Organic-inorganic Nanocomposites Research Articles

Biomacromolecules within bivalve shells: Is chitin abundant?

Bivalve shells are inorganic-organic nanocomposites whose material properties outperform their purely inorganic mineral counterparts. Most typically the inorganic phase is a polymorph of CaCO3, while the organic phase contains biopolymers which have been presumed to be chitin and/or proteins. Identifying the biopolymer phase is therefore a crucial step in improving our understanding of design principles relevant to biominerals. In this work we study seven shells; four are examples of nacroprismatic shells (Alathyria jacksoni, Pinctada maxima, Hyriopsis cumingii and Cucumerunio novaehollandiae), one homogeneous (Arctica islandica), and two are crossed lamellar (Callista kingii, Tridacna gigas). Both intact shells, their organic extracts as isolated after decalcification in acid, and the periostracum overlay have been studied by solid-state CP-MAS NMR, FTIR, SEM and chemical analysis. In none of the shells examined in this work do we find a significant contribution to the organic fraction from chitin or its derivatives despite popular models of bivalve biomineralization which assume abundant chitin in the organic fraction of mollusk bivalve shells. In each of the nacroprismatic extracts the 13C NMR spectra represent similar proteinaceous material, Ala and Gly-rich and primarily organized as β-sheets. A different, yet highly conserved protein was found in the periostracum covering each of the three nacreous shells studied. The Arctica islandica shells with homogeneous microstructure contained proteins which do not appear to be silk-like, while in the crossed lamellar shells we extracted too little organic matter to characterize. Statement of SignificanceHydrophobic macromolecules are structural components within the calcareous inorganic matrix of bivalve shells and are responsible for enhanced materials properties of the biominerals. Prevalent models suggest that chitin is such major hydrophobic component. Contrary to that we show that chitin is rare within the hydrophobic biopolymers which primarily consist of proteinaceous matter with structural motifs as silk-like β-sheets, or others yet to be determined. Recognizing that diverse proteinaceous motifs, devoid of abundant chitin, can yield the optimized mechanical properties of bivalve shells is critical both to understand the mechanistic pathways by which they regulate biomineralization and for the design of novel bioinspired materials.

Synthesis and characterization of hybrid organic–inorganic nanocomposite for photocatalytic application

We report a simple precipitation method for the synthesis of organic–inorganic hybrid composite Alq3–WO3 materials. The incorporation of WO3 into Alq3 samples was demonstrated using different techniques. The surface morphology signifies the aggregation in the particles. Conversely, the decrease in the photoluminescence, band gap, prolonged excited-state lifetimes, and the higher conductivity in the impedance measurements suggest a much lower recombination rate in the final composite. Overall, the present finding demonstrates an enhanced separation and transfer efficiency of the photo-generated charge carriers upon combing WO3 semiconductor with Alq3 organic complex. The photocatalytic degradation property of Alq3–WO3 composite has been studied using methylene blue (MB) as a model organic pollutant. The Alq3–WO3 composite analysis possesses good catalytic activities. From the photocatalytic degradation experiment, it is found that the data fit well with the pseudo-first-order equation for the whole range of irradiation time with a high correlation coefficient.

Fabrication and microwave absorption properties of size-controlled polymer/Fe3O4hybrid microsphere based on aggregation-induced emission active polyarylene ether nitrile

The article fabricated novel polymer/magnetic hybrid microspheres via solvothermal method by using ferroferric oxide (Fe3O4) and aggregation-induced emission (AIE) active polyarylene ether nitrile (PEN) as building components. The PEN was copolymerized through phenolphthalin and AIE-gen (4, 4′-(1, 2-di (4-hydroxyphenyl)-1, 2-diyl) diphenol), wherein AIE-gen endowed the copolymer with AIE effect so that the copolymer could aggregate correspondingly in different solvent/nonsolvent systems and produce fluorescence enhanced. In these experiments, the diameter of Fe3O4/PEN hybrid microspheres was controlled by the volume proportion of nonsolvent (ethylene glycol (EG)) and solvent (N-methyl pyrrolidone (NMP)) in preparation process based on the aggregation behavior of AIE active PEN. Moreover, the resulted hybrid microspheres also had excellent magnetic and electromagnetic absorption performance. Specifically, they all exhibited a strong reflection loss peak both in the low and high frequency range. Meanwhile, with the change of coating thickness, these hybrid microspheres had a wide wave-absorbing frequency from 5 GHz to16 GHz. The results supported that the hybrid microspheres integrated with magnetism and AIE property will have a wide application in the preparation and improvement of size-controlled inorganic organic nanocomposites.

Interface Engineering Strategies for Fabricating Nanocrystal-Based Organic–Inorganic Nanocomposites

Hybrid organic–inorganic nanocomposites have attracted considerable attention because they have the advantages of both conjugated polymers (CPs) and nanocrystals (NCs). Recent developments in the interfacial engineering of CP–NC organic–inorganic nanocomposites enabled the formation of an intimate contact between NCs and CPs, facilitating electronic interactions between these two constituents. To design CP–NC nanocomposites, several approaches have been introduced, including ligand refluxing, direct grafting methods, direct growth of NCs in proximity to CPs, and template-guided strategies. In this review, the general reactions of ligand exchange processes, purification methods, and characterization techniques have been briefly introduced. This is followed by a highlight of recent advances in the synthesis of hybrid CP–NC nanocomposites and newly developed inorganic surface treatments, as well as their applications. An outlook for future directions in this area is also presented.

CuNPs-magadiite/chitosan nanocomposite beads as advanced antibacterial agent: Synthetic path and characterization

In this work, an inorganic-organic nanocomposite was prepared by combining copper exchanged-magadiite (Cu-magadiite) with chitosan. The synthesis was carried out by direct dispersion of the Cu-magadiite in the chitosan matrix. The mixture obtained is shaped into beads with an average diameter of about 1–1.2 mm. These beads were then contacted with a solution of NaBH4 in order to reduce loaded copper ions into copper nanoparticles species. The resulting nanocomposite (Cu-NPs-magadiite/chitosan) was characterized by XRD, FTIR, SEM, TG, UV–visible DR and EDX analysis. The results show that the magadiite was completely exfoliated confirming the formation of the organic-inorganic composite. Indeed, the encapsulation of magadiite was confirmed by the SEM images, which is presented as micron free aggregates included in the cavities of a continuous polysaccharide matrix. Otherwise, they confirm also the formation of CuNPs which are probably immobilized inside the magadiite-chitosan solid matrix. The antibacterial activity against E. coli and S. aureus was highlighted by the disc inhibition method and the minimum inhibitory concentration (MIC) was determined. The CuNPs-magadiite/chitosan nanocomposite showed a very efficient bactericidal effect against both pathogen bacteria. Additionally, the MIC values obtained for nanocomposite are of 0.25 μg/L against S. aureus and of 0.50 μg/L against E. coli.

Role of conducting polyaniline interphase on the low field magnetoresistance for LSMO-PANI nanocomposites

The aim of the present report is to show the synergistic effect of conducting polyaniline and manganite nanoparticles on the low field magnetoresistance response. We specially focused on the role of the conducting polyaniline interphase in a broad range of temperatures and low applied magnetic fields. Our results showed an increment on the electrical conductivity and enhancement on the magnetoresistance for lower amounts of conducting polyaniline additions with respect to the manganite unloaded samples. We also found that close to room temperature, the changes in magnetoresistance are mostly due to an increment of the spin polarization and spin disorder due to the presence of polyaniline interphase. However, at intermediate temperatures the polyaniline interphase intrinsic magnetoresistance showed an additional contribution to the total negative magnetoresistance response. These results, suggest that conducting polymer interphase shows both passive and active roles in the enhancement of the low field magnetoresistance of inorganic-organic nanocomposites.

Bifunctional urchin-like WO3@PANI electrodes for superior electrochromic behavior and lithium-ion battery

A improved bifunctional nanostructure composite was designed and fabricated as reversible electrodes for electrochromic film and lithium-ion battery. This unique optic-electro responsive urchin-like architecture assembled from WO3@PANI nanobelts were prepared by solvothermal and electropolymerization methods. As expected, the composite exhibits the superior optical-electrochemical performances. The composite owns quick switching time ranging from purple, green, yellow, gray to blue via voltage regulation, better rate performance and long-term cycling stability in the galvanostatic charge/discharge process. Benefited from stable structure and short diffusion path, it also demonstrates a distinct optical modulation (△T = 45%) and excellent durability after long-term cycles (1200 cycles). The as-prepared electrode exhibits outstanding cycling stability (capacity retention of 516 mAh g−1 after 1200 cycles with a low average fading capacity of ca. 0.103 mAh g−1 and fading cyclic rate of ca. 0.02% per cycle). The long-term stability studies reveal that urchin-like composite has much more excellent optical and electrochemical durability. The morphology and structure of the composite were carried out by characterization equipment. This effective synthesis strategy will have profound implications for developing the other inorganic–organic nanocomposites in optical and electrochemical field.

Rapid and destructive adsorption of paraoxon-ethyl toxin via a self-detoxifying hybrid electrospun nanofibrous membrane

Hierarchical organic-inorganic nanocomposites derived from polyethersulfone (PES) nanofibrous membranes with a post-modification of dopamine (DA) and polyethylenimine (PEI), comprising a high content (33 wt%) of MgO nanoparticles of smaller dimensions (12.7 ± 3.0 nm), were successively fabricated using electrospinning and DA/PEI self-polymerization methods. The obtained hybrid membranes have a rapid capture and great destructive capacity towards paraoxon-ethyl toxin degradation with a relatively short interaction time (up to 92% within 40 min) for effective environmental remediation.

Facile preparation of multifunctional carbon nanotube/magnetite/polyaniline nanocomposite offering a strong option for efficient solid-phase microextraction coupled with GC-MS for the analysis of phenolic compounds.

The aim of this study was to synthesize a highly efficient organic-inorganic nanocomposite. In this research, the carbon nanotube/magnetite/polyaniline nanocomposite was successfully prepared through a facile route. Monodisperse magnetite nanospheres were prepared through the coprecipitation route, and polyaniline nanolayer as a modified shell with a high surface area was synthesized by an in situ growth route and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The prepared nanocomposite was immobilized on a stainless-steel wire for the fabrication of the solid-phase microextraction fiber. The combination of headspace solid-phase microextraction using carbon nanotube/magnetite/polyaniline nanocomposite fiber with gas chromatography and mass spectrometry can achieve a low limit of detection and can be applied to determine phenolic compounds in water samples. The effects of the extraction and desorption parameters including extraction temperature and time, ionic strength, stirring rate, pH, and desorption temperature and time have been studied. Under the optimum conditions, the dynamic linear range was 0.01-500ng/mL and the limits of detection of phenol, 4-chlorophenol, 2,6-dichlorophenol, and 2,4,6-trichlorophenol were the lowest (0.008ng/mL) for three times. The coefficient of determination of all calibration curves was more than 0.990.

Metal Nanoparticle Carbon Gel Composites in Environmental Water Sensing Applications.

The synthesis of organic-inorganic nanocomposites that can interact with different environmental pollutants and can be mass-produced are very promising materials for the fabrication of chemical sensor devices. Among them, metal (or metal oxide) nanoparticles doped conductive porous carbon composites can be readily applied to the production of electrochemical sensors and show enhanced sensitivity for the measurement of water pollutants, thanks to the abundant accessible and functional sites provided by the interconnected porosity and the metallic nanoparticles, respectively. In this personal account, an overview of several synthesis routes of porous carbon composites containing metallic nanoparticles is given, paying special attention to those based on sol-gel techniques. These are very powerful to synthesize hybrid porous materials that can be easily processed into powders and thin films, so that they can be implemented in electrode fabrication processes based on screen-printing and lithography techniques, respectively. We emphasize the sol-gel routes developed in our group for the synthesis of bismuth or gold nanoparticle doped porous carbon composites applied to fabricate electrochemical sensors that can be scaled down to produce miniaturized on-chip sensing devices for the sensitive detection of heavy metal pollutants in water. The trend towards the miniaturization of electrochemical sensors to be readily employed as analytical tools in environmental monitoring follow the market requirements of rapid and accurate on-site analysis, small sample consumption and waste production, as well as potential for continuous or semi-continuous in-situ determination of a wide variety of target analytes.

Marvelous abilities for polyhedral oligomeric silsesquioxane to improve tribological properties of polyamide-imide/polytetrafluoroethylene coatings

POSS-doped organic–inorganic nanocomposites (POSS referring to polyhedral oligomeric silsesquioxane) as a new generation of high-performance materials are of special significance, since they simultaneously possess the high rigidity and stability of inorganic species as well as the desired flexibility, ductility and processability of polymer species. Thus, octa(3-amino propyl) POSS (amino-functionalized POSS, denoted as NH2-POSS) was incorporated into polyamide-imide (denoted as PAI) to obtain a series of NH2-POSS/PAI hybrid composites. The molecular structures of NH2-POSS and NH2-POSS/PAI hybrid composites were analyzed by Fourier transform infrared spectrometry and X-ray diffraction. The impact of NH2-POSS on the thermal stability and mechanical properties of PAI as well as the tribological properties of PAI/PTFE-based (PTFE referring to polytetrafluoroethylene) bonded solid lubricant coatings was investigated. Findings indicate that the introduction of a proper amount of NH2-POSS leads to an increase in the glass transition temperature (Tg) as well as hydrophobicity and microhardness of PAI. Besides, NH2-POSS contributes to reducing the friction coefficient and wear rate of PAI/PTFE-bonded solid lubricant coatings. Particularly, the introduction of 7% (mass fraction) of NH2-POSS leads to a decrease in the wear rate of PAI/PTFE-bonded solid lubricant coating by about 50%. This could be attributed to the increase in the load-bearing capacity and decrease in the surface energy of the polymer matrix coatings upon the addition of NH2-POSS.

Fully Printed Organic-Inorganic Nanocomposites for Flexible Thermoelectric Applications.

Thermoelectric materials, capable of interconverting heat and electricity, are attractive for applications in thermal energy harvesting as a means to power wireless sensors, wearable devices, and portable electronics. However, traditional inorganic thermoelectric materials pose significant challenges due to high cost, toxicity, scarcity, and brittleness, particularly when it comes to applications requiring flexibility. Here, we investigate organic–inorganic nanocomposites that have been developed from bespoke inks which are printed via an aerosol jet printing method onto flexible substrates. For this purpose, a novel in situ aerosol mixing method has been developed to ensure uniform distribution of Bi2Te3/Sb2Te3 nanocrystals, fabricated by a scalable solvothermal synthesis method, within a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate matrix. The thermoelectric properties of the resulting printed nanocomposite structures have been evaluated as a function of composition, and the power factor was found to be maximum (∼30 μW/mK2) for a nominal loading fraction of 85 wt % Sb2Te3 nanoflakes. Importantly, the printed nanocomposites were found to be stable and robust upon repeated flexing to curvatures up to 300 m–1, making these hybrid materials particularly suitable for flexible thermoelectric applications.

POSS-containing hybrid nanomaterials based on thiol-epoxy click reaction

Organic-inorganic nanocomposites were designed by combining a commercial epoxy resin (diglycidyl ether of bisphenol A - DER) and a multi-thiol crosslinking agent with a “clickable” polyhedral oligomeric silsesquioxane (POSS) compound. 1-methylimidazole was employed as a catalyst to yield highly efficient thiol-Michael addition reaction materials. The equivalent ratio between epoxy: thiol was maintained 1:1 in all the formulations and therefore the homopolymerization reaction of epoxy resin is unlikely to occur. The synergistic effect of the thiol compound and mono-functionalized POSS bearing one epoxy/thiol reactive group on the curing process was investigated in detail. We assume that the mechanistic pathway of the thiol-epoxy click-reaction increases in complexity due to the introduction of reactive POSS in the system. The incorporation of mono-epoxy or mono-thiol POSS in the thiol–epoxy organic host leads to distinct thermo-mechanical behavior of the crosslinked networks due to the fact that the POSS compound will chemically interact in the click reaction.

Gel polymer electrolyte based on polymethyl methacrylate matrix composited with methacrylisobutyl-polyhedral oligomeric silsesquioxane by phase inversion method

A kind of organic-inorganic nanocomposite of methacrylisobutyl-polyhedral oligomeric silsesquioxane (MA-POSS) is synthesized and the nanocomposite as the modified filler is introduced into polymethyl methacrylate (PMMA) matrix to prepare gel polymer electrolyte (GPE) membrane used in lithium ion battery (LIB) through phase inversion method combined with liquid electrolyte adsorption. The results reflect that compared to the solvent evaporation technique, the electrochemical performances of the GPE corresponding to the membrane prepared by phase inversion method are more outstanding. Besides, the membrane also shows good mechanical strength. Compared to the GPE based on pure PMMA matrix, the comprehensive performances of the modified GPE are also enhanced a lot and the GPE with the mass of 10% MA-POSS exhibits the most favorable properties. The excellent performances are shown as follows: the ionic conductivity reaches to 2.77 × 10−3 S cm−1 at room temperature; the lithium ion transfer number is up to 0.40; the GPE is electrochemical stable below 5.5 V (vs. Li/Li+); the compatibility between GPE and lithium anode is satisfying and the ionic conductivity obeys the Arrhenius behavior.

Transport and Relaxation of Charge in Organic-Inorganic Nanocomposites

Transport and Relaxation of Charge in Organic-Inorganic Nanocomposites

Solution-Processed Interfacial PEDOT:PSS Assembly into Porous Tungsten Molybdenum Oxide Nanocomposite Films for Electrochromic Applications.

Electrochromic devices (ECDs) have received increased attention for applications including optoelectronics, smart windows, and low-emission displays. However, it has been recognized that the ECDs with transition-metal oxide (TMO) electrodes possess a high charge transport barrier because of their poor electrical conductivity, which limits their electrochromic performance. In this work, we addressed this limitation by utilizing a conjugated polymer to fabricate an organic-inorganic nanocomposite film that decreases the charge transport barrier of typical TMO electrodes. Using a conventional spray-layer-by-layer (spray-LbL) deposition technique, we demonstrate an electrochromic film composed of porous layers of tungsten molybdenum oxide (W0.71Mo0.29O3) nanorods permeated with an interconnected conductive layer of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The introduction of PEDOT:PSS is shown to significantly reduce the charge transport barrier, allowing the nanocomposite W0.71Mo0.29O3/PEDOT:PSS electrode to exhibit significantly improved electrochromic switching kinetics compared with the deposited W0.71Mo0.29O3 films. Furthermore, the optical contrast of the nanocomposite electrode was observed to be superior to both pure PEDOT:PSS and W0.71Mo0.29O3 electrodes, with a performance that exceeded the linearly predicted contrast of combining the pure films by 23%. The enhanced performance of the PEDOT:PSS-intercalated porous W0.71Mo0.29O3 nanocomposite electrodes and the facile synthesis through a spray-LbL method demonstrate a viable strategy for preparing fast assembling high-performance nanocomposite electrodes for a wide variety of electrochemical devices.

UV-curable urethane acrylate zirconium oxide nanocomposites: Synthesis, study on viscoelastic properties and thermal behavior

In the present study, UV-curable urethane acrylate was synthesized by the reaction of isophorone diisocyanate with1,4-butanediol and 2-hydroxyethyl methacrylate in the presence of dibutyltin dilaurate as a catalyst and acetone as a solvent. The structure of urethane acrylate oligomer was characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. In order to examine the influence of inorganic phase of zirconium oxide nanoparticles on characteristics of synthesized resin, organic–inorganic nanocomposites were prepared by urethane acrylate resin and nano zirconium oxide with 1, 3, and 5 wt%. In order to improve nanoparticles dispersion, the surface of zirconium oxide nanoparticles was modified by vinyltrimethoxysilane coupling agent. The analysis of nanoparticle surface modification by Fourier transform infrared spectroscopy and scanning electron microscopy suggested a good reaction of vinyltrimethoxysilane with the surface of zirconium oxide nanoparticles. The characteristics of the prepared nanocomposites were evaluated through thermogravimetric analysis and dynamic mechanical thermal analysis. All of conducted tests represented improved thermal stability properties, storage modulus, and viscoelastic properties of urethane acrylate–zirconium oxide nanocomposites in comparison with polymeric coatings without nanoparticles.

Interfacial Coupling Effect in Organic/Inorganic Nanocomposites with High Energy Density.

Organic/inorganic nanocomposites (OINs) can be potentially used as high-performance capacitors due to their rapid charge-discharge capability along with respectable power density. The coupling effect of the filler/matrix interface plays a prominent role in the dielectric and electric properties of OINs. Along with a review of contemporary theoretical models, recent advances in interfacial optimization to improve energy density through careful interface control and design are also presented. Possible mechanisms that may improve energy density and potential applications for high-energy-density capacitors are also highlighted.

Preparation of organic-inorganic hybrid nanocomposites from chemically modified epoxy and novolac resins and silica-attached carbon nanotubes by sol-gel process: Investigation of thermal degradation and stability

Abstract Hear, three hybrid composites with high char yield and thermal stability were prepared form tetraethyl orthosilicate (TEOS)-modified epoxy resin (MER), (3-glycidyloxypropyl) trimethoxysilane (GPTES)-modified novolac resin (MNR), epoxidized novolac resin (ENR), and silica-grafted carbon nanotube (SFCNT) by a sol-gel method. The first class was prepared from MER and SFCNT. The second class was prepared from MER, MNR, and SFCNT. And the third class was prepared from MNR, ENR, and SFCNT. TEOS was used as covalent coupling agent in the sol-gel process. Results of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed successful modification of epoxy and novolac resins, modification of silica nanoparticles with (3-Aminopropyl)triethoxysilane (APTES), and also functionalization of CNT with amine-modified silica nanoparticles. Results of thermogravimetric analysis confirmed that the hybrid composite containing 4 wt% of SFCNT, MNR, and ENR shows the highest char yield of 58.4%. The hybrid composite containing 4 wt% of SFCNT and MER shows the highest degradation temperature of 442.7 °C. Finally, the hybrid composite formed from 4 wt% of SFCNT, MER, and MNR shows degradation temperature of 439.0 °C and char yield of 47.2%. Microscopic images and X-ray diffraction results confirmed attachment of silica particles at the surface of CNT by chemical bonding.

Thermoelectric Properties of Co-doped ZnO by Incorporating Organic Nanoparticles

Organic-inorganic nanojunction can result in a selective scattering of charge carrier depending on their energy, which leads to a simultaneous increase in Seebeck coefficient S and power factor PF when the Fermi levels of the constituent materials are aligned appropriately. In this work, the nanojunction was employed at the organic-inorganic semiconductor interface of polyparaphenylene (PPP) and Zn 1- x Co x O nanoparticles through a sol-gel method. The resulting Zn 0.925 Co 0.075 O/9wt% PPP hybrids exhibit a high power factor due to the largest electrical conductivity and higher Seebeck coefficient. Moreover, organic-inorganic nano-interface effectively reduces the thermal conductivity by interface scattering of phonons. All these effects finally lead to a thermoelectric figure of merit, ZT up to 0.22 in these inorganic-organic nanocomposites, which corresponds to a 5-fold enhancement compared to that of the Zn 0.925 Co 0.075 O matrix. This work demonstrates the effectiveness of nanojunctions and provides a rational route to high performance thermoelectrics in a bulk material.