Porous Nanocomposite Materials Research Articles

Investigating the bending and buckling behaviors of composite porous beams reinforced with carbon nanotubes and graphene platelets using a TRPIM path following mesh-free approach

The aim of the present work consists in investigating the nonlinear behavior of porous beams reinforced with graphene platelets (GPL) and supported carbon nanotubes (CNT), termed functionally graded graphene platelets reinforced composite beam (FG-GPLRC) and functionally graded nanotube carbon reinforced composite beam (FG-CNTRC), respectively. Notably, the distribution of GPL/CNT is explored in both uniform and non-uniform patterns across the beam's thickness. What sets this research apart is its utilization of a refined beam model as enhanced FSDT incorporating nonlinear shear terms which is a crucial advancement in accurately capturing the post-buckling response in certain boundary conditions, a feature lacking in the existing FSDT literature. Innovatively, the post-buckling load-deflection relationship is derived through the solution of governing equations incorporating cubic nonlinearity. This is achieved by employing Galerkin's method alongside a non-iterative high-order continuation technique based on the asymptotic numerical method coupled with the Tchebychev-radial point interpolation method (TRPIM), using a path-following where the solutions are obtained branch-by-branch by eliminating the need for iterative processes. In essence, this research underscores the pivotal role of porosity and GPL/CNT reinforcement in shaping the post-buckling configuration of both perfect and imperfect nanocomposite beams, thereby advancing our understanding of structural behavior in porous nanocomposite materials. The findings of this study illuminate the significant influence of parameters such as porosity coefficient, porosity distribution, GPL/CNT distribution, and GPL-weight/CNT-volume fraction on the nonlinear buckling behavior of porous beams.

Nanocomposite scintillation perovskite-delignified wood photonic guides for X-ray imaging

Nanocrystalline scintillators with low-cost, fast response, and high light yield are widely used for X-ray imaging. However, they fail in high-energy X-ray imaging because of the fundamental limitations due to lateral radiation spreading in thicker device-compatible active layers. This issue is resolved by using the novel nanocomposite containing CsPbBr3 scintillation single-microcrystalites embedded into transparent, natural wood-derived light-guiding fibrous structures. The CsPbBr3 crystals convert X-ray to visible photons with a high photoluminescence quantum efficiency (76 %), and an average fast photoluminescence decay time of 25.9 ns. The delignified wood-derived fiber-like lumina effectively guide light, while suppressing the lateral spreading of scintillation photons. This unique porous nanocomposite material offers an excellent X-ray detection performance, and linear response in a wide parameter range. The developed scintillator screen achieves well-resolved, high-contrast X-ray imaging, featuring a very high spatial resolution of 11.9 lp/mm at a modulation transfer function of 0.2, thus exceeding the benchmark industry standards and offering a new advanced materials platform for radiation detection and dosimetry applications.

Fabrication of a novel superhydrophobic cotton by HDTMS with TiO2 supported activated carbon nanocomposites for photocatalysis and oil/water separation

The strong superhydrophobic and photocatalytic cotton was fabricated by a simple one-step dip rolling technique using activated carbon supported titanium dioxide (TiO2) composite with fluoride-free hexadecyltrimethoxysilane (HDTMS) coupling agent. The experimental result shows that the contact angle of cotton fabric treated with TiO2-AC/HDTMS reaches 158°. More importantly, 0.7 g TiO2-AC provided the same superhydrophobic effect as 5 g TiO2. Moreover, the surface physical morphology and chemical composition of modified cotton fabric were observed via scanning electron microscopy (SEM), atomic force microscope(AFM), X-ray diffractometer(XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) correspondingly. The experimental results show that the micro-/nano-scale rough structure, together with the long side chain alkyl in HDTMS and the siloxane (Si-O-Si) structure generated after hydrolysis and crosslinking, endows the modified cotton fabric with superhydrophobic properties. In addition, the thermogravimetric analysis shows that the modified sample exhibited excellent thermal stability. Besides, the degradation rates of methylene blue (MB) solution was 90 % when photocatalytic performance was tested on the modified fabric under simulated sunlight, and the contact angle still reached 150°. In addition, the modified fabric showed superior oil-water separation ability, with the separation efficiency higher than 98%, separation flux is greater than 1600 Lm−2 s−1, oil absorption is more than twice its own weight and it has excellent recyclability and reusability, because of its superhydrophobic surface, TiO2-AC/HDTMS fabric also showed superior stain resistance and self-cleaning ability. At the same time, the TiO2-AC/HDTMS treated fabric remained hydrophobic in acid and alkali immersion, 25 home washes, and high strength mechanical properties tests. In short, this simple porous nano-composite material combined with non-fluorosilane coupling agent finishing technology has a broad development prospect in the industrial production of multifunctional advanced textiles.

Advancements in Bioelectricity Generation Through Nanomaterial-Modified Anode Electrodes in Microbial Fuel Cells

The use of nanotechnology in bioelectrochemical systems to recover bioelectricity and metals from waste appears to be a potentially appealing alternative to existing established procedures. This trend exactly characterizes the current renewable energy production technology. Hence, this review focuses on the improvement of the anode electrode by using different functional metal oxide-conducting polymer nanocomposites to enhance microbial fuel cell (MFC) performance. Enhancement of interfacial bioelectrocatalysis between electroactive microorganisms and hierarchical porous nanocomposite materials could enhance cost-effective bioanode materials with superior bioelectrocatalytic activity for MFCs. In this review, improvement in efficiency of MFCs by using iron oxide- and manganese oxide-based polypyrrole hybrid composites as model anode modifiers was discussed. The review also extended to discussing and covering the principles, components, power density, current density, and removal efficiencies of biofuel cell systems. In addition, this research review demonstrates the application of MFCs for renewable energy generation, wastewater treatment, and metal recovery. This is due to having their own unique working principle under mild conditions and using renewable biodegradable organic matter as a direct fuel source.

Meso/microporous MOF@graphene oxide composite aerogels prepared by generic supercritical CO2 technology

The increasing complexity in composition and structure of modern porous nanocomposite materials requires the development of advanced technologies that allow the simultaneous treatment of dissimilar compounds, not only with unlike composition but also involving different classes of pores, e.g., micro and mesopores. This work shows that supercritical CO 2 (scCO 2 ) technology can be used as generic processing aid to obtain composites involving non-reduced graphene oxide (GO) and metal organic frameworks (MOFs) in the form of aerogels with hierarchical porosity. Hybrid aerogels are formed by either depositing ( ex situ ) or growing ( in situ ) MOF nanocrystals onto the surface of 2D GO nanosheets. The archetypal hydrophilic HKUST-1 and UiO-66 and hydrophobic ZIF-8 microporous MOFs are chosen to exemplify the method possibilities. The ex situ route was adequate to prepare hydrophilic MOFs@GO homogeneous composites, while the in situ approach must be used to prepare hydrophobic MOFs@GO aerogels. Moreover, the scCO 2 methodology should be adjusted for each studied MOF in regard of the organic solvent used to disperse the nanoentities constituting the composite. The end-products are obtained in the form of aerogels mimicking the shape of the recipient in which they are contained. The products are characterized in regard of structure by X-ray diffraction, textural properties by low temperature N 2 adsorption/desorption and morphology by electronic microscopy. • scCO 2 as a synthetic platform for fabrication of meso/microporous MOF@GO aerogels. • MOF hydrophobic/hydrophilic nature defines the choice of ex situ/in situ scCO 2 method. • The ex situ route can be applied to a large number of MOFs with hydrophilic nature. • The in situ method can be also applied to hydrophobic MOFs to reduce time/resources. • MOF@GO composites were homogenous with hierarchical micro/meso porosity.

State-of-the-art review of fabrication, application, and mechanical properties of functionally graded porous nanocomposite materials

Abstract Functionally graded porous (FGP) nanocomposites are the most promising materials among the manufacturing and materials sector due to their adjustable physical, mechanical, and operational properties for distinctive engineering applications for maximized efficiency. Therefore, investigating the underlying physical and materialistic phenomena of such materials is vital. This research was conducted to analyze the preparation, fabrication, applications, and elastic properties of functionally graded materials (FGMs). The research investigated for both porous and nonporous synthesis, preparation, and manufacturing methods for ceramics, metallic, and polymeric nanocomposites in the first section, which is followed by deep research of the development of elastic properties of the above-mentioned materials. Main nano-reinforcing agents used in FGMs to improve elastic properties were found to be graphene platelets, carbon nanotubes, and carbon nanofibers. In addition, research studied the impact of nano-reinforcing agent on the elastic properties of the FGMs. Shape, size, composition, and distribution of nano-reinforcing agents were analyzed and classified. Furthermore, the research concentrated on modeling of FGP nanocomposites. Extensive mathematical, numerical, and computational modeling were analyzed and classified for different engineering analysis types including buckling, thermal, vibrational, thermoelasticity, static, and dynamic bending. Finally, manufacturing and design methods regarding different materials were summarized. The most common results found in this study are that the addition of reinforcement units to any type of porous and nonporous nanocomposites significantly increases materialistic and material properties. To extend, compressive and tensile stresses, buckling, vibrational, elastic, acoustical, energy absorption, and stress distribution endurance are considerably enhanced when reinforcing is applied to porous and nonporous nanocomposite assemblies. Ultimately, the review concluded that the parameters such as shape, size, composition, and distribution of the reinforcing units are vital in terms of determining the final mechanical and materialistic properties of nanocomposites.

Multimodal Characterization of Hierarchically Porous Nanocomposite Materials: The Case Study of the PEARL Membrane

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Cultivation of Exoelectrogenic Bacteria in Conductive DNA Nanocomposite Hydrogels Yields a Programmable Biohybrid Materials System.

The use of living microorganisms integrated within electrochemical devices is an expanding field of research, with applications in microbial fuel cells, microbial biosensors or bioreactors. We describe the use of porous nanocomposite materials prepared by DNA polymerization of carbon nanotubes (CNTs) and silica nanoparticles (SiNPs) for the construction of a programmable biohybrid system containing the exoelectrogenic bacterium Shewanella oneidensis. We initially demonstrate the electrical conductivity of the CNT-containing DNA composite by employment of chronopotentiometry, electrochemical impedance spectroscopy, and cyclic voltammetry. Cultivation of Shewanella oneidensis in the conductive materials shows that the exoelectrogenic bacteria populate the matrix of the conductive composite, while nonexoelectrogenic Escherichia coli remain on its surface. Moreover, the ability to use extracellular electron transfer pathways is positively correlated with the number of cells within the conductive synthetic biofilm matrix. The Shewanella-containing composite remains stable for several days and shows electrochemical activity, indicating that the conductive backbone is capable of extracting the metabolic electrons produced by the bacteria under strictly anoxic conditions and conducting them to the anode. Programmability of this biohybrid material system is demonstrated by on-demand release and degradation induced by a short-term enzymatic stimulus. We believe that the application possibilities of such biohybrid materials could even go beyond microbial biosensors, bioreactors, and fuel cell systems.

Multifunctional Graphene-Based Composite Sponge.

Although graphene has been widely used as a nano-filler to enhance the conductivity of porous materials, it is still an unsatisfactory requirement to prepare graphene-based sponge porous materials by simple and low-cost methods to enhance their mechanical properties and make them have good sensing and capacitive properties. Graphene platelets (GnPs) were prepared by the thermal expansion method. Graphene-based sponge porous materials were prepared by a simple method. A flexible sensor was formed and supercapacitors were assembled. Compared with other graphene-based composites, the graphene-based composite sponge has good electrical response under bending and torsion loading. Under 180° bending and torsion loading, the maximum resistance change rate can reach 13.9% and 52.5%, respectively. The linearity under tension is 0.01. The mechanical properties and capacitance properties of the sponge nanocomposites were optimized when the filler fraction was 1.43 wt.%. The tensile strength was 0.236 MPa and capacitance was 21.4 F/g. In cycles, the capacitance retention rate is 94.45%. The experimental results show that the graphene-based sponge porous material can be used as a multifunctional flexible sensor and supercapacitor, and it is a promising and multifunctional porous nanocomposite material.

Nonlocal strain gradient nonlinear primary resonance of micro/nano-beams made of GPL reinforced FG porous nanocomposite materials

The current study deals with the size dependency in the nonlinear primary resonance of harmonic soft excited micro/nano-beams made of functionally graded (FG) porous nanocomposite materials reinforced with graphene platelets (GPLs). The size-dependent mathematical formulations are developed based upon the nonlocal strain gradient theory of elasticity within the framework of a refined hyperbolic shear deformation beam theory. On the basis of the closed-cell Gaussian-Random field scheme as well as the Halpin-Tsai micromechanical modeling, the mechanical properties of the FG porous nanocomposite material reinforced with GPLs are extracted corresponding to the uniform and three different FG patterns of porosity dispersion. The nonlocal strain gradient differential equations of motion including the geometrical nonlinearity are constructed using the variational approach. Thereafter, a numerical solution methodology based on the generalized differential quadrature (GDQ) method together with the Galerkin technique is employed to obtain the nonlocal strain gradient frequency-response and amplitude-response associated with the nonlinear primary resonance of the FG porous nanocomposite micro/nano-beams reinforced with GPLs. It is found that the nonlocal size effect makes a reduction in the excitation amplitude associated with the both bifurcation points, especially for the first bifurcation point. However, the strain gradient size dependency causes to increase them. Also, it is displayed that by increasing the value of the porosity coefficient, the peak of the jump phenomenon associated with the soft harmonic excited FG porous nanocomposite micro/nano-beam is shifted to higher excitation frequency, which makes an enhancement in the hardening behavior related to the nonlinear primary resonance. Communicated by Eleonora Tubaldi

Preparation of chitosan/SiO2-loaded graphene composite beads for efficient removal of bilirubin

Porous nanocomposite materials possess enhanced adsorption properties, but uniformly dispersing nanofillers in polymer matrices is still a challenging technical difficulty. In this study, modification through loading with SiO2 successfully improved the dispersibility of graphene in chitosan suspensions. By employing a phase-inversion method, cross-linked chitosan/SiO2-loaded graphene (CS/graphene-SiO2) composite beads were prepared. The resulting CS/graphene-SiO2 beads were characterized by scanning electron microscopy and Raman spectroscopy, which clearly showed that graphene was well-dispersed in the chitosan matrix. Adsorption results demonstrated that CS/graphene-SiO2 beads possessed much better adsorption capacity for bilirubin (77.87%) compared to pure chitosan (CS) beads (22.47%), mainly due to the synergistic effect between the hydrophobic forces of graphene and the electrostatic interactions provided by the amino groups of CS. The adsorption of bilirubin was found to match a monolayer model, as well as a pseudo-first-order kinetic model. The mechanical strength of composite beads was significantly improved as compared to CS beads, due to the incorporation of graphene. The effects on hemolytic activity and the components of blood were negligible, which indicate an excellent compatibility of the obtained composite beads with blood. Overall, the proposed CS/graphene-SiO2 beads as an efficient adsorbent for bilirubin have high potential in blood purification applications.

An Innovative Porous Nanocomposite Material for the Removal of Phenolic Compounds from Aqueous Solutions.

Energy efficient, low-cost, user-friendly, and green methods for the removal of toxic phenolic compounds from aqueous solution are necessary for waste treatment in industrial applications. Herein we present an interesting approach for the utilization of oxidized carbon nanotubes (CNTs) in the removal of phenolic compounds from aqueous solution. Dried pristine CNTs were stably incorporated in a solid porous support of polydimethylsiloxane (PDMS) facilitating the handling during both oxidation process of the nanomaterial and uptake of phenolic compounds, and enabling their safe disposal, avoiding expensive post-treatment processes. The adsorption studies indicated that the materials can efficiently remove phenolic compounds from water with different affinities towards different phenolic compounds. Furthermore, the adsorption kinetics and isotherms were studied in detail. The experimental data of adsorption fitted well with Langmuir and Freundlich isotherms, and pseudo-second-order kinetics, and the results indicated that the adsorption process was controlled by a two-step intraparticle diffusion model. The incorporation of CNTs in polymeric matrices did not affect their functionality in phenol uptake. The material was also successfully used for the removal of phenolic compounds from agricultural waste, suggesting its possible application in the treatment of wastewater. Moreover, the surface of the material could be regenerated, decreasing treatment costs.

Regenerable, innovative porous silicon-based polymer-derived ceramics for removal of methylene blue and rhodamine B from textile and environmental waters.

The presence of residual color in treated textile wastewater above the regulation limits is still a critical issue in many textile districts. Innovative, polymer-derived ceramics of the Si-C-O system were here synthesized in order to obtain porous nanocomposite materials where a free carbon phase is dispersed into a silicon carbide/silicon oxycarbide network. The sorbents were comprehensively characterized for the removal of two model water-soluble dyes (i.e., the cation methylene blue and the zwitterion rhodamine B). Adsorption is very rapid and controlled by intra-particle and/or film diffusion, depending on dye concentration. Among the nanocomposites studied, the SiOC aerogel (total capacity about 45mg/g, is easily regenerated under mild treatment (250°C, 2h). Adsorption of dyes is not affected by the matrix composition: removals of 150mg/L methylene blue from river water and simulated textile wastewater with high content of metal ions (2-50mg/L) and chemical oxygen demand (800mg/L) were higher than 92% and quantitative for a dye concentration of 1mg/L.

Nanocomposite Foam Involving Boron Nitride Nanoplatelets and Polycaprolactone: Porous Structures with Multiple Length Scales for Oil Spill Cleanup

Herein, we report a facile approach to fabricate highly porous nanocomposites made from polycaprolactone (PCL) and boron nitride (BN) nanoplatelets using coprecipitation mixing and supercritical CO2 drying. The presence of boron nitride nanoplatelets in polycaprolactone matrix enhanced the porosity of polycaprolactone foams and also improved the interfacial compatibility with oils and nonpolar organic solvents. Through a synergistic combination of surface morphology and interfacial tension effect, PCL:BNNP foams achieved a high hydrophobicity with a contact angle of 135° while being strongly oleophilic with a near zero contact angle for oils and nonpolar organic solvents. The absorption capacity was 6.1, 5.8, 4.3, 3.7, and 3.4 for paraffin oil, silicone oil, corn oil, hexadecane, and n-hexane, respectively. Additionally, the nanocomposite foam also demonstrated promising reusability and oil stability. Overall, this study offers a novel and facile strategy for fabricating porous nanocomposite materials wit...

Experimentally-based multiscale model of the elastic moduli of bovine trabecular bone and its constituents.

The elastic moduli of trabecular bone were modeled using an analytical multiscale approach. Trabecular bone was represented as a porous nanocomposite material with a hierarchical structure spanning from the collagen-mineral level to the trabecular architecture level. In parallel, compression testing was done on bovine femoral trabecular bone samples in two anatomical directions, parallel to the femoral neck axis and perpendicular to it, and the measured elastic moduli were compared with the corresponding theoretical results. To gain insights on the interaction of collagen and minerals at the nanoscale, bone samples were deproteinized or demineralized. After such processing, the treated samples remained as self-standing structures and were tested in compression. Micro-computed tomography was used to characterize the hierarchical structure of these three bone types and to quantify the amount of bone porosity. The obtained experimental data served as inputs to the multiscale model and guided us to represent bone as an interpenetrating composite material. Good agreement was found between the theory and experiments for the elastic moduli of the untreated, deproteinized, and demineralized trabecular bone.

Carbon Nanotube–Chitosan Composite Beads with Radially Aligned Channels and Nanotube‐Exposed Walls for Bilirubin Adsorption

Porous nanocomposite materials combine the advantages of a polymer matrix in forming a stable framework and the nanofillers that provide high surface area. Here, we use carbon nanotubes (CNTs) as nanofillers to fabricate chitosan beads with controlled porous structure. We synthesized spherical chitosan–CNT composite beads via freeze casting by dropping a mixed solution into liquid nitrogen, and the resulting highly porous composite beads contain radially oriented channels with hybrid chitosan–CNT channel walls. In particular, we observed localized regions of small CNT agglomerates embedded within the chitosan matrix at a lower CNT loading (40 wt%), and predominately exposed CNTs distributed throughout the channel walls at a higher loading (80 wt%). Owing to the hierarchical open‐porous structure and mesopores provided by exposed CNTs, these composite beads showed much higher adsorption capacity (43.6 mg g−1 within 2 h) to bilirubin than CNT‐free chitosan beads. Our nanocomposite beads with tunable pore wall structure have potential applications in environmental and biomedical areas such as efficient adsorption materials.

Layer by layer assembly synthesis of Fe3O4@MOFs/GO core–shell nanoparticles

Magnetic core–shell spheres Fe3O4@MOFs and Fe3O4@MOFs/GO were prepared using layer by layer assembly method. Fe3O4@MOFs and Fe3O4@MOFs/GO were characterized by XRD, FTIR, SEM, TEM and VSM. The results showed that both magnetic spheres were with core–shell structure. The method was proved to be valuable for producing core–shell structure with porous nanocomposite materials as shell. Methylene blue was selected as drug model to study the drug loading of the synthesized spheres. It was found that the addition of graphene oxide (GO) enhanced the drug loading amount of magnetic sphere.

Macroporous Nanocomposite Materials Prepared by Solvent Evaporation from Pickering Emulsion Templates

Hydroxyapatite (HAp)/poly(L‐lactic acid) (PLLA) interconnected macroporous materials are facilely and effectively fabricated by templating water‐in‐dichloromethane with PLLA (W/O) Pickering emulsions. The HAp nanoparticles modified with PLLA (g‐HAp nanoparticles) are used as effective particulate emulsifiers to produce stable W/O Pickering emulsions. Evaporation of the W/O Pickering emulsions directly leads to interconnected porous nanocomposite materials in absence of any chemical reactions. This simple and effective method can be used to prepare a variety of functionalized porous materials, which are suitable for biomedical applications.

Synthesis of porous MgO-biochar nanocomposites for removal of phosphate and nitrate from aqueous solutions

A new synthesis was developed to create highly porous nanocomposite material consisting of MgO nano-flakes within a biochar matrix that has high sorption ability for ionic contaminations. The synthesis method was used in laboratory to produce MgO-biochar nanocomposites from a variety of carbon-rich biomass. Physical and chemical properties of the synthesized nanocomposites were studied systematically with X-ray powder diffraction, thermogravimetric analysis, scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis. In addition, batch sorption experiment was conducted to determine the sorption ability of the MgO-biochar nanocomposites to aqueous phosphate and nitrate. The results showed that the MgO nano-flakes have uniform morphologies and disperse uniformly on the surface of the biochar matrix. HR-TEM indicated that the biochar matrix is mesoporous with average pore size of 50nm and the MgO nano-flakes have spacing between 2 and 4nm, which can serve as adsorption sites for anions. As a result, all the tested MgO-biochar nanocomposites showed excellent removal efficiencies to phosphate and nitrate in water. Nanocomposites made from sugar beet tailings and peanut shells had the best performances with Langmuir adsorption capacities as high as 835mgg−1 for phosphate and 95mgg−1 for nitrate, respectively, much higher than the reported values of other adsorbents.

Carbon Nanofibers “Spot‐Welded” to Carbon Felt: A Mechanically Stable, Bulk Mimic of Lotus Leaves

Graphitic carbon nanofibers are catalytically grown on commercial carbon felt microfibers, and carbothermal treatment then produces interfacial silicon carbide phase rendering the supported nanofibers mechanically robust and chemically stable. This pliable 3-dimensional porous nanocomposite material reveals a hierarchical structure mimicking lotus leaves and depicts superhydrophobicity and reversible wettability.