One-step Polymerization Method Research Articles

Preparation of magnetic amphiphilic resin microspheres via the one-step polymerization method and extraction of four glucocorticoids for HPLC–MS analysis

Amphiphilic materials can be used for sample preparation of chromatography or mass spectrometry. Amphiphilic materials with magnetic properties in combination with magnetic suction devices allow for automated sample preparation. However, conventional synthesis methods are cumbersome and not suitable for the mass production of the material. In this study, a micro-suspension polymerization method was developed to synthesize magnetic amphiphilic resin microspheres (MARMs), providing new ideas for the preparation of amphiphilic microspheres. MARMs with particle sizes ranging from 3 to 6 μm were successfully prepared, with BET surface area up to 653.2 m2/g. A magnetic solid-phase extraction method based on MARM-5 was developed for the extraction of four glucocorticoids including Cortisone, Hydrocortisone, Cortodoxone, and Corticosterone. This method had a very short adsorption time of 0.5 min and a total extraction time of only 13 min. The limit of detection for the four glucocorticoids ranged from 0.22 to 0.82 ng/L. There was a good linear relationship between sample concentration and peak area in the range of 25∼500 ng/L. Relative recovery of 98 %∼108 % and internal standard normalized matrix effect factors of 95∼114 % were obtained, and the relative standard deviation was between 2.3 % and 6.3 %. The MARMs would be used as excellent solid extraction material for glucocorticoids.

Partial Oxidation of Bio-methane over Nickel Supported on MgO–ZrO2 Solid Solutions

Syngas can be produced from biomethane via Partial Oxidation of Methane (POM), being an attractive route since it is ecofriendly and sustainable. In this work, catalysts of Ni supported on MgO–ZrO2 solid solutions, prepared by a one-step polymerization method, were characterized by HRTEM/EDX, XRD, XPS, H2-TPR, and in situ XRD. All catalysts, including Ni/ZrO2 and Ni/MgO as reference, were tested for POM (CH4:O2 molar ratio 2, 750 ºC, 1 atm). NiO/MgO/ZrO2 contained two solid-solutions, MgO–ZrO2 and NiO-MgO, as revealed by XRD and XPS. Ni (30 wt%) supported on MgO–ZrO2 solid solution exhibited high methane conversion and hydrogen selectivity. However, depending on the MgO amount (0, 4, 20, 40, 100 molar percent) major differences in NiO reducibility, growth of Ni0 crystallite size during H2 reduction and POM, and in carbon deposition rates were observed. Interestingly, catalysts with lower MgO content achieved the highest CH4 conversion (~ 95%), high selectivity to H2 (1.7) and CO (0.8), and low carbon deposition rates (0.024 g carbon.gcat−1 h−1) with Ni4MgZr (4 mol% MgO) turning out to be the best catalyst. In situ XRD during POM indicated metallic Ni nanoparticles (average crystallite size of 31 nm), supported by MgO–ZrO2 solid solution, with small amounts of NiO–MgO being present as well. The presence of MgO also influenced the morphology of the carbon deposits, leading to filaments instead of amorphous carbon. A combustion-reforming mechanism is suggested and using a MgO–ZrO2 solid solution support strongly improves catalytic performance, which is attributed to effective O2, CO2 and H2O activation at the Ni/MgO–ZrO2 interface.

Highly Tough, Stretchable, and Recyclable Ionogels with Crosslink-Enhanced Emission Characteristics for Anti-Counterfeiting and Motion Detection

Traditional luminescent ionogels often suffer from poor mechanical properties and a lack of recyclability and regeneration, which limits their further application and sustainable development. Herein, a luminescent ionogel with strong mechanical properties and good recyclability has been designed and fabricated by introducing dynamic coordination bonds via in situ one-step crosslinking of acrylic acid in ionic liquid of 1-ethyl-3-methylimidazolium diethylphosphate by zinc dimethacrylate. Due to the special crosslinking of dynamic coordination bonds along with the hydrogen bond interaction, the as-prepared ionogel displays excellent stretchability and toughness, good self-adhesiveness, fast self-healability, and recyclability. Interestingly, the obtained ionogels exhibit tunable photoluminescence caused by the crosslink-enhanced emission (CEE) effect from the coordination bonds. Importantly, ionogels can be applied in information storage, information encryption, anti-counterfeiting due to their simple and in situ preparation method, and their special fluorescence performances. Moreover, an ionogel-based wearable sensor has rapid response time and a high gauge factor of 3.22 within a wide strain range from 1 to 700%, which can monitor various human movements accurately from subtle to large-scale motions. This paper offers a promising way to fabricate sustainable functional ionic liquid-based composites with CEE characteristics via an in situ one-step polymerization method.

Tetrapeptide-based mimotope affinity monolith for the enrichment and analysis of anti-HER2 antibody and antibody-drug conjugate

Selective enrichment and analysis of therapeutic antibodies in biological fluids are crucial for the development of biopharmaceuticals. Recently, peptide-based affinity chromatography has exhibited fascinating prospects for antibody enrichment due to the high affinity and specificity of small peptides. However, the post-modification approach of peptide ligands on the material surface is complicated and time-consuming. In this study, a methacrylate modified tetrapeptide (m-EDPW) was firstly demonstrated as the affinity ligand of trastuzumab (Kd = 1.91 ± 1.81 μM). Next, the m-EDPW based affinity monolith was prepared using a facile one-step polymerization method, which could overcome the drawbacks of traditional post-modification preparation strategies. Based on the monolith as described above, a simple enrichment approach was developed under the optimal washing and elution conditions. Based on the excellent properties, such as high porosity (53.09%), weak electrostatic interaction and suitable affinity (1.00 ± 2.14 μM for anti-HER2 ADC), this novel monolith exhibited good specificity and recovery for antibodies (91.6% for trastuzumab, 98.37% for anti-HER2 ADC), and low nonspecific adsorption for human serum albumin (DBC10% = 0.5 mg/g polymer). Particularly, this material was successfully applied to enrich trastuzumab and its related antibody-drug conjugate (ADC) from different cell culture medias. The dynamic tracking analysis of ADC in the critical quality attributes (e.g., charge variants, drug to antibody ratio and subunit conjugation ratio) was also achieved by combining the enrichment approach, capillary electrophoresis or reversed phase liquid chromatography. In summary, the exploited peptide-based mimotope affinity materials showed a great potential for the application in biopharmaceutical analysis.

Role of hemp fiber addition on thermal stability, heat insulation, air permeability and cellular structural features of rigid polyurethane foam

In this current study, rigid polyurethane foams (RPUFs) composites were prepared using different percentage (3, 6, 9 and 12%) of the hemp fibers via one-shut one-step polymerization method. The influences of the hemp fiber addition on the RPUFs were investigated meticulously by means of Fourier-transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), thermal conductivity measurement and scanning electron microscopy (SEM) techniques by evaluating the alternations in the chemical structures of the component, thermal stability, apparent density, insulation performance and cellular topology of the produced samples. The structural analysis revealed that there existed the strong secondary chemical bonds between the functional groups belonging to the components and, depending on that, the improvement in the thermal stability of the foam samples was recorded accompanied by the formation of the better interfacial adhesion. Furthermore, thermal conductivity values of the hemp fiber-loaded RPUFs were observed to increase regularly with the increasing of the content level of the hemp fibers. This was explained by enhancement in the bulk phase conduction level depending of the apparent density rising, reduction in CO2concentration inside cells as well as the formation of the distorted cellular structures. The obtained air permeability results displayed that the hemp fibers incorporated successfully with RPUF structure, which provides the occurrence of the novel micro barriers and pathways limiting the passage of the air throughout the matrix. The taken scanning electron microscopy images also indicated that the cellular morphology and dimensional stability of the produced foams affected negatively by the hemp fiber addition. At high contents, the wrinkled, non-uniform and irregular cellular structures were observed with ruptured and collapsed walls and struts.

Highly Stretchable, Transparent and Adhesive Ionogel Based on Chitosan-Poly(acrylic acid) Double Networks for Flexible Strain Sensors.

A stretchable double-network (DN) ionogel composed of a physically crosslinked network of chitosan (CS) and a chemically crosslinked network of polyacrylic acid (PAA) was prepared in an ionic liquid ([EMIM][OAc]) using a one-step polymerization method. In this ionogel (CS/PAA), the CS and the PAA polymer chains served as backbones, which constructed an interpenetrating DN structure via numerous hydrogen bonds formed through the hydroxyl, amino and carboxyl groups on the polymer chains. The DN structure improves the mechanical properties of the ionogel. Therefore, the CS/PAA DN ionogel exhibited outstanding mechanical performance in many ways: tensile strength up to 2.04 MPa, strain range up to 1046% and the value of toughness up to 8.52 MJ/m3. The ionogel also showed good self-recovery performance, fatigue resistance, ability to work in a broad temperature range (-20~80 °C) and adhesion properties. As a flexible sensor, the CS/PAA DN ionogel showed high strain sensitivity (gauge factor = 6.235). It can sensitively detect human motion (such as joint-bending, vocal fold vibration, walking gait and other human body motions), revealing the practical application potential of flexible electronic devices.

Preparation and characterization of carboxymethyl cellulose/chitosan/alginic acid hydrogels with adjustable pore structure for adsorption of heavy metal ions

In this study, a Pore Structure Control Agent (PSCA) was proposed to adjust the pore structure of hydrogels and quickly solve the problem of heavy metal pollution. PSCA is a mixed solution consisting of Glycerol (GL), Ethyl Orthosilicate (TEOS), Isopropanol (IPA), H2O, and Hydrochloric Acid (HCl). As the addition amount increases, the pore size decreases, and the adsorption capacity first increases and then weakens. PSCS 2 wt% was added, and the adsorption was completed in 20 min. Using borax as a cross-linked agent and coagulant, the heavy metal adsorption hydrogel was prepared by a one-step polymerization method combined with the sol–gel method. The three hydrogels prepared with Carboxymethyl Cellulose (CMC), Chitosan (CS), and Alginic Acid (AA) as raw materials adsorbed Cr(VI), Cu(II), and Ni(II) in a sum greater than 750 mg/g. The kinetic fitting results of Cr(VI) show that the hydrogel belongs to physical adsorption, and Cu(II) and Ni(II) belong to chemical adsorption. The Freundlich adsorption isotherm model indicated that the hydrogel belongs to multilayer adsorption. The proposal of PSCA controls the structure of the hydrogel and has a certain promotion effect on the treatment of heavy metal pollution.

Dopamine-triggered one-step functionalization of hollow silica nanospheres for simultaneous lubrication and drug release

Osteoarthritis (OA) has been regarded as a lubrication deficiency related joint disease. Combination of both joint lubrication and drug intervention may provide a promising nonsurgical strategy for treatment of OA. Developing novel and simple approaches to fabricate superlubricating nanoparticles with drug release property is highly required. Herein, dopamine triggered one-step polymerization method was employed to fabricate polydopamine/poly(3-sulfopropyl methacrylate potassium salt) (PDA—PSPMA) conjugate coating on hollow silica (h-SiO2) nanosphere surfaces to engineer functional nanoparticles (h-SiO2/PDA—PSPMA). The as-prepared h-SiO2/PDA—PSPMA exhibits excellent aqueous lubrication performance on biomaterial substrates as well as natural bovine articular cartilage based on hydration effect of negatively charged PDA—PSPMA coating and “rolling” effect of h-SiO2 nanospheres. In vitro drug loading-release experiments demonstrate that PDA—PSPMA coating functionalized h-SiO2 nanospheres show high drug-loading and sustained-release capability of an anti-inflammatory drug, diclofenac sodium (DS). Such h-SiO2/PDA—PSPMA nanospheres can be potentially used as a synergistic therapy agent for OA treatment combining by simultaneous joint lubrication and drug release.

Adsorption of anionic acid red G dye on polyaniline nanofibers synthesized by FeCl3 oxidant: Unravelling the role of synthetic conditions

Polyaniline (PANI) has been considered as a high-efficient adsorbent for the dye removal from wastewater. Different synthetic conditions could offer PANI with comparable adsorption performance and yield, which are crucial for its large-scale application. Herein, the adsorption performance of PANIs, which synthesized by one-step polymerization method under different temperature and amount of FeCl3, for the removal of a typical anionic dye, Acid Red G (ARG), were investigated. As-synthesized PANIs were characterized by scanning electron microscopy, FT-IR spectroscopy, nitrogen adsorption-desorption isotherms and X-ray diffraction. Adsorption isotherms study result showed that low temperature was beneficial for the formation of highly crystallized PANI nanofibers with high adsorption performance, and high amount of FeCl3 could increase the yield of PANI. An optimal synthetic condition, where temperature is 20 °C and molar of aniline to FeCl3 is 1:4, was determined for PANI when using FeCl3 oxidant (PANIopt). The adsorption including kinetics, isotherms, and regeneration of PANIopt on ARG was then systemically investigated. The maximum adsorption capacity of PANIopt for ARG was found to be 491.20 mg g−1 at 35 °C. Moreover, adsorption mechanism study suggested that the efficient adsorption performance was related with the highly crystalized polymer chain of PANI, which provides abundant active sites for the adsorption of ARG via electrostatic interaction.

Synthesis, characterization, magnetoelectric properties and gas sensing application of Poly(anthranilic acid-co-indole)/ magnetite nanocomposites

The increased demand for the discovery of new conducting materials encourages the researchers for the development of advanced electronic technologies. In the present study, nanocomposites of poly (anthranilic acid- co-indole)/(PANA- C o-PIN) and magnetite nanoparticles (Fe3O4) were prepared via a one-step polymerization method and evaluated by various analytical techniques. The Fourier transform infrared spectroscopy (FT-IR) spectra proved the presence of Fe3O4 nanofillers in the copolymer at 507 cm−1. Optical characterization (UV-Vis) shows a clear blueshift indicating strong interactions between Fe3O4 and PANA- C o-PIN. The X-Ray diffraction (XRD) patterns revealed an increase in crystallinity due to the well dispersed nanoparticles. FESEM images evidenced the morphological changes caused by the uniform dispersion of nanoparticles in the copolymer matrix. The nano-dispersion of magnetite nanoparticles in the copolymer was confirmed by High-resolution transmission electron microscopy analysis. Magnetic properties of nanocomposites obtained from a vibrating sample magnetometer (VSM) showed an increase in the saturation of magnetism with the addition of nanoparticles and the composite exhibited superparamagnetic behaviour. The thermal stability and glass transition temperature of the nanocomposites were greatly enhanced with the addition of nanoparticles and were determined with the help of Thermogravimetric Analysis (TGA) and Differential scanning calorimetry (DSC) respectively. Filler-dependent electrical properties showed a linearly increased DC conductivity with the addition of nanoparticles. The impedance analysis showed that the AC conductivity and dielectric properties of the nanocomposites were higher than the copolymer and the maximum electrical properties were observed for 15 wt.% of composites. The ammonia gas sensing performance of copolymer composite indicates the easy access of gas molecules to the sensor surface through the metal oxide nanoparticles. The synthesized copolymer nanocomposites showed high sensitivity and fast response to ammonia gas. The prepared composite with good thermal properties, dielectric constant, ammonia gas sensing and magnetoelectric properties is a promising candidate for use in nanoelectronics devices.

Biomethane reforming over Ni catalysts supported on PrO2-ZrO2 solid-solutions

Catalysts based on Ni/PrO2-ZrO2 mixtures (PrO2/ZrO2 mass ratio = 1, 4, 8; with Ni 20% of the total weight of catalyst) were synthesized by the one-step polymerization method. They were tested in Dry-Reforming of Biogas (1.5CH4:CO2), Oxidative Reforming of Biomethane (1.5CH4:CO2:0.25 O2), and Partial Oxidation Biomethane (2CH4:1O2). According to the characterization of the catalysts, the XRD results showed the stabilization of tetragonal ZrO2, by forming the PrO2-ZrO2 solid solution; also confirmed by XPS spectroscopy. By SBET analysis, it was found that the higher PrO2 content, increased the surface area (m2 g−1) of the catalysts. The in situ-DRX analyses (under reduction conditions with H2) showed that higher content of PrO2 promoted the decrease in the size of Niº crystallites of the catalysts. According to H2-TPR, the higher content of PrO2 favored the formation of NiO species strongly interacted with support. The catalytic tests showed that the PrO2-ZrO2 solid solution used as catalytic support strongly increased the production of Syngas over Ni-catalysts, and reduced the carbon deposits. The best catalyst was that with 8% PrO2 in the composition (Ni8PrZr), as it recorded the highest reactant conversion rates and the less amount of coke during the reactions. In situ characterization of the catalysts was carried out under reaction conditions (by X-ray absorption spectroscopy), and deactivation was explored. All the results of this research indicated that the use of PrO2-ZrO2 solid solution as catalytic support of Nickel is very promising to Syngas production from clean biomethane and biogas.

Rough surface NiFe2O4@Au/Polydopamine with a magnetic field enhanced photothermal antibacterial effect

Infectious diseases caused by drug-resistant bacteria bring an increasing threat to public health. Thus, finding an effective approach equipped with a synergistic antibacterial performance becomes a critical challenge. This work reports a NiFe2O4@Au/Polydopamine core/shell nanosphere with rough surface, which exhibits a photothermal and magnetolytic coupling antibacterial behavior. The Au/Polydopamine (Au/PDA) hybrid layer, covered on the stable magnetic NiFe2O4 nanosphere by a one-step polymerization method, possesses an excellent photothermal effect. Simultaneously, the superparamagnetic characteristic offers the NiFe2O4@Au/Polydopamine with fantastic magnetolytic force to the biological organism under a rotating external magnetic field. It is found that the NiFe2O4@Au/PDA core/shell nanospheres show good photothermal antibacterial performance (808 nm laser irradiation) on both Escherichia coli and Staphylococcus aureus. Notably, the photothermal antibacterial performance can be significantly improved under applying the rotating magnetic field. This novel photothermal-magnetolytic coupled antimicrobial method supplies a high performance photothermal bactericidal therapy via a remote conduction and reduces the possible damage to normal tissue caused by overheating. Besides bactericidal therapy, the easily and scalable magnetolytic enhancing method is believed to possess high potential in drug delivery, antitumor, and bioseparation.

Optimizing the electromagnetic parameters and microwave absorption of corrosion-resistant FCIP@EP by data-driven discovery

The formation of core–shell structure is one of the standard methods to improve the corrosion resistance of carbonyl iron powders (CIPs). In this manuscript, epoxy resin (EP) was coated on the surface of flaky carbonyl iron particles (FCIPs) by a simple one-step polymerization method to form the FCIP@EP composite particles, and they were used to obtained microwave response to accurately simulate, predict and optimize the microwave absorption performance of composites. After being coated by epoxy resin, the composite exhibits a higher percolation threshold; the absorbing performance is more stable in an acidic environment. The optimal loading of FCIP@EP in the matrix can be obtained by data-driven optimization, and the model calculation results are in good agreement with the actual measured ones. At 23 vol%, the composite's effective absorption bandwidth (EAB, RL < −10 dB) can reach a maximum of 7.63 GHz at 1.5 mm thickness, and the EAB covers all X-band and all Ku-band at 1.9 mm and 1.4 mm, respectively. The whole optimization process provides a guiding basis for the modified corrosion-resistant absorbers in design applications.

Preparation of polydopamine nanofibers mat as a recyclable and efficient adsorbent for simultaneous adsorption of multiple tetracyclines in water

Particle usage form or rigorous and complex preparation procedures limits the practical applications of the most adsorbents for tetracyclines (TCs). Herein, novel polydopamine nanofibers mat (PDA-NFsM) has been simply synthesized by a facile one-step polymerization method. The pH effect, adsorption kinetics, adsorption isotherms, as well as the competitive adsorption behaviors of the three kinds of tetracyclines (TCs), including chlortetracycline hydrochloride (CTC), oxytetracycline (OTC) and tetracycline hydrochloride (TC) on PDA-NFsM has been systematically studied. The mass transfer efficiency of PDA-NFsM is extremely high, almost 88.9%, 85.3% and 82.6% of the equilibrium adsorption capacities of CTC, OTC and TC have been achieved in the first 2 min of the adsorption process, which is superior to many other reported materials. The maximum adsorption capacity of PDA-NFsM for TCs at 25 °C could reach up to 86.2–161.3 mg/g. Furthermore, the possible adsorption mechanisms were studied by theoretical calculation and spectral analysis. Hydrogen bond was proved to be the main interaction mechanism between the adsorbates and the sorbent. As a kind of “monolithic” material, the PDA-NFsM can be easily separated from liquid mediums. Moreover, the excellent reusability endows PDA-NFsM with great value in practical application.

Concentrated hydrogel electrolyte for integrated supercapacitor with high capacitance at subzero temperature

Hydrogel electrolytes with anti-freezing properties are crucial for flexible quasi-solid-state supercapacitors operating at low temperatures. However, the electrolyte freezing and sluggish ion migration caused by the cold temperature inevitably damage the flexibility and electrochemical properties of supercapacitors. Herein, we introduce the concentrated electrolyte into a freeze-casted poly(vinyl alcohol) hydrogel film not only reducing the freezing point of the electrolyte (−51.14 °C) in gels for ensuring the flexibility, but also improving the ionic conductivity of the hydrogel electrolyte (5.92 mS cm−1 at −40 °C) at low temperatures. As a proof, an all-in-one supercapacitor, synthesized by the one-step polymerization method, exhibits a good specific capacitance of 278.6 mF cm−2 at −40 °C (accounting for 93.8% of the capacitance at room temperature), high rate performance (50% retention under the 100-fold increase in current densities), and long cycle life (88.9% retention after 8,000 cycles at −40 °C), representing an excellent low-temperature performance. Our results provide a fresh insight into the hydrogel electrolyte design for flexible energy storage devices operating in the wide range of temperature and open up an exciting direction for improving all-in-one supercapacitors.

Synthesis of 14C-labelled polystyrene nanoplastics for environmental studies

Available analytical methods cannot detect nanoplastics at environmentally realistic concentrations in complex matrices such as biological tissues. Here, we describe a one-step polymerization method, allowing direct radiolabeling of a sulfonate end-capped nano-sized polystyrene (nPS; proposed as a model nanoplastic particle representing negatively charged nanoplastics). The method, which produces nanoplastics trackable in simulated environmental settings which have already been used to investigate the behavior of a nanoplastic in vivo in a bivalve mollusc, was developed, optimized and successfully applied to synthesis of 14C-labeled nPS of different sizes. In addition to a description of the method of synthesis, we describe the details for quantification, mass balance and recovery of the labelled particles from complex matrices offered by the radiolabelling approach. The radiolabeling approach described here, coupled to use of a highly sensitive autoradiographic method for monitoring nanoplastic body burden and distributions, may provide a valuable procedure for investigating the environmental pathways followed by negatively charged nanoplastics at low predicted environmental concentrations. Whether the behaviour of the synthetic nPS manufactured here, synthesised using a very common inititator, represents that of manufactured nPS found in the environment, remains to be seen.

Synthesis and characterization of a series of cross-linked polyamines for removal of Erichrome Black T from aqueous solution

• Synthesis of four cross-linked terpolymers by one-step polymerization method. • Characterization of the polymers by various techniques. • High EBT adsorption capacities of 775 mg/g and 917 mg/g by two polymers. • Equilibrium, kinetic and Thermodynamics studies. • Polymers show promising reusability. A new series of polymers comprising four terpolymers was synthesized via Mannich polycondensation of benzene-1,4-diamine, formaldehyde and piperazine by varying the benzene-1,4-diamine and piperazine ratio. The new polyamines (labeled Dipip) were characterized using 13 C solid-state NMR, FT-IR, TGA, DSC, XRD, SEM and EDX. The adsorptive performances of the synthesized polymers for Erichrome Black T (EBT) uptake from aqueous solution were investigated under batch process. Equilibrium, kinetic, and thermodynamic studies were conducted to determine the influence of different operational parameters of the adsorption process. The two most promising polymers among the series show an excellent EBT removal efficiency of ~100% and ~95% with high adsorption capacities of 775 mg·g −1 and 917 mg·g −1 , respectively at a meager dosage of 5 mg. The sorption of EBT on the polymers was well described by Redlich-Peterson & Langmuir model while the kinetic studies indicate that pseudo-second order model was followed. For the thermodynamic studies, the negative Δ G and positive Δ H values obtained suggest a spontaneity of the sorption process which was endothermic in nature. The results of reusability test of the resins were promising even at the fourth cycle, showcasing the potentials of the new polymers in dyes contaminated water treatment.

Evaluation of structural, optical and physical properties of polyurethane composites doped with metal alkoxides

Abstract In this research, polyurethane (PU)/tetraethyl orthosilicate (TEOS) composite was prepared via one-step polymerization method using different concentrations of TEOS in PU. The structural, optical and physical properties of PU composite were characterized by SEM imaging, FT-IR spectroscopy, water uptake, Raman spectroscopy and optical microscopy imaging of synthesized samples. The SEM results showed that by adding TEOS to the PU, the cell and window size of synthesized samples decreased. This result was also observed in the optical micrographs. The bonding characteristics of PU/TEOS composites were analyzed using Raman and FT-IR spectra. According to the FT-IR spectra, the degree of phase separation (DPS) and hydrogen bonding index, R, in 800 μl TEOS/PU had the highest R and DPS factors. By adding different concentrations of TEOS to PU, the apparent density decreased but the real density increased. The total, open and closed porosity of the synthesized samples were calculated. At low loading of TEOS in PU, the open porosity of the samples increased. The PU/TEOS composites may be promising candidates for absorbing sound.

Transparent and Colorless Polyimides Containing Multiple Trifluoromethyl Groups as Gate Insulators for Flexible Organic Transistors with Superior Electrical Stability

A suitable insulating polymer material that is compatible with the fabrication process of organic transistors and has excellent electrical properties is critically required for the next-generation flexible organic electronics. In this study, using a one-step polymerization method, we synthesized two different solution-processable polyimides (PIs) incorporated with abundant trifluoromethyl groups. Not only were the two resulting PIs-termed 6FDA-6FDAM-PI and 6FDA-TFMB-PI-well soluble in organic solvents, but also they showed transparent and colorless optical properties. The fluorinated PI films showed smooth surface topographies and surface energy values that were appropriate for their use in bottom-gate organic transistors. Organic transistors separately fabricated with 6FDA-6FDAM-PI and 6FDA-TFMB-PI as the gate insulators showed excellent device performance and electrical stability under various testing conditions, especially for pentacene-based devices. The excellent performance of the devices with fluorinated PIs was attributed to the enhanced microstructure of the organic semiconductor and the fluorine-rich characteristic of the underlying gate insulator. Furthermore, organic complementary circuits including the basic logic gates of NOT, NOR, and NAND were demonstrated using these devices.

Ni/Al2O3-La2O3 catalysts synthesized by a one-step polymerization method applied to the dry reforming of methane: effect of precursor structures of nickel, perovskite and spinel

Ni catalysts supported on alumina with various lanthanum contents were prepared by the one-step polymerization method to form catalytic precursors that allow better dispersion of the active nickel metal and improve the Ni-La interaction in catalysts containing Ni, Al and La. The characterization of the materials was performed by XRD analysis, N2 adsorption–desorption, H2-temperature programmed reduction, CO2 and H2-temperature programmed desorption and scanning electron microscopy. The catalytic tests were conducted over a period of 6 h and with a stoichiometric ratio of CH4:CO2 equal to 1. The addition of lanthanum in the catalysts led to the formation of LaNiO3 and LaAlO3 perovskites, with a significant reduction of the specific surface area. The catalysis without the presence of lanthanum (NiAl) presented higher methane conversion during the catalytic test but the NiAlLa0.5 catalyst showed highest catalytic activity when considered the number of active sites exposed for reaction. In addition, it was observed that the formation of LaNiO3 perovskite reduces the sintering of the active phase, increasing the degree of dispersion of the catalysis and provides better Ni-La interaction in dry reforming of methane.