Solvent Mixing Method Research Articles

Facile synthesis of ceria nanoparticles by precipitation route for UV blockers

Homogeneous ceria (CeO2) nano particles of approximately 4nm have been successfully synthesized via a simple precipitation route by employing the mixed solvent method. X-ray diffraction analysis revealed the precipitate particles to be of highly crystalline nature with face centered cubic structure along (111) (200) (220) (311) (400) (331) (422) (511) planes. Cerium oxide nanoparticles exhibits enhanced specific surface area of about 139.116 m2/g. The mono-dispersed spherical shape morphology of approximately 4nm particles was confirmed using TEM analysis and its chemical composition by SEM–EDS analysis. Surface morphology reveals the smooth surface with an average roughness of 14.9nm with the help of AFM. Raman studies show a characteristic peak at 464cm−1. The UV absorption edge was found at 314nm i.e. In the Ultra Violet region suggesting that the material has a good absorption of UV light. Also, it shows an excellent transparency in the visible region.

Adsorption of acid red from dye wastewater by Zn2Al-NO3 LDHs and the resource of adsorbent sludge as nanofiller for polypropylene

In this contribution, we report the removal of acid red 97 (AC97) from simulated dye wastewater by using Zn2Al-NO3 layered double hydroxides (LDHs) adsorbent, and the resource of the LDH adsorbent sludge as nanofiller for polypropylene (PP) for the first time. The obtained Zn2Al-NO3 LDH was analyzed using X-ray diffraction and scanning electron microscopy analysis, confirming the formation of pure and platelike LDH nanoparticles. The effects of adsorption time and initial dye concentration on the removal of AC97 from wastewater were systematically investigated, showing that the Zn2Al-NO3 LDHs is very efficient in removing AC97. The saturated adsorption capacity of water washed and acetone washed Zn2Al-LDHs is 204.4 and 299.5 mg/g, respectively. Finally, the LDH adsorbent sludge was added into PP using a modified solvent mixing method. Thermal gravimetric analysis and ultraviolet (UV) absorption analysis of PP/Zn2Al-AC97 LDHs nanocomposites suggested that the Zn2Al-AC97 LDH can significantly improve the thermal stability and UV shielding ability of PP. This data demonstrated that it is very promising to resource the dye adsorbent sludge as multifunctional nanofiller for polymers.

A facile approach for the synthesis of magnetic separable Fe3O4@TiO2, core–shell nanocomposites as highly recyclable photocatalysts

A facile and efficient approach for the fabrication of Fe3O4@TiO2 nanocomposites with a good core–shell structure has been demonstrated. The approach employed involved the coating of successive titania shell on Fe3O4 core using a mixed solvent method with the catalysis of ammonia followed by the crystallization of TiO2 through solvothermal method. The as-obtained core–shell structure was composed of a central Fe3O4 core with a strong response to external fields, whereas the outer titanium oxide coating was useful for the degradation of organic contaminants. The results showed that Fe3O4@TiO2 nanocomposites exhibited high degree of crystallinity, excellent magnetic properties at room temperature. Furthermore, the as-prepared Fe3O4@TiO2 nanocomposites exhibited good photocatalytic activity toward the degradation of Rhodamine B (RhB) solution, which meant that they can be used as efficient and conveniently recoverable photocatalysts. In addition, the mechanism of coating by ammonia catalysis was also investigated.

Solvothermal preparation of flower-like ZnS microspheres, their photoluminescence and hydrogen absorption characteristics

The complex 3D flower-like ZnS microspheres have been synthesized via a one-pot template-free solvothermal method in mixed solvents of ethylenediamine, ethanolamine and ethanol without any surface-active agent. The prepared nanostructures have been characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The FESEM, TEM and HRTEM results exhibit that the 3D ZnS architectures present flower-like microstructures self-assembled with aligned high-density nanosheets. The XRD results show that the flower-like ZnS microspheres are wurtzite structure and highly crystalline. The photoluminescence spectrum of the flower-like ZnS microspheres exhibits a strong broad defect related band at 400–600nm which almost covered the whole visible region. The first ever study on hydrogen absorption characteristics of the ZnS microspheres performed at 373K shows an absorption capacity of 0.84wt%.

Synthesis of complex 3D ZnS architectures via a template-free solvothermal approach and the optical properties

The complex 3D ZnS architectures have been synthesized through the template-free solvothermal method in mixed solvents of ethylenediamine, ethanolamine and distilled water without any surface-active agent. The morphology, phase structure, composition and optical properties of the product have been characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and photoluminescence spectra (PL), the results show that the as-prepared complex 3D ZnS architectures show wurtzite structure and are highly crystalline. In addition to violet-blue band at 400–470nm which has been observed by many researchers in pure ZnS nanostructures, an extra strong yellow peak at around 570nm has been observed in the as-prepared sample, which usually observed in Mn-doped ZnS nanostructures. The mechanism has been discussed.

Synthesis of Flame-Retardant Polypropylene/LDH-Borate Nanocomposites

New nanocomposites have been prepared using unmodified polypropylene (PP) and a new type of highly dispersed [Zn2Al(OH6)][B4O5(OH)4]0.5 (Zn2Al-borate) and [Mg3Al(OH)8][B4O5(OH)4]0.5 (Mg3Al-borate) layered double hydroxides (LDHs). PP/LDHs nanocomposites with LDH loadings of 1, 3, 6, 9, 15, and 30 wt % have been prepared by a novel solvent mixing method. Scanning electron microscopy (SEM) analysis shows that the precipitated nanocomposites materials form spherical particles with an average size of ca. 10 μm and that the LDH nanoparticles were well dispersed within the PP matrix. XRD analysis of the nanocomposites indicates that the LDHs are completely exfoliated. The thermal stability and flame retardancy properties of these new materials have been evaluated as a function of the nature of LDH and the LDH loadings. Cone calorimetry analysis indicates that PP/Zn2Al-borate nanocomposites exhibited superior performance than the equivalent PP/Mg3Al-borate nanocomposites; a 15 wt % of the highly dispersed Zn2Al-...

A covalent route for efficient surface modification of ordered mesoporous carbon as high performance microwave absorbers

A covalent route has been successfully utilized for the surface modification of ordered mesoporous carbon (OMC) CMK-3 by in situ polymerization and grafting of methyl methacrylate (MMA) in the absence of any solvent. The modified CMK-3 carbon particles have a high loading of 19 wt% poly(methyl methacrylate) (PMMA), named PMMA-g-CMK-3, and also maintain their high surface area and mesoporous structure. The in situ polymerization technique endows a significantly enhanced electric conductivity (0.437 S m(-1)) of the resulting PMMA-g-CMK-3/PMMA composite, about two orders of magnitude higher than 1.34 × 10(-3) S m(-1) of PMMA/CMK-3 obtained by the solvent mixing method. A minimum reflection loss (RL) value of -27 dB and a broader absorption band (over 3 GHz) with RL values <-10 dB are obtained for the in situ polymerized PMMA-g-CMK-3/PMMA in a frequency range of 8.2-12.4 GHz (X-band), implying its great potential as a microwave absorbing material. The maximum absorbance efficiency for the in situ polymerized sample increases remarkably compared to that (-10 dB) of CMK-3/PMMA prepared by the solvent mixing method. Changing the thickness of the absorber can efficiently adjust the frequency corresponding to the best microwave absorbance ability. The enhanced microwave absorption by the surface modified CMK-3 is ascribed to high dielectric loss. This in situ polymerization for the surface modification of mesoporous carbons opens up a new method and idea for developing light-weight and high-performance microwave absorbing materials.

Synthesis of polypropylene/Mg3Al–X (X = CO32−, NO3−, Cl−, SO42−) LDH nanocomposites using a solvent mixing method: thermal and melt rheological properties

In this contribution, polypropylene (PP) nanocomposites with four different inorganic anion (CO32−, NO3−, Cl−, and SO42−) intercalated Mg3Al layered double hydroxides (LDHs) as nanofillers were prepared using a solvent mixing method for the first time. The influence of interlayer inorganic anions on the thermal stability, melting and recrystallisation behavior and rheological property of PP was then systematically compared. The thermal stability was significantly improved, with Mg3Al–CO3 and Mg3Al–Cl LDHs, and T0.5 increased by about 44 °C compared to pure PP. The incorporation of LDHs increased the melting temperature (Tm) and the recrystallization temperature (Tc) of PP by about 3–4 °C and 10–13 °C, respectively. The influence on the storage modulus (G′) and loss modulus (G′′) follows the order of Mg3Al–SO4 > Mg3Al–NO3 > Mg3Al–CO3 > Mg3Al–Cl. Although the incorporation of all LDHs led to an improvement in the thermal stability, Tm, Tc, G′, G′′, and complex viscosity of PP/Mg3Al–X LDH nanocomposites, the extent of changes varied with the type of inter-layer anions. The study finally demonstrated that even very similar inorganic anions such as CO32−, NO3−, Cl−, and SO42− could lead to a significant difference in the property of the synthesized PP/LDH nanocomposites, and it must be taken into account for the future design of polymer/LDH nanocomposites.

Polypropylene/Mg3Al–tartrazine LDH nanocomposites with enhanced thermal stability, UV absorption, and rheological properties

We report the synthesis of coloured polypropylene (PP)/Mg3Al–tartrazine layered double hydroxide (LDH) nanocomposites with enhanced thermal stability, UV absorption capacity, and rheological properties using a modified solvent mixing method for the first time. SEM images indicated that the LDH nanoparticles were evenly dispersed within the PP matrix due to the favourable interactions between PP and LDHs. TGA and DSC analysis indicated that the thermal stability of PP/LDH nanocomposites was significantly increased. Decreased G′ and G′′ ascribed to the enhanced mobility (relaxation) of the confined polymer chains at the interface of the PP/LDH layers suggested that the LDH is nano-dispersed in the composites. UV-Vis spectroscopy showed that the addition of Mg3Al–tartrazine LDH significantly enhanced the UV absorption characteristics of PP. Since tartrazine is a nontoxic additive, these coloured PP/Mg3Al–tartrazine LDH nanocomposites are expected to have many promising applications such as for food packing and children's toys, etc.

Fabrication and characterizations of PCDTBT: PC71BM bulk heterojunction solar cell using air brush coating method

Organic solar cells have been significantly attracted due to the need to develop an inexpensive clean and sustainable renewable energy source. We report on the fabrication of poly [N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]/[6, 6]-phenyl-C71-butyric acid methyl ester blend active layer using airbrush spray-coating method in mixed solvents. Optical absorption of the active layers was analyzed using UV–visible spectral studies in the wavelength range from 300 to 800 nm. The surface morphology of the active layers deposited with different parameters (spraying time and substrate-nozzle distance) was examined using atomic force microscopy. The current density–voltage (J–V) characteristics of photovoltaic cells were measured under the illumination of simulated solar light with 100 mW cm−2 (AM 1.5G) by an Oriel 1000 W solar simulator. The power conversion efficiency of the solar cell is more than 5 %.

Sodium polyacrylate modified Fe3O4 magnetic microspheres formed by self-assembly of nanocrystals and their applications

Sodium polyacrylate modified Fe3O4 magnetic microspheres (SPMFMs) formed by self-assembly of nanocrystals were synthesized by a solvothermal method in mixed solvents of ethylene glycol and water. The SPMFMs exhibited a quasi-superparamagnetic behavior, and the saturation magnetization reached as high as 81.6emu/g. The potential applications of the SPMFMs in the magnetic resonance imaging (MRI), drug delivery and waste water treatment were investigated. The loading capacity of the SPMFMs for bovine hemoglobin was 95mg/g, and 33% of the loaded bovine hemoglobin was released in a period of 75h. The adsorption for methylene blue and fuchsin basic using the SPMFMs as the adsorbent in the waste water treatment was efficient and rapid (within 1min). The SPMFMs after the adsorption of the organic pollutants could be recycled and reused effectively with a slightly reduced adsorption capacity.

Highly Conductive Nanocomposites with Three‐Dimensional, Compactly Interconnected Graphene Networks via a Self‐Assembly Process

AbstractPolymer‐based materials with high electrical conductivity are of considerable interest because of their wide range of applications. The construction of a 3D, compactly interconnected graphene network can offer a huge increase in the electrical conductivity of polymer composites. However, it is still a great challenge to achieve desirable 3D architectures in the polymer matrix. Here, highly conductive polymer nanocomposites with 3D compactly interconnected graphene networks are obtained using a self‐assembly process. Polystyrene (PS) and ethylene vinyl acetate (EVA) are used as polymer matrixes. The obtained PS composite film with 4.8 vol% graphene shows a high electrical conductivity of 1083.3 S/m, which is superior to that of the graphene composite prepared by a solvent mixing method. The electrical conductivity of the composites is closely related to the compact contact between graphene sheets in the 3D structures and the high reduction level of graphene sheets. The obtained EVA composite films with the 3D graphene structure not only show high electrical conductivity but also exhibit high flexibility. Importantly, the method to fabricate 3D graphene structures in polymer matrix is facile, green, low‐cost, and scalable, providing a universal route for the rational design and engineering of highly conductive polymer composites.

Oxidation of o-chloro and o-hydroxy benzyl alcohols catalyzed by copper (II) tetraphenylporphyrin nanoparticles synthesized by mixed solvent method

. In order to avoid using toxic and dangerous oxidants, oxidative catalytic conversion of organic molecules has been developed in the recent years by using environmentally clean oxidants such as molecular oxygen or hydrogen peroxide. For example, benzyl alcohols have been oxidized by molecular oxygen, because this oxidant only produces water as a by product

Preparation of stable dispersions of layered double hydroxides (LDHs) in nonpolar hydrocarbons: new routes to polyolefin/LDH nanocomposites

We report a simple and cost effective solvent treatment method for the synthesis of a stable and transparent dispersion of the hydrophilic layered double hydroxide, [Mg(6)Al(2)(OH)(16)](CO(3)) in non-polar hydrocarbon solvents. This dispersion can be used to make polyolefin/LDH nanocomposites using a simple solvent mixing method.

PH-sensitive strontium carbonate nanoparticles as new anticancer vehicles for controlled etoposide release

Strontium carbonate nanoparticles (SCNs), a novel biodegradable nanosystem for the pH-sensitive release of anticancer drugs, were developed via a facile mixed solvent method aimed at creating smart drug delivery in acidic conditions, particularly in tumor environments. Structural characterization of SCNs revealed that the engineered nanocarriers were uniform in size and presented a dumbbell-shaped morphology with a dense mass of a scale-like spine coating, which could serve as the storage structure for hydrophobic drugs. Chosen as a model anticancer agent, etoposide was effectively loaded into SCNs based on a simultaneous process that allowed for the formation of the nanocarriers and for drug storage to be accomplished in a single step. The etoposide-loaded SCNs (ESCNs) possess both a high loading capacity and efficient encapsulation. It was found that the cumulative release of etoposide from ESCNs is acid-dependent, and that the release rate is slow at a pH of 7.4; this rate increases significantly at low pH levels (5.8, 3.0). Meanwhile, it was also found that the blank SCNs were almost nontoxic to normal cells, and ESCN systems were evidently more potent in antitumor activity compared with free etoposide, as confirmed by a cytotoxicity test using an MTT assay and an apoptosis test with fluorescence-activated cell sorter (FACS) analysis. These findings suggest that SCNs hold tremendous promise in the areas of controlled drug delivery and targeted cancer therapy.

A Mixed‐Solvent Strategy for Efficient Exfoliation of Inorganic Graphene Analogues

Two are better than one: A mixed-solvent method for liquid exfoliation of MoS2, WS2, and BN nanosheets is presented. Although ethanol and water are both poor solvents for this process, ethanol/water mixtures of appropriate composition, which can be predicted on the basis of Hansen solubility parameters, result in efficient exfoliation (see schematic) to give highly stable suspensions.

Comparative study of lipid extraction from microalgae by organic solvent and supercritical CO2

Pavlova sp. was employed to evaluate the efficiency of different lipid extraction methods. The microalgal crude lipids content determined using the mixed solvent with ultrasonic method was 44.7wt.%. The triglyceride content obtained by the mixed solvent method was 15.6wt.%. The extraction yield was the FAME yield divided by the maximum FAME (15.9wt.%). The extraction yield was improved by cell disruption prior to extraction, and the highest triglyceride extraction yield of 98.7% was observed using the supercritical fluid extraction (SFE) method with bead-beating. The results indicate that the SFE method is effective and provides higher selectivity for triglyceride extraction though the total lipid extracted was less than that using solvent extraction.

Synthesis, characterization and spectral properties of substituted tetraphenylporphyrin iron chloride complexes.

A series of substituted tetraphenylporphyrin iron chloride complexes [RTPPFe(III)Cl, R=o/p-NO2, o/p-Cl, H, o/p-CH3, o/p-OCH3] were synthesized by a novel universal mixed-solvent method and the spectral properties of free base porphyrins and iron porphyrin compounds were compared with each other. The experimental results showed that the one-pot mixed solvent method was superior to the two-step method in the yields, reaction time and workup of reaction mixtures for the synthesis of iron porphyrin compounds. The highest yields (28.7%–40.4%) of RTPPFe(III)Cl were obtained in the mixed solvents propionic acid, glacial acetic acid and m-nitrotoluene under reflux for 2 h. A detailed analysis of ultraviolet-visible (UV-vis), infrared (IR) and far-infrared (FIR) spectra suggested the transformation from free base porphyrins to iron porphyrins. The red shift of the Soret band in ultraviolet-visible spectra due to the presence of p-nitrophenyl substituents and the blue shift of Fe-Cl bond of TPPFeCl in far-infrared spectra were further explained by the electron transfer and molecular planarity in the porphyrin ring.

Mechanical and thermal properties of polypeptide modified hydroxyapatite/poly(L-lactide) nanocomposites

A new type of polypeptide (poly(γ-benzyl-L-glutamate) (PBLG)) modified hydroxyapatite (HA)/poly(L-lactide) (PLLA) nanocomposites (PBLG- g -HA/PLLA) were prepared by the solvent-mixing method, and their mechanical and thermal properties were investigated. The tensile test showed that the mechanical properties of PBLG- g -HA/PLLA nanocomposites were better than that of PLLA, even a 0.3 wt% content of PBLG- g -HA in the nanocomposites could make the tensile strength 12% higher than that of the neat PLLA sample, and the tensile modulus was about 17% higher than that of the PLLA sample. The thermal gravimetric analysis (TGA) showed that the PBLG- g -HA/PLLA composites have better thermal stability than the PLLA sample. The differential scanning calorimetry (DSC) was used to characterize the effect of PBLG- g -HA on the crystallization of PLLA. The isothermal crystallization behavior showed that the half crystallization time (t1/2) of PBLG- g -HA/PLLA was much shorter than that of the PLLA sample. When the PBLG- g -HA content was 10%, t1/2 was only 18.7 min, while t1/2 of the PLLA sample was 61.4 min. The results showed that the PBLG- g -HA worked as a nucleating agent and enhanced the crystallization speed of PLLA.

Nanoscale Morphology Control of Polymer/TiO2 Nanocrystal Hybrids: Photophysics, Charge Generation, Charge Transport, and Photovoltaic Properties

We present a simple approach by using mixed solvent to control the morphology of poly(3-hexylthiophene) (P3HT)/TiO2 nanorod hybrid bulk heterojunction solar cells without any post-treatment. The effects of the controlled morphology on the optical and electrical properties are investigated. It has been a challenge to disperse polar inorganic nanocrystals at a relative high concentration into a relative nonpolar polymer. The use of mixed solvent which consists of pyridine (a poor solvent for P3HT), dichloromethane, and chloroform (a good solvent for P3HT) modifies the nanoscale morphology of P3HT/TiO2 nanorod hybrids, resulting in highly crystalline P3HT domains with well-dispersed TiO2 nanorods within polymer matrix. Study of photophysics reveals that charge carrier could form from emissive species upon photoexcitation and such a process is more efficient in highly ordered P3HT prepared by mixed solvent method. In the P3HT/TiO2 hybrid film, the formation of a bicontinuous phase-separated morphology largely improves charge separation, transport, and recombination in the hybrid devices, which are further supported by time-resolved photoluminescence spectroscopy, carrier extraction by linearly increasing voltage mobility measurement, and transient open-circuit voltage decay measurement, respectively. A result of threefold improvement of the device performance using mixed solvent has been demonstrated compared to that using a single solvent only. This simple process does not need any further thermal post-treatment and is therefore compatible with the room temperature process developed with commonly used plastic substrates for flexible solar cell applications. Our method for morphology control could also be applied to other donor−acceptor hybrid systems as a strategy for device optimization.