Fourier transform infrared spectroscopic spectra and UV–Vis spectra. Furthermore, a differential scanning calorimetric, thermogravimetric and water contact angle analysis proved that the extracted copolymers have useful properties. The obtained data are promising in the perspective of developing a microbial PHAs production as a part of an integrated valorization process of high CAs content waste-derived streams.

Poly (butylene adipate-co-terephthalate)/Sodium alginate blends have superior characteristics and can be used to fabricate vascular stents

To investigate the physical properties and in vitro biocompatibility of Poly (butylene adipate-co-terephthalate) and Sodium alginate (PBAT/SA) melt blending, as well as feasibility of using PBAT/SA blending materials to fabricate vascular stents through 3D printing technology. PBAT/SA composites were prepared by melt blending, and then related physical properties were assessed through FTIR, SEM, DSC, and water contact angle tests. The effects of the PBAT/SA blend on cell morphology, ROS, apoptosis, and cell proliferation were analyzed in vitro. In addition, we employed a 4-axis 3D printer to evaluate the feasibility of using PBAT/SA blend materials to fabricate vascular stents. We successfully prepared PBAT/SA melt blended materials. FTIR and SEM analyses demonstrated that PBAT and SA were compatible, while DSC data confirmed that the addition of SA improved the thermal properties of PBAT. Besides, water contact angle analysis showed that SA improved the hydrophilicity of PBAT. In addition, we successfully fabricated PBAT/SA vascular stent using 4-axis 3D printing technology. Our data showed that PBAT and SA are compatible, and the addition of SA enhances the thermal properties and hydrophilicity of PBAT. In addition, PBAT/SA blend materials can be fabricated into vascular stents using 4-axis 3D printing technology.

Low-temperature preparation of superhydrophilic coatings using tetraethoxysilane and colloidal silica by sol-gel method

In this study, a simple and facile method for producing superhydrophilic coatings by thermal curing at a low temperature of 100 °C or less for 2 h without a calcination process at high temperatures was reported. Hydrophilic coating solutions were prepared using tetraethoxysilane (TEOS) and colloidal silica as precursors by sol-gel method. After applying the prepared coating solution to a glass slide by dip-coating, a superhydrophilic coating was prepared by thermal curing at 100 °C for 2 h. In this process, the effect of the amount and concentration of colloidal silica added to the polysiloxane sol derived from TEOS on the superhydrophilicity of the coatings was observed. The coatings were characterized by water contact angle (WCA) analyzer, FT-IR spectroscopy, field emission scanning electron microscopy (FE-SEM), and atomic force microscope (AFM). In the coatings prepared using 10 wt% colloidal silica, as the content of colloidal silica added increased to 8 g, 16 g, 24 g, and 40 g, the WCA of the coating decreased to 56°, 37°, 10°, and 5°, respectively. From this result, it can be seen that a superhydrophilic coating, which shows a WCA of 5° or less, can be obtained when 40 g of colloidal silica is added. The FT-IR results suggest that the superhydrophilic coating consists of more hydrophilic components than the coating using only the polysiloxane sol without the addition of colloidal silica. In addition, the superhydrophilic coating showed a rough surface morphology in SEM and AFM observations. It was considered that the superhydrophilicity of the coating was derived from the increase of hydrophilic chemical components and surface roughness by adding colloidal silica. Moreover, the superhydrophilic coating showed an excellent anti-fogging property and a self-cleaning ability.

Surface Modification via Dielectric Barrier Discharge Atmospheric Cold Plasma (DBD-ACP): Improved Functional Properties of Soy Protein Film.

Atmospheric cold plasma (ACP), a novel technology, has been widely adopted as an efficient approach in surface modification of the film. The effect of ACP treatment on the physicochemical and structural properties of soy protein film were investigated. As a result, the optimal conditions for the preparation of the film were determined for soy protein (10%), glycerol (2.8%), ACP treatment at 30 kV for 3 min, on the basis of elongation at the break, and water vapor permeability. Under the optimal conditions, the ACP–treated films exhibited enhanced polarity according to the increased values of solubility, swelling index, and moisture content, compared with the untreated counterpart. An increase in the hydrophilicity is also confirmed by the water contact angle analysis, which decreased from 87.9° to 77.2° after ACP pretreatment. Thermostability was also improved by ACP exposure in terms of DSC analysis. SEM images confirmed the tiny pores and cracks on the surface of film could be lessened by ACP pretreatment. Variations in the Fourier transform infrared spectroscopy indicated that some hydrophilic groups were formed by ACP pretreatment. Atomic force microscopy data revealed that the roughness of soy protein film which was pretreated by ACP was lower than that of the control group, with an Rmax value of 88.4 nm and 162.7 nm for the ACP- treated and untreated samples, respectively. The soy protein film was characterized structurally by FT–IR and DSC, and morphological characterization was done by SEM and AFM. The soy protein film modified by ACP was more stable than the control group. Hence, the great potential in improving the properties of the film enables ACP treatment to be a feasible and promising alternative to other modification methods.

Construction of durable polyurea/polyvinylidene chloride composite film with high water vapor barrier property

Polyurea (PUA) is a type of protective coating material with excellent performance. However, the water vapor barrier property of PUA is not very ideal and need to be improved. In this study, PUA film was coated by polyvinylidene chloride (PVDC) by casting of PVDC emulsion, to improve its water vapor barrier property. A polydopamine layer was introduced between the PUA and PVDC layers to provide good adhesion performance. The morphology, chemical structure and performance of the films were characterized by scanning electron microscope, fourier transform infrared spectroscopy, water contact angle analysis, and water vapor transmission rate (WVTR) tests. It is indicated that, with the thickness of the PVDC coating increasing, WVTR decreases almost linearly. When the thickness of the PVDC coating is 5.2 μm, WVTR is 12.58 g/m2·day and water vapor permeability (WVP) is 1345.65 g·µm/m2·day·kPa. The WVTR and WVP of PVDC coated PUA is greatly reduced by 74.3% and 73.9% respectively, compared to that of pure PUA film. The adhesion of the PVDC coating on the PUA surface was evaluated through the cross-cut testing method. It is shown that the adhesion is strong enough to resist the pasting and peeling by adhesive tape.

Superiorly-hydrophilic chrysalis-like carbon-shell supported metallic Ni nanoparticles toward efficient oxygen reduction electrocatalysis

The combination of micro-scale architecture design and atomic-level interfacial engineering is of significant importance for developing advanced noble-metal-free catalysts toward efficient energy conversion. Herein, we report novel chrysalis-like hydrophilic-carbon-shell supported abundant metallic Ni nanoparticles (O-C@Ni) as a promising oxygen electrocatalyst toward electrochemical oxygen reduction reaction (ORR), which is derived from a unique organic-metal framework (MOF) based core-shell structure. Thanks to the superiorly hydrophilic affinity of oxygen-dopant-rich carbon-shell and the well-designed hollow architecture, this as-obtained O-C@Ni catalysts could deliver excellent ORR activity with a decent half-wave potential of 0.83 V and a small Tafel slope of 76 mV dec−1, comparable with commercial Pt/C catalysts and being one of the most active transition-metal based ORR electrocatalysts reported. In particular, robust methanol endurance and excellent electrocatalytic stability are evidently observed for O-C@Ni catalysts during a long-term ORR operation, superior to commercial Pt/C catalysts. X-ray absorption fine structure (XAFS) spectroscopy combined with water contact angle analyses reveals that the strong interfacial metal-support effect together with superiorly hydrophilic affinity enable O-C@Ni catalysts with promoted catalytic kinetics towards efficient ORR performance.

Photo- and thermo-responsive extracellular matrix mimicking nano-coatings prepared from poly(N-isopropylacrylamide)-spiropyran copolymer for effective cell sheet harvesting

Poly(N-isopropylacrylamide)-spiropyran (PNIPAAm-SP) copolymers were tethered onto the glass substrate using surface-initiated atom transfer radical polymerization (SI-ATRP). The substrate was previously activated by ultra-violet ozone (UVO) irradiation and the pre-synthesized initiator was immobilized on it. A block of PNIPAAm was grafted onto the glass substrates, followed by a second block of mixed NIPAAm and spiropyran acrylate (SPA). The effects of UVO irradiation time and polymerization time of spiropyran containing block on cell sheet formation and detachment characteristics were evaluated. The photo-responsiveness of SPA was evaluated by ultra-violet visible spectroscopy (UV–vis). The presence and thickness of the grafted polymer layers were evidenced by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM). The results of water contact angle (WCA) analysis showed that the modified surfaces became hydrophilic with decreasing temperature from 37 to 20 °C as well as with light irradiation. L929 mouse fibroblast cell culture results indicated a complete cell sheet formation. By applying temperature or light stimuli, the cell sheets were detached in a trypsin-free procedure.

Surface Modification of Polybenzimidazole (PBI) with Microwave Generated Vacuum Ultraviolet (VUV) Photo-oxidation

Background: Polybenzimidazole (PBI) is used in high temperature proton exchange membrane fuel cells (HT-PEMFCs) and redox flow batteries, where proton transfer occurs with the nitrogen-containing groups in PBI, and in aerospace applications exposed to oxygen and radiation. Objective: The objective is to investigate VUV photo-oxidation of PBI for the first time in order to incorporate polar functional groups on the surface to potentially enhance proton conductivity in HT-PEMFCs. Methods: A low-pressure microwave discharge of Ar generated 104.8 and 106.7 nm vacuum UV (VUV) radiation to treat PBI with VUV photo-oxidation. Analysis was done with X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), water contact angle (WCA) and Thermal Gravimetric Analysis (TGA) to detect changes in chemistry, surface roughness, hydrophilicity, and adhesion, respectively. Results : XPS showed: an increase in the O concentration up to a saturation level of 15 ± 1 at %; a decrease of the C concentration by about the same amount; and little change in the N concentration. With increasing treatment time, there were significant decreases in the concentrations of C-C sp2, C-C sp3 and C=N groups, and increases in the concentration of C=O, O-C=O, O-(C=O)-O, CN, and N-C=O containing moieties. The water contact angle decreased from 83° for pristine PBI down to 43°, making the surface more hydrophilic, primarily due to the oxidation, since AFM detected no significant changes in surface roughness. TGA analysis showed an improvement of water adhesion to the treated surface. Conclusion: Microwave generated VUV photo-oxidation is an effective technique for oxidizing the surface of PBI and increasing hydrophilicity.

Adsorption behavior of anthraquinones in deep eutectic solvent on polyester fiber and its application

Deep eutectic solvents (DESs can be used to facilitate the adsorption of anthraquinone dyes into polyester fabrics (PETFs) in facile conditions. The adsorption mechanism was investigated through a systematic characterisation study using methods including 1H nuclear magnetic resonance spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, water contact angle analysis, and tensile strength tests. It was found that anthraquinone dyes have different types of interactions with DESs, and that the adsorption and dyeing of PETF can be achieved only when the interactions between PETF and anthraquinones were stronger than those between the PETF and DESs. Additionally, the type of DES, hydrogen bond acceptor–hydrogen bond donor ratio, dye concentration, dyeing temperature, and dyeing time affect the adsorption and dyeing efficiency. In summary, PETF was successfully dyed with DES as a solvent, and the presence of DES did not destroy the PETF or significantly change its properties. Meanwhile, anthraquinone dyes affect the properties of PETF by forming non-covalent interactions. This study provides insights into problems encountered with adsorption and separation of target compounds in DESs, and provides the textile industry with a potentially much greener alternative that can reduce energy consumption and pollutant emissions, and avoid using toxic solvents for dyeing fabrics using DESs.

The predominant factor influencing cellular behavior on electrospun nanofibrous scaffolds: Wettability or surface morphology?

Several cues, including wettability, surface morphology, and porosity, affect the cellular behaviors on nanofibrous scaffolds. However, a challenging task is determining the more influential parameter on cellular behaviors. Herein, we prepared two sets of polycaprolactone (PCL)-based electrospun nanofibrous scaffolds, viz. surface morphology-altered PCL (SMA PCL) scaffolds and hydrophilic PCL-chitosan scaffolds with different chitosan content. We further investigated the scaffolds' cell attachment and proliferation ability to determine which is a predominant factor, wettability, or surface morphology? Water contact angle and alternative current impedance analyses revealed that incorporating chitosan to PCL increased the wettability and dielectric properties. In contrast, alterations in surface morphology did not show any significant changes to the properties mentioned above of neat PCL. Different solvent compositions (CHCl3/DMSO) caused cylindrical and smooth PCL nanofiber to adopt porous, wristed, or flat fibrous structures. The fibroblasts cell studies revealed that both PCL-chitosan and SMA PCL scaffolds had similar cell proliferation profiles on day 1. However, the former scaffolds showed a statistically significant difference from the latter ones on days 3 and 5. In conclusion, we suggest that increasing the wettability of nanofibrous scaffolds is more influential in directing cellular behaviors than surface morphology modification.

Effect of Biochar Addition on Mechanical Properties, Thermal Stability, and Water Resistance of Hemp-Polylactic Acid (PLA) Composites.

The present study investigated the effect of biochar (BC) addition on mechanical, thermal, and water resistance properties of PLA and hemp-PLA-based composites. BC was combined with variable concentration to PLA (5 wt%, 10 wt%, and 20 wt%) and hemp (30 wt%)-PLA (5 wt% and 10 wt%); then, composites were blended and injection molded. Samples were characterized by color measurements, tensile tests, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and water contact angle analysis. Experimental results showed that adding 5 wt% of BC enhanced the composite’s tensile modulus of elasticity and strength. Hence, the use of optimized loading of BC improved the mechanical strength of the composites. However, after BC addition, thermal stability slightly decreased compared with that of neat PLA due to the catalytic effect of BC particles. Moreover, the water-repelling ability decreased as BC content increased due to the specific hydrophilic characteristics of the BC used and its great porosity.

Butyl Group Distribution, Intestinal Digestion, and Colonic Fermentation Characteristics of Different Butyrylated Starches.

Despite being a promising butyrate carrier, butyrylated starch remains poorly understood in terms of the correlation between starch structure and fermentation characteristics. Herein, three butyrylated starches derived from different botanical sources were prepared with a similar degree of substitution. Raman microscopy and water contact angle analysis suggested that a relatively large proportion of butyl group substitutions occurred within the interior of butyrylated waxy maize starch (B-WMS) granules. In vitro digestion results showed that branch points provided butyl groups with a specific protection from enzymatic hydrolysis, whereas butyl groups significantly increased the resistant starch content of butyrylated starch. Moreover, the porous morphology with less distributed butyl groups on the granular surface contributed to a faster fermentation rate in B-WMS. The current study reveals the influence of botanical origin on butyl group distribution, which in turn plays a pivotal role in regulating the intestinal digestion and colonic fermentation of butyrylated starch.

Novel antibacterial and antifouling PES nanofiltration membrane incorporated with green synthesized nickel-bentonite nanoparticles for heavy metal ions removal

• The nickel-bentonite nanoparticles (NBNPs) were synthesized using plant extract. • The NBNPs were used to modifying the polyethersulfone membrane. • The modified membranes exhibited significant water flux and antifouling properties. • The NBNPs/PES membranes showed high rejection of heavy metal ions than PES. • The NBNPs/PES membranes exhibited desirable antibacterial activity. Lack of water resources and water pollution by heavy metal ions and microorganisms has made it necessary to utilize efficient water treatment methods. In this study, for the first time, nickel-bentonite nanoparticles (NBNPs) were synthesized using Scrophularia striata extract. NBNPs were used as novel nanofillers to fabricate antifouling and antibacterial NBNPs/polyethersulfone (PES) nanofiltration membranes via the phase inversion method for heavy metal ions rejection. NBNPs were characterized by FT-IR, XRD, zeta potential, EDS, FESEM, and TEM. The fabricated membranes were characterized using FT-IR, XRD, EDS, SEM, water contact angle, zeta potential, and porosity analyses. The results showed improvement of hydrophilicity, surface charge, and porosity for the modified membranes. The blended membranes had substantially less fouling and higher heavy metal ions rejection than the unmodified membrane. Pure water flux of the unfilled PES membrane was enhanced from 15 to 34.4 and 58.8 kg/m2h for 0.1 and 0.5 wt% of NBNPs, respectively. The flux recovery ratio was increased from 38.3% for the unmodified membrane to 98.2% for 0.5 wt% NBNPs/PES membrane. Also, 0.5 wt% NBNPs/PES membrane exhibited the best rejection performance (Zn2+: 98.62%, Cu2+: 97.88% and Pb2+: 97.03%). Evaluation of antibacterial properties of the membranes against Escherichia coli and Staphylococcus aureus was performed. The modified membranes had significant antibacterial capability and 1 wt% NBNPs/PES membrane exhibited the highest antibacterial rate. According to the findings, NBNPs could be used as nanofillers to fabricate modified nanofiltration membranes for heavy metal ions rejection and antibacterial ability.

Tailoring the Everolimus Immobilisation Time on Poly(L-Lactic Acid/ Poly(D-Lactic Acid) Scaffold for Biodegradable Stent Coating Development

Biodegradable stents (BDS) are projected to be degraded while supporting the blood vessel lumen. Equipping BDS with coated drugs will enhance its biological properties. In this study, everolimus drug was coated on poly (L-lactic acid) (PLLA)/poly (D-lactic acid) (PDLA) scaffolds by utilising polydopamine (PDA) as an intermediate layer. The immobilisation time for the coating process was tailored at 12 and 24 hours. The effects of different immobilisation time of everolimus (12 and 24 hours) were characterised through an ATR-FTIR, SEM and water contact angle analyses to investigate the chemical functionalities, surface morphology and hydrophilicity properties, respectively. The ATR-FTIR results indicated the presence of chemical functionalities of the coating and the scaffolds. The scaffold surfaces were having a transition from smooth to irregular surfaces after the PDA grafting and the coating of everolimus. More homogeneous surface formation was observed and greater hydrophilicity was recorded on the PLLA/PDLA scaffolds coated with everolimus at 24 hours immobilisation compared to the 12 hours immobilisation. These findings are beneficial for the fabrication of BDS with the implementation of everolimus and PDA as coating materials.