Incorporation Of Silica Nanoparticles Research Articles

Effect of dual dispersion of carbon fiber and silica nanoparticles on recovery performance of shape memory epoxy

Shape memory polymers are utilized in diverse fields, including deployable structures and components, owing to their advantageous properties like low density, cost-effectiveness, and ease of processing. The current study investigates the effect of dual dispersion of carbon fibers (CF) and silica nanoparticles (SN) on the recovery performance of shape memory epoxy composites. CF (0.25 wt.%) reinforced epoxy composite, SN (0.25 wt.%) reinforced epoxy composite, and dual (CF and SN 0.25 wt.% each) dispersed epoxy composite were developed using magnetic stirring and ultrasonic mixing to study the mechanical properties and shape memory behaviour. Flexural strength, tensile strength and fracture toughness of pristine epoxy was found to be 134.38, 52.15 MPa and 1.91 MPa∙m1/2, respectively. The addition of CF resulted in a flexural strength of 135.70 MPa and a tensile strength of 53.01 MPa, while the incorporation of SN led to a flexural and tensile strength of 138.40 and 53.69 MPa, respectively. The fracture toughness of composites after adding CF and SN was found to be 2.22 and 2.39 MPa∙m1/2, respectively. With dual dispersion, the flexural strength of 139.82 MPa, tensile strength of 54.64 MPa, and fracture toughness of 2.75 MPa∙m1/2 were achieved. Dual dispersion has shown improved mechanical properties compared to single dispersion. The introduction of CF slightly decreased the shape fixity ratio (Rf ) and shape recovery ratio (Rr ) of the pristine epoxy from 98.67% and 96.62% to 96.67% and 95.15%, respectively. Similarly, the addition of SN further reduced these ratios to 98.00% and 91.83%, respectively. With a dual dispersion approach Rf and Rr were observed to be about 97.33% and 93.83%, respectively. The addition of fillers led to a reduction in Rf and Rr due to inhibition of polymeric chains, resulting in partial shape recovery. However, recovery time improved from 28 to 23 and 26 s with addition of CF and SN, respectively, in epoxy. With dual dispersion, a speedy recovery was achieved with a recovery time of 21 s. The findings of this study demonstrate the potential of dual dispersed fillers to improve the mechanical and shape memory properties of epoxy, which could find applications in the smart materials and structural engineering.

All‐Printed Electrically Driven Lighting via Electrochemiluminescence

AbstractElectrochemiluminescence (ECL) has attracted significant attention as a promising light‐emitting technology owing to its simple configuration and solution processability. ECL has wide applications in biological and chemical sensors, lighting, and displays. ECL lighting devices are fabricated as sandwiched structures with a transparent electrode on top, which limits their widespread adoption. Intricate structures with high precision and customizable designs can be directly fabricated using 3D printing. However, 3D printing of ECL devices is challenging because of poor printability and structural integrity of ECL luminophore inks. Here, all‐printed electrically driven lighting is demonstrated using the direct ink writing method. The ECL reactive layer and electrodes are directly printed using a side‐by‐side electrode configuration. A 3D printable ECL ink is developed by incorporating silica nanoparticles as rheological modifiers to realize well‐defined patterns with high structural integrity. Graphene is introduced on Ag multilayer electrodes to embrace both the electrical conductivity and electrochemical stability for efficient ECL operation. This all‐printing approach allows the fabrication of ECL devices with complex designs, such as combs and spirals. Moreover, it facilitates seamless printing on various substrate materials, making this technology an asset in the fields of biology, chemistry, and electronics.

Mitigating CO2 emanations within the marine concrete industry with different structures of silica nanoparticles

The extensive utilization of marine concrete results in a significant consumption of cement, thereby leading to an increase in CO2 emanations. Enhancing the potency and longevity of marine concrete serves as an efficacious approach to mitigate CO2 emanations. The objective of this investigation was to introduce colloidal silica nanoparticles with distinct three-dimensional structures (MCM-41, SBA-15, and DFNS) for the purpose of enhancing the mechanical functionality and longevity of remarkable sulfate persistence Portland cement. Meantime, the incorporation of silica nanoparticles with distinct three-dimensional architectures (DFNS, MCM-41, and SBA-15) into marine cement mortar was carried out, and an investigation was conducted on the aggregation of silica nanoparticles, as well as the humidifying process and micro-process of the mortar. According to the findings, the addition of silica NPs improved the resilience, mechanical traits, and longevity of the marine cement cases. When the inclusion of silica nanoparticles with varying three-dimensional structures (DFNS, MCM-41, and SBA-15) was implemented, a decrease in both the chloride diffusion coefficient and porosity was observed. The compressive intensity of cement mortar was enhanced in the presence of DFNS, MCM-41, and SBA-15 when compared to control samples, following a rehabilitating period of 5, 15, and 30 days. These advancements in intensity and longevity suggest that DFNS exhibits considerable potential in mitigating CO2 emanations within the marine concrete industry.

Incorporating Nanoparticles in Porous Foam Templating for Enhanced Sensitivity of Capacitive Pressure Sensors

AbstractCapacitive pressure sensors based on porous foams have been demonstrated for various biomedical applications (0–10 kPa). Many different methods for fabricating porous foams have been reported. In this work, for the first time, the incorporation of silica nanoparticles are reported into the templating process of porous foams fabricated through a combination of particle and emulsion templating, in order to enhance the formation of smaller microstructures in polydimethylsiloxane foams. The foams are coated with graphene, and pressure sensors developed using these foams showed increased sensitivity, up to 4.08 kPa−1. The incorporation of nanoparticles also improves the linearity of the sensitivity, giving a linear sensitivity for the pressure sensors over a pressure range of 0–6 kPa. Further, these pressure sensors have a low limit of detection of ≈13 Pa. These results indicate that incorporation of suitable nanoparticles in the templating of foams is a promising strategy for developing foam‐based pressure sensors with high and linear sensitivity.

The relationship between cellular microstructure and the mechanical properties of styrene/methyl methacrylate copolymer‐silica nanocomposite foams prepared by a supercritical CO2 blowing agent

AbstractStyrene/methyl methacrylate (St/MMA) copolymer‐silica nanocomposite foams were prepared using supercritical CO2 as blowing agent, and the relationships between their cellular microstructure and mechanical properties were investigated. The effects of nanosilica content, size, and surface chemistry on the foam's microstructure and properties were examined. Dispersion and distribution of silica nanoparticles with different surface chemistry in St/MMA copolymer nanocomposites were discussed. To determine the most suitable copolymer composition for incorporating silica nanoparticles, some operating conditions such as temperature and pressure were primarily examined to study their effects on the microstructure of resulting foams. In compressive mechanical properties of final foams, a considerably high value was obtained for the compressive strength of the foams of up to 9.5 MPa. The prepared low‐density (below 0.2 g/cm3) St/MMA copolymer microcellular foams can be used in green lost foam iron casting processes.Highlights Styrene/methyl methacrylate copolymer‐silica nanocomposite foams were prepared via supercritical CO2. Foams' cell size was changed by changing silica nanoparticle surface chemistry and size. The uniform cellular microstructure was achieved by nanosilica size increment. Increasing nanoparticle size improved the foam's mechanical properties. Low‐density foams were achieved for potential application in lost foam casting.

Improving The Mechanical Properties of Carbon-epoxy And Glass-epoxy Composites by Incorporating Silica Nanoparticles

Improving The Mechanical Properties of Carbon-epoxy And Glass-epoxy Composites by Incorporating Silica Nanoparticles

Hydrochromic film for dynamic information storage using cellulose nanofibers and silica nanoparticles

A hydrochromic composite film was fabricated by incorporating silica nanoparticles (SiNPs) with cellulose nanofibers (CNFs). The CNF/SiNP composite film underwent a reversible change in transparency in response to external moisture variation. The CNFs improved the dimensional stability of the CNF/SiNP composite film and induced morphological differences in SiNP agglomerates, which control the water vapor condensation in a porous film. The condensed water in the pores reduced the difference in refractive index over the CNF/SiNP film, enhancing its transparency. The selective transparency of the composite film was challenged by printing CNF/SiNP inks at different composition ratios. The differing susceptibility of the printed patterns to moisture provided selective transparency at specific patterns, which can store dynamic information such as QR or numerical codes by simple water vapor adsorption and desorption.

An investigation of the performance of polyamide membrane for the concentration of pomegranate and effect on the physical and sports health of patients with physical weakness: A novel study

The purpose of fruit juice concentration is not only to prevent microbiological spoilage and chemical changes but also to cater to health and sport-related considerations such as nutritional value and athletic performance. Concentrated fruit juice is commonly used as a source of natural sugars, vitamins, and minerals in sports beverages and recovery drinks. In this study, the use of reverse osmosis (RO) as a method for thickening peach juice offers advantages in terms of preserving the nutritional content of the juice. By avoiding chemical reactions and requiring less energy, RO helps to retain the beneficial compounds present in the fruit juice, which are essential for supporting overall health and providing hydration during physical activities. The incorporation of silica nanoparticles in the polymer membrane used for the RO system can have additional health benefits. Silica nanoparticles have been investigated for their potential in enhancing nutrient absorption and promoting cellular health. By utilizing these nanoparticles in the membrane, the concentration process not only achieves the desired thickness but also has the potential to enhance the bioavailability of the nutrients present in the peach juice. Furthermore, the optimization of the RO system using statistical methods and software contributes to the efficiency and effectiveness of the concentration process. This optimization ensures that the desired concentration and flux are achieved, which is crucial for maintaining the desired taste, texture, and nutritional composition of the final fruit juice product. The use of RO and the incorporation of silica nanoparticles in fruit juice concentration have implications for both health and sport, offering a means to preserve the nutritional value of the juice while catering to the needs of athletes and individuals engaged in physical activities. Fruit juice can provide hydration and carbohydrates for athletes, supporting their health and athletic performance.

Experimental evaluation of mechanical properties and microstructure for recycled aggregate concrete collaboratively modified with nano-silica and mixed fibers

The present study was conducted to meet the demand of the construction schedule for emergency repair and construction in special projects by using the recycled aggregates produced by mechanically crushing the demolished materials on-site. The study aims to modify recycled aggregate concrete (RAC) by incorporating silica nanoparticles (NS) and mixed fibers together to meet the needs of the above special project. Here, the properties of 21 kinds of concrete with different NS contents and mixed proportions of fibers were tested, including their fresh properties, hardening properties and microstructure. Their working properties in the fresh state were studied by measuring slump and unit weight; while the mechanical properties after hardening were mainly evaluated in terms of compressive strength, splitting tensile strength, modulus of elasticity and flexural strength, and here the flexural toughness as well as the residual strength of the specimens were calculated using two methods. In addition, the effects of different NS contents, steel fibers and polyvinyl alcohol (PVA) fibers on crack development and water absorption were investigated in the microstructure. The pores between the cement matrix, interfacial transition zone (ITZ) and fibers and how they are alteredby NS were characterized by SEM and 3D-CT scans. All these results indicate that NS content has a significant effect on both the workability and mechanical properties of RAC, that steel fibers are beneficial to improve the overall mechanical index of RAC, while PVA fibers have a limited enhancement effect, and that NS particles in the microstructure help to fill the pores of 0.001–0.01 mm3 volume in the cement matrix and improve the performance of the ITZ.

Incorporation of silica nanoparticles into porous templates to fabricate mesoporous silica microspheres for high performance liquid chromatography applications

High-performance liquid chromatography is one of the most important analytical tools for the identification and separation of substances. The efficiency of this method is largely determined by the stationary phase of the columns. Although monodisperse mesoporous silica microspheres (MPSM) represent a commonly used material as stationary phase their tailored preparation remains challenging. Here we report on the synthesis of four MPSMs via the hard template method. Silica nanoparticles (SNPs) which form the silica network of the final MPSMs were generated in situ from tetraethyl orthosilicate (TEOS) in the presence of (3-aminopropyl) triethoxysilane (APTES) functionalized p(GMA-co-EDMA) as hard template. Methanol, ethanol, 2-propanol, and 1-butanol were applied as solvents to control the size of the SNPs in the hybrid beads (HB). After calcination, MPSMs with different sizes, morphology and pore properties were obtained and characterized by scanning electron microscopy, nitrogen adsorption and desorption measurements, thermogravimetric analysis, solid state NMR and DRIFT IR spectroscopy. Interestingly, the 29Si NMR spectra of the HBs show T and Q group species which suggests that there is no covalent linkage between the SNPs and the template. The MPSMs were functionalized with trimethoxy (octadecyl) silane and used as stationary phases in reversed-phase chromatography to separate a mixture of eleven different amino acids. The separation characteristics of the MPSMs strongly depend on their morphology and pore properties which are controlled by the solvent during the preparation of the MPSMs. Overall, the separation behavior of the best phases is comparable with those of commercially available columns. The phases even achieve faster separation of the amino acids without loss of quality.

Electrospun Silica-Polyacrylonitrile Nanohybrids for Water Treatments.

In this work, the removal of NOM (natural organic matter) as represented by humic acid by means of electrospun nanofiber adsorptive membranes (ENAMs) is described. Polyacrylonitrile (PAN) was used for the preparation of ENAMs incorporating silica nanoparticles as adsorbents. The addition of silica to the polymer left visible changes on the structural morphology and fibers' properties of the membrane. The membrane samples were characterized by pure water permeability, contact angle measurement, SEM, XPS, and XRD. This study assesses the preliminary performance of PAN-Si membranes for the removal of natural organic matter (NOM). The membrane rejected the humic acid, a surrogate of NOM, from 69.57% to 87.5%.

Electro-conductive silica nanoparticles-incorporated hydrogel based on alginate as a biomimetic scaffold for bone tissue engineering application

An innovative electrically conductive hydrogel was fabricated through the incorporation of silica nanoparticles (SiO2 NPs) and poly(aniline-co-dopamine) (PANI-co-PDA) into oxidized alginate (OAlg) as a biomimetic scaffold for bone tissue engineering application. The developed self-healing chemical hydrogel was characterized by FTIR, SEM, TEM, XRD, and TGA. The electrical conductivity and swelling ratio of the hydrogel were obtained as 1.7 × 10−3 S cm−1 and 130%, respectively. Cytocompatibility and cell proliferation potential of the developed scaffold were approved by MTT assay using MG-63 cells. FE-SEM imaging approved the potential of the fabricated scaffold for hydroxyapatite (HA) formation and bioactivity induction through immersing in SBF solution.

Stiffness enhancement of magnetorheological foam by structural modification using silica nanoparticles additive

Magnetorheological (MR) foam is a newly developed porous smart material that is able to change its properties continuously, actively, and reversibly in response to controllable external magnetic stimuli. Unfortunately, the stiffness or also known as storage modulus of MR foam is still rather low and insufficient, in the range of below 100 kPa only, due to weak interparticle interaction between CIPs and the foam matrix, which consequently restricts the potential of MR foam to be used in future sensor applications or in other semi-active devices. Therefore, the aim of this research is to enhance the structural and storage modulus of MR foam by adding silica nanoparticles as an additive. Consequently, MR foam samples with different compositions of silica nanoparticles in the range of 0–5 wt% were prepared via an in situ method. The rheological properties were tested under an oscillatory shear mode with the absence and presence of magnetic fields using a rheometer, with the input parameters of strains between 0.001% and 10% and range of magnetic flux density between 0 and 0.73 T for a magnetic field sweep test. The rheological findings show that with the addition of silica nanoparticles, particularly at 4 wt%, have enhanced the storage modulus of MR foam by 260%, which attributed to the highest stiffness from 45 to 162 kPa. Meanwhile, the change of storage modulus under the influence of magnetic fields (0 T–0.73 T) somehow showed small increment, about ∆1 kPa for each concentration of silica nanoparticles in MR foams, due to non-magnetic behavior of silica. The morphological characteristics of MR foams were described by an elemental analysis carried out by a using variable pressure scanning electron microscope (VPSEM) equipped with energy dispersive x-ray spectroscopy (EDX). The micrographs demonstrated large open-cell pores for MR foam, while MR foam with silica nanoparticles exhibited more closed-cell pores, associated with the enhancement of its storage modulus. It indicates that the silica nanoparticles have encouraged well dispersion of the particles in the foam matrix, which improved and strengthened the microstructure of MR foams through formation of silane coupling bonds of silica in the filler-matrix structure. Overall, incorporation of silica nanoparticles as an additive in the MR foam could provide advantage in enhancing the structure and mechanical properties of MR foam, for various future smart devices.

Self-assembly dynamics and effect on synthetic nanobio-optical properties by hybrid monocolored silica nanoparticle labeling of Escherichia coli

The deposition of silica nanoparticles on Escherichia coli bacteria was investigated. The noncovalent interaction between the silanized surfaces and polar components of the biomembrane resulted in a nanobiostructure. This hybrid architecture showed stable conformation characteristics evaluated with different microscopy techniques, such as bright field confocal microscopy and transmission electron microscopy (TEM). Nanobioarchitectures were detected within colloidal dispersions and in the absence of aqueous media. Nanobiointeractions were related to strong polar and hydrogen bridges’ noncovalent interactions. Thus, well-constituted and defined nanobiostructures were observed by bright field confocal microscopy and TEM after their preparation in optimal conditions. However, to evaluate their stability and internanobiostructure interactions, size distributions within variable periods were determined. Variable nanobioaggregate sizes were recorded according to nanoparticles and bacteria concentrations. From single nanolabeled E. coli with well dispersible properties, low bacteria concentrations were observed. In intermediate and high concentrations, different distributions of nanobiostructures were observed in different periods. It was observed that the incorporation of silica nanoparticles into E. coli increased their dispersibility; however, their modified E. Coli membranes with silanized nanosurfaces augmented their internanobiostructure interactions through time. Here, we discuss the dynamics and nanobio-optics properties of E. coli. Their nanobiostructures could not be considered to be static systems; their interactions are regarded as important factors for dispersibility, stability, and effects against additional chemical agents such as antibiotics.

Temperature Dependent on Mechanical and Rheological Properties of EPDM-Based Magnetorheological Elastomers Using Silica Nanoparticles.

Temperature is one of the most influential factors affecting the performance of elastomer matrix in magnetorheological elastomer (MRE). Previous studies have utilized silica as a reinforcing filler in polymer composite and as a coating material in MRE to improve the thermal stability of the base material. However, the usage of silica as an additive in the thermal stability of MRE has not been explored. Thus, in this study, the effect of silica as an additive on the temperature-dependent mechanical and rheological properties of ethylene propylene diene monomer (EPDM)-based MREs was investigated by using 30 wt.% carbonyl iron particles (CIPs) as the main filler, with different contents of silica nanoparticles (0 to 11 wt.%). The microstructure analysis was examined by using field-emission scanning electron microscopy (FESEM), while the thermal characterizations were studied by using a thermogravimetric analyzer and differential scanning calorimetry. The tensile properties were conducted by using Instron Universal Testing Machine in the absence of magnetic field at various temperatures. Meanwhile, the rheological properties were analyzed under oscillatory loadings in the influence of magnetic field, using a rotational rheometer at 25 to 65 °C. The results revealed that the temperature has diminished the interfacial interactions between filler and matrix, thus affecting the properties of MRE, where the tensile properties and MR effect decrease with increasing temperature. However, the presence of silica capable improved the thermal stability of EPDM-based MRE by enhancing the interactions between filler and matrix, thus reducing the interfacial defects when under the influence of temperature. Consequently, the incorporation of silica nanoparticles as an additive in EPDM-based MRE requires more exploration, since it has the potential to sustain the properties of MRE devices in a variety of temperature conditions. Thus, the study on the temperature-dependent mechanical and rheological properties of MRE is necessary, particularly regarding its practical applications.

Electrospun nanofibrous polyether-block-amide membrane containing silica nanoparticles for water desalination by vacuum membrane distillation

In this work, hydrophobic nanofibrous membranes based on polyether-block-amide (PEBAX-2533) were prepared by the electrospinning technique for using in the vacuum membrane distillation (VMD) process for water desalination applications. In the first part of this study, the influence of the electrospinning conditions like polymer concentration, surfactant concentration, applied voltage, spinneret to collector distance, feed injection rate and spinneret diameter on the morphology of the electrospun mats was investigated and optimized to obtain uniform, bead-less and defect-free nanofibrous PEBA membranes. In the second part, the electrospun nanofibrous SiO2/PEBAX-2533 membranes were fabricated by incorporating silica nanoparticles into the polymer solution. The morphology, structure, and surface properties of the prepared nanofibrous SiO2/PEBA membranes were characterized by the SEM, FTIR, OCA, and tensile strength tests. Likewise, the VMD performance of the prepared electrospun SiO2/PEBA membranes was studied for the desalination of NaCl aqueous solutions at various operating conditions. It was observed that the VMD performance of the prepared electrospun nanofibrous SiO2/PEBAX-2533 membrane containing 8 wt% of silica nanoparticles had the best separation performance in terms of the water flux, flux decline and TDS content of the permeate stream. Finally, a comparison between the prepared nanofibrous SiO2/PEBAX-2533 membrane and a commercial PVDF membrane revealed that the VMD separation performance and long-term stability of the electrospun membrane were much better than those of the commercial PVDF membrane.

Effects of silica on mechanical and rheological properties of EPDM-based magnetorheological elastomers

Magnetorheological elastomers (MREs) are a kind of emerged smart material, where its responsive moduli in terms of mechanical and rheological properties are largely influenced by the presence of an external magnetic field. However, the incompatibility on the surface properties of its raw materials (fillers and matrix) may deteriorate the required properties of MREs. Therefore, in this study, the innovation of MRE by embedding silica nanoparticles as an additive has been experimentally investigated to strengthen the interactions between filler and matrix, thus resulted in enhancement of mechanical and rheological properties of MRE. The ethylene propylene diene monomer (EPDM)-based MREs were fabricated by mixing the EPDM with carbonyl iron particles (CIPs) as the main filler and different contents of silica nanoparticles (0 wt%–11 wt%) as an additive. The microstructures, magnetic properties and tensile properties of isotropic EPDM-based MREs were observed by using field emission scanning electron microscopy, vibrating sample magnetometer and Instron Universal Testing Machine, respectively. Meanwhile, the rheological properties were examined under oscillatory loadings in the absence and presence of magnetic field using rotational rheometer. The experimental results showed that the silica nanoparticles play a significant role in improving the properties of EPDM-based MREs. The adhesiveness of silica into CIPs has amended the interfacial interactions between CIPs and matrix by occupying the gaps between distributed CIPs within the MRE. Consequently, the addition of 11 wt% silica has not only improved the tensile properties (tensile strength and elongation at break), but also enhanced the MR effect compared to EPDM-based MREs without silica. Thus, incorporation of silica nanoparticles as an additive in EPDM-based MRE has the potential to be further explored and compromised to bring new innovation in real engineering applications.

Effects of Dietary Silica Nanoparticle on Growth Performance, Protein Digestibility, Hematology, Digestive Morphology, and Muscle Composition of Nile Tilapia, Oreochromis Niloticus

The use of nanotechnology in food production systems is being investigated globally, though there is limited research on its effect on fish nutrition. Therefore, this study aimed to identify the effects of silica nanoparticles (NPs) on the nutrition and physiology of tilapia, Oreochromis niloticus. Four isonitrogenous diets (300 g/kg crude protein) with NPs (0, 1, 2, and 3 mg/kg diet) were fed to fish (6.52 ± 0.20 g) in a recirculatory aquaculture system for 56 days. Throughout the study period, the effects of silica NP on survival rate, blood cell count, hemoglobin (Hb) level, condition factor (CF), and final product composition (except lipid content) were insignificant. However, growth performance and feed efficiency increased with an increasing level of silica NP, up to 2 mg/kg, and then decreased. This increase was due to the highest apparent protein digestibility and dry matter digestibility when fish were fed silica NP at 2 mg/kg. However, fish at the early stage showed better performance in all dietary groups than in later. Blood glucose (BG) content and histology of the kidney revealed that fish were stressed when a 3 mg/kg silica NP was used and they adapted through excessive excretion via expanded glomeruli. Though no significant effect on villi length was observed, silica NP increased the surface area widening the villi of the gut along with the number of goblet cells in the intestine significantly, when supplemented at a level of 2 mg/kg. The bioaccumulation of silica shows that incorporating silica NP in the fish feed will not compromise human health safety upon consumption. Although silica NP at 1 mg/kg and 3 mg/kg yielded some improvements to growth and final product quality, a 2 mg/kg silica NP generated the best results in all measured parameters.

Bifunctional poly (l-lactic acid)/hydrophobic silica nanocomposite layer coated on magnesium stents for enhancing corrosion resistance and endothelial cell responses

Biodegradable magnesium (Mg)-based vascular stents can overcome the limitations of conventional permanent metallic stents, such as late in-stent restenosis and thrombosis, but still have difficulty retarding degradation while providing adequate mechanical support to the blood vessel. We incorporated silica nanoparticles surface-functionalized with hexadecyltrimethoxysilane (mSiNP) into a poly (l-lactic acid) (PLLA) coating as a physical barrier to disturb the penetration of the corrosive medium as well as a bioactive source that releases silicon ions capable of stimulating endothelial cells. The corrosion resistance and biocompatibility of this bifunctional PLLA/mSiNP nanocomposite coating were investigated using different weight ratios of mSiNP. The nanocomposite coating containing more than 10 wt% of the mSiNP (PLLA/10mSiNP and PLLA/20mSiNP) significantly delayed the corrosion of the Mg substrate and exhibited favorable endothelial cell responses, compared to the pure PLLA coating. Specifically, the calculated corrosion rates of PLLA/10mSiNP and PLLA/20mSiNP decreased by half, indicating the durability of the coating after immersion in simulated body fluid for 12 days. Based on the in vitro cellular response, the incorporation of the mSiNPs into the PLLA coating significantly improved the endothelial cell responses to the Mg substrate, showing better initial cell surface coverage, migration, and proliferation rate than those of pure PLLA. These results indicate that the PLLA/mSiNP nanocomposite coatings have significant potential to improve the corrosion resistance and vascular compatibility of biodegradable Mg-based vascular stents.

Nanofiltration Composite Membranes Based on KIT-6 and Functionalized KIT-6 Nanoparticles in a Polymeric Matrix with Enhanced Performances.

The nanofiltration composite membranes were obtained by incorporation of KIT-6 ordered mesoporous silica, before and after its functionalization with amine groups, into polyphenylene-ether-ether-sulfone (PPEES) matrix. The incorporation of silica nanoparticles into PPEES polymer matrix was evidenced by FTIR and UV–VIS spectroscopy. SEM images of the membranes cross-section and their surface topology, evidenced by AFM, showed a low effect of KIT-6 silica nanoparticles loading and functionalization. The performances of the obtained membranes were appraised in permeation of Chaenomeles japonica fruit extracts and the selective separation of phenolic acids and flavonoids. The obtained results proved that the PPEES with functionalized KIT-6 nanofiltration membrane, we have prepared, is suitable for the polyphenolic compound’s concentration from the natural extracts.