Preparation Of Hybrid Materials Research Articles

Highly Cytocompatible Polylactic Acid Based Electrospun Microfibers Loaded with Silver Nanoparticles Generated onto Chestnut Shell Lignin for Targeted Antibacterial Activity and Antioxidant Action.

Electrospun (e-spun) fibers are generally regarded as powerful tools for cell growth in tissue regeneration applications, and the possibility of imparting functional properties to these materials represents an increasingly pursued goal. We report herein the preparation of hybrid materials in which an e-spun d,l-polylactic acid matrix, to which chitosan or crystalline nanocellulose was added to improve hydrophilicity, was loaded with different amounts of silver(0) nanoparticles (AgNP) generated onto chestnut shell lignin (CSL) (AgNP@CSL). A solvent-free mechanochemical method was used for efficient (85% of the theoretical value by XRD analysis) Ag(0) production from the reduction of AgNO3 by lignin. For comparison, e-spun fibers containing CSL alone were also prepared. SEM and TEM analyses confirmed the presence of AgNP@CSL (average size 30 nm) on the fibers. Different chemical assays indicated that the AgNP@CSL containing fibers exhibited marked antioxidant properties (EC50 1.6 ± 0.1 mg/mL, DPPH assay), although they were halved with respect to those of the CSL containing fibers, as expected because of the efficient silver ion reduction. All the fibers showed high cytocompatibility toward human mesenchymal stem cells (hMSCs) representative of the self-healing process, and their antibacterial properties were tested against the pathogens Escherichia coli (E. coli), Staphylococcus epidermidis, and Pseudomonas aeruginosa. Finally, competitive surface colonization as simulated by cocultures of hMSC and E. coli showed that AgNP@CSL loaded fibers offered the cells a targeted protection from infection, thus well balancing cytocompatibility and antibacterial properties.

Synthesis of hybrid materials containing H-ZSM-5 and CeO2 for green butadiene production

Synthesis of hybrid materials combining two or more components with different properties is a commonly used strategy to obtain high-performance materials for a wide range of different applications, including catalytic reactions with a complex reaction network. In this work, two synthesis approaches are investigated to prepare hybrid materials containing two well-defined phases, i.e. H-ZSM-5 and CeO2. By dispersing nano-sized H-ZSM-5 on CeO2, and by synthesizing a core-shell catalyst with a nano H-ZSM-5 core and a ceria shell, a high intimacy between H-ZSM-5 and CeO2 was obtained, while keeping the characteristic properties of each phase. The dehydration of 1,3-butanediol is used as a test reaction to explore the potential of these materials. A ratio between the selectivities of the desired product and intermediates, i.e. 1,3-butadiene (BD), 3-buten-2-ol (3B2OL), and 2-buten-1-ol (2B1OL) to the undesired product propylene (PP) was defined: (BD+3B2OL+2B1OL)/PP. Dispersing H-ZSM-5 zeolites on a CeO2 surface was the optimal synthesis route to enhance the 1,3-butadiene selectivity, and a (BD+3B2OL+2B1OL)/PP selectivity ratio was obtained (3.9) compared to its parent material (2.1).

Improving Oxidative Catalytic Efficiency for Fuels Desulfurization Using Hybrid Materials Based in MOF‐808@SBA‐15

This work unveils a route for a new generation of heterogeneous polyoxometalate (POMs) based catalysts associated to the preparation of hybrid materials as a triad of POMs, mesoporous silica (SBA‐15) and microporous MOF structures (MOF‐808). The prepared catalyst, PMo12@MOF‐808@SBA‐15, with the main active center the phosphomolybdic acid (PMo12), was successfully applied for the desulfurization of a multicomponent fuel. Its oxidative catalytic performance showed to be considerable superior to the isolated POM@MOF and able to be recycled for more catalytic cycles without active loss. The higher catalytic performance seems to be directly related with the preparation of a more amorphous MOF structure within the channels of SBA‐15, in the presence of active POM guests.

Organic-inorganic covalent-ionic molecules for elastic ceramic plastic.

Although organic-inorganic hybrid materials have played indispensable roles as mechanical1-4, optical5,6, electronic7,8 and biomedical materials9-11, isolated organic-inorganic hybrid molecules (at present limited to covalent compounds12,13) are seldom used to prepare hybrid materials, owing to the distinct behaviours of organic covalent bonds14 and inorganic ionic bonds15 in molecular construction. Here we integrate typical covalent and ionic bonds within one molecule to create an organic-inorganic hybrid molecule, which can be used for bottom-up syntheses of hybrid materials. A combination of the organic covalent thioctic acid (TA) and the inorganic ionic calcium carbonate oligomer (CCO) through an acid-base reaction provides a TA-CCO hybrid molecule with therepresentative molecular formula TA2Ca(CaCO3)2. Its dual reactivity involving copolymerization of the organic TA segment and inorganic CCO segment generates the respective covalent and ionic networks. The two networks are interconnected through TA-CCO complexes to form a covalent-ionic bicontinuous structure within the resulting hybrid material, poly(TA-CCO), which unifies paradoxical mechanical properties. The reversible binding of Ca2+-CO32- bonds in the ionic network and S-S bonds in the covalent network ensures material reprocessability with plastic-like mouldability while preserving thermal stability. The coexistence of ceramic-like, rubber-like and plastic-like behaviours within poly(TA-CCO) goes beyond current classifications of materials to generate an 'elastic ceramic plastic'. The bottom-up creation of organic-inorganic hybrid molecules provides a feasible pathway for the molecular engineering of hybrid materials, thereby supplementing the classical methodology used for the manufacture of organic-inorganic hybrid materials.

Lysozyme–Mineral Clay Systems: Comparison of Interaction for Controlled Release in Feed Application

A synthetic approach to bond lysozyme (LY) to commercial natural carriers, namely clay minerals (bentonite, BN; and sepiolite, SP) and commercial zeolite (Phil 75®, PH), already in use in feed formulation, is proposed. The synthetic route, which implies solid–liquid adsorption, is a simple and effective way for preparing hybrid materials characterized by LY loadings up to 37 mgLY/gcarrier. By operating at pH 4.3, initial LY content of 37.5 mgLY/gcarrier, and reaction time of 90 min, hybrid materials with LY loadings of 37, 35, and 12 mgLY/gcarrier for LY-SP, LY-BN, and LY-PH, respectively were obtained. The LY initial concentration and pH, as well as the physico-chemical properties of the carries were found to be the parameters that govern the synthesis of the materials. The driving force for an effective LY adsorption and interaction is the combined Zero Point Charge (ZPC) of the carriers, always negative (in the range between −4 and −170 mV) and the positive ZPC of LY, as well as the carrier morphology, characterized by mesoporosity (pore dimensions in the range of 5–12 nm). However, it is the interaction of charges of opposite sign that mainly affects LY loadings and bond strength. Based on SEM-EDX analysis, LY molecules are quite homogeneously spread onto the carriers’ surface. TG-DTG analyses showed that the LY–carrier interaction in the hybrid materials is stronger than that in a simple mechanical mixture of the components. Specifically, in the hybrid materials, the phenomenon at 300 °C, associated to LY decomposition, is broadened and slightly shifted towards higher temperatures (320–350 °C), whereas in a mechanical mixture of the same composition, it occurs at temperatures closer to those of free LY, as if there were no or very weak interactions. At pH 3, a very little LY release, 0.03 and 0.01 mgLY/gcarrier, was found for LY-BN and LY-PH, respectively. The latter became larger at pH 7, 0.06 mgLY/gcarrier for both BN and PH carriers, suggesting that BN and PH are better modulators of LY release. The paper provides insights for the study and the development of new optimized feed formulations for the targeted delivery of natural compounds with antimicrobial activity, alternatives to antibiotics, and vaccinal antigens.

Synthesis of cuprous oxide/silver (Cu2O/Ag) hybrid as surface-enhanced Raman scattering probe for trace determination of methyl orange.

Recently, there have been publications on preparing hybrid materials between noble metal and semiconductor for applications in surface-enhanced Raman scattering (SERS) substrates to detect some toxic organic dyes. However, the use of cuprous oxide/silver (Cu2O/Ag) to measure the trace amounts of methyl orange (MO) has not been reported. Therefore, in this study, the trace level of MO in water solvent was determined using a SERS substrate based on Cu2O microcubes combined with silver nanoparticles (Ag NPs). Herein, a series of Cu2O/Agx ( 1-5) hybrids with various Ag amounts was synthesized via a solvothermal method followed by a reduction process, and their SERS performance was studied in detail. X-ray diffraction (XRD) and scanning electron microscopy results confirmed that 10 nm Ag NPs were well dispersed on 200-500 nm Cu2O microcubes to form Cu2O/Ag heterojunctions. Using the as-prepared Cu2O and Cu2O/Agx as MO probe, the Cu2O/Ag5 nanocomposite showed the highest SERS activity of all samples with the limit of detection as low to 1 nM and the enhancement factor as high as 4 × 108. The logarithm of the SERS peak intensity at 1389 cm-1 increased linearly with the logarithm of the concentration of MO in the range from 1 nM to 0.1 mM.

MoS2 nanoflower-decorated lignin nanoparticles for superior lubricant properties.

Lignin has been, for a long time, treated as a low-value waste product. To change this scenario, high-value applications have been recently pursued, e.g., the preparation of hybrid materials with inorganic components. Although hybrid inorganic-based materials can benefit from the reactive lignin phenolic groups at the interface, often responsible for optimizing specific properties, this is still an underexplored field. Here, we present a novel and green material based on the combination of hydroxymethylated lignin nanoparticles (HLNPs) with molybdenum disulfide (MoS2) nanoflowers grown via a hydrothermal route. By bringing together the lubricant performance of MoS2 and the structural stability of biomass-based nanoparticles, a MoS2-HLNPs hybrid is presented as a bio-derived additive for superior tribological performances. While FT-IR analysis confirmed the structural stability of lignin after the hydrothermal growth of MoS2, TEM and SEM micrographs revealed a homogeneous distribution of MoS2 nanoflowers (average size of 400 nm) on the HLNPs (average size of 100 nm). Regarding the tribological tests, considering a pure oil as reference, only HLNPs as bio-derived additives led to a reduction in the wear volume of 18%. However, the hybrid of MoS2-HLNPs led to a considerably higher reduction (71%), pointing out its superior performance. These results open a new window of opportunity for a versatile and yet underexplored field that can pave the way for a new class of biobased lubricants.

Synthesis and Characterization of Hybrid Materials Derived from Conjugated Copolymers and Reduced Graphene Oxide.

In this study the preparation of hybrid materials based on reduced graphene oxide (rGO) and conjugated copolymers is reported. By tuning the number and arrangement of thiophenes in the main chain (indacenothiophene or indacenothienothiophene) and the nature of the polymer acceptor (difluoro benzothiadiazole or diketopyrrolopyrrole) semiconducting copolymers were synthesized through Stille aromatic coupling and characterized to determine their molecular characteristics. The graphene oxide was synthesized using the Staudenmaier method and was further modified to reduced graphene oxide prior to structural characterization. Various mixtures with different rGO quantities and conjugated copolymers were prepared to determine the optoelectronic, thermal and morphological properties. An increase in the maximum absorbance ranging from 3 to 6 nm for all hybrid materials irrespective of the rGO concentration, when compared to the pristine conjugated copolymers, was estimated through the UV-Vis spectroscopy indicating a differentiation on the optical properties. Through voltammetric experiments the oxidation and reduction potentials were determined and the calculated HOMO and LUMO levels revealed a decrease on the electrochemical energy gap for low rGO concentrations. The study indicates the potential of the hybrid materials consisting of graphene oxide and high band gap conjugated copolymers for applications related to organic solar cells.

Working electrode geometry effect: A new concept for fabrication of patterned polymer brushes via SI-seATRP at ambient conditions

First reports concerning the use of atom transfer radical polymerization (ATRP) to prepare patterned hybrid materials appeared more than 20 years ago. However, the development of new methods of preparation of patterned materials is still at the forefront of scientific interest. In this paper, we describe surface-initiated simplified electrochemically mediated ATRP (SI- se ATRP) under constant current conditions, used for the fabrication of patterned polymer brushes under ambient conditions at the microliter scale. It is shown that appropriate selection of surface and shape of the working electrode (WE) allows handling the polymerization of (meth)acrylates, acrylates and acrylamides directly on the laboratory bench. The complete procedure includes a minimum amount of reagents and an optimal amount of a catalytic complex equal to 300 ppm. The use of a platinum wire mesh electrode guarantees obtaining polymers forming unique patterns. The observed patterning phenomenon could be explained by the mechanism of electrochemically mediated ATRP ( e ATRP) and is directly related to the working electrode geometry, and diffusion of the catalyst Cu I Br/TPMA (where TPMA: tris(2-pyridylmethyl)amine). • Diffusion-controlled polymerization for the preparation of hybrid materials. • Patterned polymer brushes fabricated via SI- se ATRP at ambient conditions. • Two-electrode system applied under constant current conditions for μL-scale ATRP. • Dual activator (re)generation during SI- se ATRP of DMAEMA in (in)organic medium. • XPS and EDS analysis of patterned polymer brushes.

Effects of Incorporating Titanium Dioxide with Titanium Carbide on Hybrid Materials Reinforced with Polyaniline: Synthesis, Characterization, Electrochemical and Supercapacitive Properties

We report on the synthesis of titanium dioxide by titanium carbide for the preparation of hybrid material reinforced with polyaniline (PANI@TiO2–TiC) using the in situ polymerization technique. The effectiveness of the samples on the thermal, optical and electrochemical properties was investigated. The XRD, XPS, FTIR, SEM and TEM results confirm the successful synthesis of the PANI, PANI@TiC and PANI@TiO2–TiC samples. Through this, a good connection, an excellent relationship between the structures and the properties of the synthesized hybrid materials were obtained. Moreover, the electrical conductivity and optical bandgap were also tested. Remarkably good electrochemical characteristics were identified by cyclic voltammetry. Moreover, the galvanostatic charge–discharge (GCD) of the supercapacitor was remarkably high. Cyclic stability showed good retention after 1500 cycles at 1.5 A·g−1.

Synergistic effects of COF and GO on high flux oil/water separation performance of superhydrophobic composites

Covalent organic frameworks (COFs) have been emerged as potential coating material because of their rigid porous structure and excellent chemical stability, however, the challenges of complicated preparation process and poor processability are still remained. As a widely used composite matrix, graphene oxide usually suffers from swells and poor acid/base resistance caused by the weakening of π-π interaction between graphene sheets with large interlayer spacing in an aqueous environment. Currently, it is a trend to combine COFs and graphene oxide to utilize their synergistic effect in materials. In this study, a simple one-step method is developed to prepare hybrid materials based on COFs and GO without using any special device generally required for COFs fabrication. Significantly, synergistic effects of COFs and GO which can improve the acid /alkali resistance of GO in water as well as overcome the COFs’ tendency to agglomeration further make the hybrid materials stable in separation process. The hybrid materials formed by COFs polymerization and parallel covalent linking to GO were translated into recyclable superhydrophobic composite coating by spraying onto filter paper. The fabricated coatings presented ultra-high oil/water permeation flux of 26,000 L m-2h−1 bar−1 with > 98% separation efficiency. Moreover, the coating exhibited exceptional chemical stability in acid and basic environment with excellent cycling stability. The simple methodology presented here will be expected to open up a new route for the fabrication of COFs based hybrid materials for wide range of applications.

Functionalized Corroles for Sensor Applications

Corrole continues to attract the interest of different research groups, since this macrocycle shows peculiar and intriguing characteristics, which open its application in different fields.In the last few years, we have been interested to exploit corrole derivatives as receptors in chemical sensors, because the peculiar coordination chemistry of this contracted macrocycle can allow the preparation of optimized cross sensitive sensor arrays.For this reason, the functionalization of the corrole is a fundamental step for the optimization of the macrocycle features for the target application.We have been interested in the introduction at the peripheral positions of the corrole ring of different substituents, because they can allow the preparation of hybrid materials. These hybrid materials have been successfully exploited to develop chemical sensors.The characterization of these species, together the applications of the functionalized corroles will be presented and discussed.

A comparative study on surfactant cetyltrimethylammoniumbromide modified clay‐based poly(p‐anisidine) nanocomposites: Synthesis, characterization, optical and electrochemical properties

AbstractThe preparation of hybrid materials, namely poly(p‐anisidine)@Clay (poly(pAnis)@Clay) and poly(p‐anisidine)@cetyltrimethylammoniumbromide‐Clay (poly(pAnis)@CTAB‐Clay), prepared by oxidative polymerization process is presented. The formation of nanomaterials has been confirmed by XRF, XPS, FT‐IR, and UV–Vis spectroscopy. Interestingly, the study of the optical band gap energy (Eg) evince lowest value of 3.22 eV for poly(pAnis)@CTAB‐Clay compared to poly(pAnis)@Clay with 3.26 eV. XRD results demonstrate that the intercalation of the poly(pAnis) into the Clay was confirmed by the increased interlayer spacing, the exfoliation and intercalation forms were affirmed in the TEM images. In addition, the electrochemical behavior indicates that the prepared nanocomposites are electroactive. These results are heartening in respect with the objective to utilize them in the field of technology and research related to the photovoltaics application.

A green approach for hybrid material preparation based on carbon nanotubes/lignosulfonate decorated with silver nanostructures for electrocatalytic sensing of H2O2

We present a green and simple approach for the fabrication of multi-walled carbon nanotubes decorated with silver nanoparticles (MWCNT/LS/NAg) via lignosulfonate assisted synthesis. Due to reducing and stabilizing properties of lignosulfonate, silver nanoparticles were produced in a facile synthetic route without the addition of any reductant or toxic solvents. The existence of silver nanoparticles was confirmed through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was employed to investigate the morphologies and structures of prepared functional nanomaterials. Cyclic voltammograms of the MWCNT/LS/NAg nanomaterial presented, revealed well-defined and sharp redox peaks recorded in phosphate buffer (pH = 7.4) corresponding to silver nanoparticles electroactivity. The obtained data proved that the hybrid material exhibits persistent reversible redox behavior. The hybrid nanomaterial possesses strong electrocatalytic properties toward hydrogen peroxide reduction. Based on the electrocatalytic properties of the material, the amperometric detection of H2O2 at −0.2 V demonstrated a wide linear range of 6.00–486 μM. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.169 μM and 3.543 μM, respectively. Substantial electrochemical performance shows the proposed material as a promising electrochemical sensing platform for the detection of hydrogen peroxide.

Phosphorus-Containing Silsesquioxane Derivatives as Additive or Reactive Components of Epoxy Resins.

Two phosphorus-containing cage-like silsesquioxane derivatives were synthesized as reactive or additive flame retardants for epoxy resin. The silsesquioxanes were obtained via an epoxide ring-opening reaction using a 10-hydroxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPA). In one derivative containing in its structure 4 glycidoxypropyl and 4 phosphate groups, denoted as 4P4GS, only half of the epoxy rings was reacted with phosphate to obtain a reactive additive, while in the second derivative containing 8 phosphate groups, denoted as 8PS, all epoxy groups were converted, thus an additive modifier was obtained. The silsesquioxanes containing phosphorus atoms and the reactive phosphorus-free silsesquioxane derivative (octakis[(3-glycidoxypropyl)dimethylsiloxy]octasilsesquioxane (8GS)) were used to prepare hybrid materials based on epoxy resin. To compare the impact of the structure of silsesquioxane derivatives on the properties of hybrid materials, a number of samples containing 1, 5, and 10% of the modifiers making a series of epoxy materials containing additive or reactive modifiers, were obtained. The modified epoxies were studied using scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), nanoindentation, water contact angle, and cone calorimetry tests to assess the effects of the modifier structure on the physicochemical properties of the investigated materials.

Hybrid Spintronic Materials from Conducting Polymers with Molecular Quantum Bits

AbstractHybrid materials consisting of organic semiconductors and molecular quantum bits promise to provide a novel platform for quantum spintronic applications. However, investigations of such materials, elucidating both the electrical and quantum dynamical properties of the same material have never been reported. Here the preparation of hybrid materials consisting of conducting polymers and molecular quantum bits is reported. Organic field‐effect transistor measurements demonstrate that the favorable electrical properties are preserved in the presence of the qubits. Chemical doping introduces charge carriers into the material, and variable‐temperature charge transport measurements reveal the existence of mobile charge carriers at temperatures as low as 15 K. Importantly, quantum coherence of the qubit is shown to be preserved up to temperatures of at least 30 K, that is, in the presence of mobile charge carriers. These results pave the way for employing such hybrid materials in novel molecular quantum spintronic architectures.

Carbon nanotube arrays hybrid membrane with excellent separation performance and conductivity

Hybrid materials based on carbon nanotubes (CNTs) and polymers have shown attractive properties and potential applications. However, the poor quality and aggregation of CNTs are challenging during the preparation of hybrid materials. To address these issues, we fabricated the vertically aligned (VA) CNT (open-end) hybrid membrane with annealing treatment, which significantly improves the phenol separation performance, single gas permeability of CO2 and N2, and binary CO2/N2 mixture separation performance. The free volume provided by the orderly CNT channels and their atomically smooth walls contribute to the markedly increased diffusion rate and permeability of the membrane. The density functional theory (DFT) calculations indicate that the small molecules in the membrane preferentially transport along the internal channels of CNTs. Furthermore, this membrane also has excellent conductivity and resistance stability after 50 cycles of tensile deformation. For the first time, it reveals that this unique structured CNTs membrane can be applied in environmental, gas separation, and electronics fields with superior performance.

Tailoring the droplet size of Pickering emulsions by PISA synthesized polymeric nanoparticles

Pickering emulsions, water or oil droplets stabilized solely by solid particles, are attracting increasing attention, due to the fascinating possibilities for applications in food, pharmaceuticals and preparation of hybrid materials. In this paper, we report oil-in-water (O/W) Pickering emulsions stabilized solely by polymerization-induced self-assembly (PISA) synthesized diblock copolymer spherical nanoparticles. Poly (N,N-dimethylaminoethyl methacrylate)-b-poly (benzyl methacrylate) (PDMA-b-PBzMA) diblock copolymer nanoparticles with 20 wt% solid content were prepared in ethanol via RAFT dispersion polymerization. Then PDMA-b-PBzMA nanoparticles were used as emulsifiers to prepare O/W Pickering emulsions by homogenization. The regulation of droplet size of the O/W Pickering emulsion was systemically investigated by adjusting the size of emulsifiers, the concentration of emulsifiers, and the ratio of oil/water. Moreover, Pickering emulsion polymerization was successfully applied to prepare poly (laurate methacrylate) microparticles. These results provide instructive insights to choose proper nanoparticles for the preparation of Pickering emulsions and control over the size of emulsion droplets.

Preparing Pd catalysts based on urea ligand via electrospinning for Suzuki–Miyaura cross‐coupling reactions

Pd‐catalyzed Suzuki–Miyaura cross‐coupling (SMC) reactions are important in chemistry. In this work, using electrospinning technology, we prepared a novel type of composite catalyst with ligand structures such as urea‐Pd/PAN (polyacrylonitrile) and used them to catalyze SMC reactions in nontoxic systems and “green” conditions (air atmosphere, low temperature, and short reaction time). This method of preparing hybrid materials is simple and easy to operate. The higher catalytic activity of the catalysts is attributed to active centers with rich electrons transferred from ligands with unique structures, which can decrease the activation energy of the rate‐determining step (oxidative addition). In addition, urea‐Pd/PAN composite catalysts exhibit higher catalytic performance than those reduced by H2 because of the smaller size of active species and the more‐efficient oxidative addition to Pd0–ligand complexes compared to Pd0.

Acroleylcorroles

Corrole continues to attract the interest of different research groups, since this macrocycle shows peculiar and intriguing characteristics, which open its application in different fields.For this reason, the functionalization of the corrole is a fundamental step for the optimization of the macrocycle features for the target application.We have been interested in the introduction at the peripheral positions of the corrole ring of acroleyl groups by Vilsmeier reaction, because they can allow the preparation of hybrid materials by grafting the corrole derivative onto poly-acrolein microballs. These hybrid materials have been successfully exploited to develop chemical sensors.The regioselectivity of the Vilsmeier reaction strongly depends on the corrole structure and in the case of the free base the macrocyclic inner core showed an unexpected reactivity.The characterization of these species, together the applications of the functionalized corroles will be presented and discussed.