Poly Diallyldimethylammonium Chloride Research Articles

Photoelectrochemical self-powered biosensing cathodic platform by NiO nanosheets/RGO/BiOI heterostructures for detection of glucose

Abstract In this work, a photoelectrochemical (PEC) self-powered sensor based on ITO/NiO/RGO/BiOI electrodes for the detection of glucose was constructed. NiO nanosheets array were grown on an indium tin oxide (ITO) electrode by methods of hydrothermal synthesis, and RGO was successfully loaded by calcination. Then the different layers of BiOI was coated on the above electrode by chemical bath. BiOI has a catalase-like action and produces a special synergistic dual catalytic mechanism with glucose oxidase. PDDA (Poly dimethyl diallyl ammonium chloride) acts as an intermediate linker to connect the modified electrode with glucose oxidase. BiOI has a catalase-like action and produces a special synergistic dual catalytic mechanism with glucose oxidase. Under the optimal experimental conditions, the self-powered PEC sensor has a good photoelectric response in the linear range of 1.0 × 10−7–1.0 × 10−1 mol/L, and the detection limit is 4.7 × 10−8 mol/L. The PEC self-powered sensor has good stability, high sensitivity and excellent reproducibility. On this basis, the sensor has also obtained satisfactory results for ultrasensitive and simple detection of glucose injections.

Hg2+ Optical Fiber Sensor Based on LSPR with PDDA-Templated AuNPs and CS/PAA Bilayers

An optical fiber localized surface plasmon resonance (LSPR) sensor was proposed and experimentally demonstrated to detect Hg2+ ions by functionalizing the optical fiber surface with gold nanoparticles (AuNPs) and chitosan (CS)/poly acrylic acid (PAA) bilayers. A flame-brushing technology was proposed to post-process the polydimethyl diallyl ammonium chloride(PDDA)-templated nanoparticles, avoiding the aggregation of AuNPs and achieving well-dispersed AuNPs arrays. LSPR stimulated by the AuNPs is sensitive to changes in the refractive index induced by Hg2+ ions absorption on the CS/PAA bilayers. Experimental results demonstrated that the LSPR peak wavelength linearly shifts with the concentrations of Hg2+ ions from 1 to 30 μM with a sensitivity of around 0.51 nm/ppm. The sensor also exhibits good specificity and longtime stability.

Magnetic Colloidal Particles in Combinatorial Thin-Film Gradients for Magnetic Resonance Imaging and Hyperthermia

A stable oil-in-water (O/W) magnetic emulsion was prepared by the emulsification of organic ferrofluid in an aqueous media, and its theranostic applications were investigated. The synthesis and characterization of the organic ferrofluid were carried out comprising of superparamagnetic maghemite nanoparticles with oleic acid coating stabilized in octane. Both exhibit spherical morphology with a mean size of 6 nm and 200 nm, respectively, as determined by TEM. Thermogravimetric analysis was carried out to determine the chemical composition of the emulsion. The research work described here is novel and elaborates the fabrication of thin-film gradients with 5, 10, 15, and 20 bilayers by layer-by-layer technique using polydimethyl diallyl ammonium chloride (PDAC) and prepared magnetic colloidal particles. The thin-film gradients were characterized for their roughness, morphology, and wettability. The developed gradient films and colloids were explored in magnetic resonance imaging (MRI) and hyperthermia. T1- and T2-weighted images and their corresponding signal intensities were obtained at 1.5 T. A decreasing trend in signal intensities with an increase in nanoparticle concentration in colloids and along the gradient was observed in T2-weighted images. The hyperthermia capability was also evaluated by measuring temperature rise and calculating specific absorption rates (SAR). The SAR of the colloids at 259 kHz, 327 kHz, and 518 kHz were found to be 156 W/g, 255 W/g, and 336 W/g, respectively. The developed magnetic combinatorial thin-film gradients present a significant potential for the future efficient simultaneous diagnostic and therapeutic bioapplications.

Applying organic polymer flocculants in conditioning and advanced dewatering of landfill sludge as a substitution of ferric trichloride and lime: Mechanism, optimization and pilot-scale study

In this study, poly dimethyl diallyl ammonium chloride (PDADMAC) and polyacrylamide (PAM) were applied to substitute ferric trichloride (FeCl3) and lime conditioning for advanced dewatering of landfill sludge (LS). Four response surface methodology (RSM) models were constructed for FeCl3-lime, FeCl3-PAM, PDADMAC-lime and PDADMAC-PAM, and identical dosages, namely 29.86, 57.91, 5.73 and 2.99 mg/g dry solids (DS) for FeCl3, lime, PDADMAC and PAM, were obtained by solving the system of four RSM equations at water content of 60% to investigate conditioning mechanisms. Compared to FeCl3-lime, PDADMAC-PAM conditioning had strong charge neutralization and bridging performance, and obtained conditioned LS with large flocs size, strong network structure and rapid dewatering rate. By integrating RSM with nonlinear programming for optimization, the total cost of PDADMAC-PAM route was saved by 7.9% and close to FeCl3-lime, and the optimized condition with dosages of 1.93 and 3.47 kg/t DS was further confirmed by pilot-scale experiments. The results indicated that PDADMAC-PAM was a feasible substitute for FeCl3-lime in sludge conditioning, and showed more advantage if dewatered sludge was further treated by incineration.

The fabrication of an electrochemical sensing interface based on Pt nanoparticles/MoS2/graphene nanocomposite for sensitive detection of binaphthol

ABSTRACT In this work, platinum nanoparticles (PtNPs) decorated on poly diallyldimethylammonium chloride (PDDA) functionalised molybdenum disulphide-reduced graphene oxide (MoS2-rGO) was successfully synthesised via hydrothermal process. The morphology and structures of the obtained PtNPs-MoS2-rGO nanocomposite were characterised by UV-vis spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. The nanocomposite combines the large surface area and good electrical properties of MoS2-rGO with the excellent catalytic activity of PtNPs and shows great electrochemical signal enhancement towards binaphthol oxidation. Based on this, an electrochemical sensing interface was constructed for binaphthol determination. Under the optimal conditions, the peak currents display linear response with the concentration of binaphthol over the range from 0.4 to 10 μM and 10 μM to 40 μM. The limit of detection was calculated to be 0.07 μM (S/N = 3). The sensor also has the advantages of simple preparation, good stability and reproducibility. These characteristics make the sensor is promising for the detection of binaphthol and its derivatives in pesticide and pharmaceutical application industries.

Polyelectrolyte-functionalized reduced graphene oxide wrapped helical POMOF nanocomposites for bioenzyme-free colorimetric biosensing

For the sake of effective colorimetric sensing-pattern, a sensitive colorimetric sensor was conceived based on polyoxometalates based metal-organic frameworks (POMOFs) and polydiallyldimethylammonium chloride functionalized reduced graphene oxide (PDDA-rGO) for the first time, in which PDDA as a “glue” molecule turns rGO nanosheets into general platforms for bonding POMOFs nanoparticles. Herein, a new POMOF compound with fascinating helices-on-helices feature, [Ni4(Trz)6(H2O)2][SiW12O40].4H2O (Trz = 1,2,4-triazole) (abbreviated as Ni4SiW12), was synthesized and characterized, then PDDA-rGO sheet as dispersive and conductive material was successfully introduced to Ni4SiW12 fabricating new PDDA-rGO/Ni4SiW12-n nanocomposites, (abbreviated as PMPG-n). The resulting PMPG-n nanocomposites as peroxidase mimetic show excellent catalytic activities under extreme condition (pH value 2.5), attributed to the nature and synergies from POMs, MOFs and PDDA-rGOs. Note that the peroxidase-like activity of PMPG-1 (the mass ratio of Ni4SiW12 to PDDA-rGO is 1:1) exhibits higher sensitivity (1–60 μM), faster response (10 min) and the lowest limit of detection (2.07 μM) among all reported materials to citric acid (CA) to date. This work opens up new application prospects in colorimetric sensing system for food quality control and safety, biotechnology and clinical diagnosis.

Preparation of super high concentration cationic polyacrylamide emulsion and its flocculation with cationic polymers

A super high concentration cationic polyacrylamide emulsion (CPAME‐uhc) was prepared by inverse emulsion polymerization. The influence of its cationic degree and molecular weight on flocculation property was discussed. Then, the chemical structure and micromorphology of the obtained CPAME‐uhc were characterized by Fourier infrared spectrum (FT‐IR), NMR hydrogen spectrum (1H NMR), gel permeation chromatography (GPC), and scanning electron microscope (SEM). Finally, the synergistic flocculation effects of CPAME‐uhc respectively with polydimethyldiallylammonium chloride (PDADMAC), poly methacryloyloxyethyl trimethyl ammonium chloride (PDMC), cationic starch (CS), cationic guar gum (CHPG), cationic chitosan (CTS), and polyamine (PA) on the CPAME‐uhc were investigated. The results showed that the optimum cationic degree and molecular weight of CPAME‐uhc were 25% and 12 million, respectively. FT‐IR and 1H NMR analysis showed that the product was a copolymer of acryloxyethyl trimethyl ammonium chloride and acrylamide. GPC analysis confirmed that the molecular weight distribution of CPAME‐uhc product was very narrow. SEM shows that the latex particles of CPAME‐uhc are regular spheres with a diameter of 200 to 500 nm. When CPAME‐uhc is respectively combined with five cationic polymers in a certain proportion, all of them show good synergistic flocculation to papermaking wastewater. The order of synergistic flocculation effect is: CPAME‐uhc/PDADMAC > CPAME‐uhc/PDMC > CPAME‐uhc/CTS > CPAME‐uhc/CS > CPAME‐uhc/CHPG > CPAME‐uhc/PA. Finally, the mechanism of synergistic flocculation was proposed. This study provides a theoretical and research basis for the preparation of CPAME‐uhc and its application in the treatment of papermaking wastewater.

Thin film composite polyelectrolyte multilayer nanofiltration membrane fabricated using spin assisted layer by layer assembly: Application of solution diffusion film model

Thin Film Composite (TFC) Polyelectrolyte Multilayer (PEM) Nanofiltration (NF) membrane consisting of multilayer of Poly(diallyl dimethyl ammonium chloride) (PDAC) and Poly(sodium 4-styrenesulfonate) (PSS) deposited on polyethersulfone (PES) support was prepared using spin-assisted layer by layer assembly (SA-LbL). This work is an effort to discover new material having better characteristics and performance than commercial polyamide (PA) NF membrane. Two main operating conditions namely temperature and salt concentration were investigated and the effect of both on membrane performance was studied. Solution-diffusion Film Model (SDFM) membrane employing two fitting parameters i.e. membrane salt permeability (PS) and stagnant layer salt permeability PS(d), was used to explain membrane transport across the membrane. The result showed an good agreement between experimental and observed rejection rate suggests PEM membrane behaves similar to typical solution diffusion-type composite membrane and SDFM can be used to predict the membrane performance and behavior.

D-type optical fiber immunoglobulin G sensor based on surface plasmon resonance

In this paper, we report a D-type optical fiber biosensor for human immunoglobulin G (HIgG) detection based on surface plasmon resonance (SPR). The SPR phenomenon was both simulated by COMSOL and observed experimentally. To fabricate the sensor, the cladding of a multimode optical fiber (MMF) was polished using a grinding wheel to obtain a D-type cross-section. Next, a gold film was sputtered on the surface of the MMF. The optimal gold layer thickness and grinding depth were determined through simulations. As per the experimental results, the optimized sensor exhibited high refractive index (RI) sensitivity, which ranged from 1590.9 nm/RIU to 3513.3 nm/RIU for RI values of 1.343 to 1.373. Subsequently, Poly dimethyl diallyl ammonium chloride (PDDA) and Poly(sodium-p-styrenesulfonate) (PSS) were deposited four times in sequence to form polyelectrolyte self-assembled multilayers for the surface functionalization of the fiber. HIgG and goat anti-HIgG (GaHIgG) were chosen as the bioconjugate pair for evaluating the functionality of the fabricated biosensor, and the sensitivity to IgG was determined to be 91 nm/(mg/ml). The specificity of the biosensor was also verified through comparison tests performed using gelatin, horse IgG, and swine IgG. The obtained results confirmed the suitability of the biosensor for use in various biochemical applications.

Natural Flocculant VS Chemical Flocculant Where Is Better To Used In Wastewater Treatment

Nowadays, Coagulation-flocculation process is still common method were used in both large and small scale in wastewater treatment. It’s process an effective method as pretreatment. Flocculant (natural aid) can use many material is an important factors for coagulation-flocculation process. Many materials were used for coagulant-flocculant aid, but typically can be divided into chemical, grafted and or natural aid. Chemical flocculant was made from monomers formed to electrolytes polymers, that is cationic polymers, anionic polymers or non-ionic polymers, such as polyacrylamide have been widely used for decades. Grafted flocculants were synthesized by combining the properties of polymers, both synthetic and natural by ‘connect to’ method, such as Polydiallyldimethylammonium chloride (polyDADMAC or polyDDA). Whereas natural flocculant can be derived from seed of plantago, ovata, moringa, olifiera, etc. Some natural starch can be used as natural aid also. The main advantages of natural flocculant are their renewability, biodegradability, nontoxicity and relative costeffectiveness. but for development in the future constrained by some challanges, Natural flocculant tend to have shorter live which caused by biodegradability of active component, floc will loose. Besides that, chemical flocculants are used because of their easy use. However, in many studies, the usage of chemical flocculant will have an important environmental impact, such as, producing toxic sludge containing metal hydroxides which causes problems with their disposal and increasing metal concentrations (eg aluminum) which can have an impact on the sustainability of human health. This paper will review some chemical flocculant and natural flocculant also tell about environmental affect, both disadvantages and potential which is better used to wastewater treatment.

Anti-Bacterial and Anti-Fouling Capabilities of Poly(3,4-Ethylenedioxythiophene) Derivative Nanohybrid Coatings on SUS316L Stainless Steel by Electrochemical Polymerization.

We have successfully fabricated poly(3,4-ethylenedioxythiophene) (PEDOT) derivative nanohybrid coatings on flexible SUS316L stainless steel by electrochemical polymerization, which can offer anti-fouling and anti-bacterial capabilities. PEDOT derivative nanohybrids were prepared from polystyrene sulfonates (PSS) and graphene oxide (GO) incorporated into a conducting polymer of PEDOT. Additionally, the negative charge of the PEDOT/GO substrate was further modified by poly-diallyldimethylammonium chloride (PDDA) to form a positively charged surface. These PEDOT derivative nanohybrid coatings could provide a straightforward means of controlling the surface energy, roughness, and charges with the addition of various derivatives in the electrochemical polymerization and electrostatically absorbed process. The characteristics of the PEDOT derivative nanohybrid coatings were evaluated by Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle, and surface potential (zeta potential). The results show that PEDOT/PSS and PEDOT/GO nanohybrid coatings exhibit excellent anti-fouling capability. Only 0.1% of bacteria can be adhered on the surface due to the lower surface roughness and negative charge surface by PEDOT/PSS and PEDOT/GO modification. Furthermore, the anti-bacterial capability (7 mm of inhibition zone) was observed after adding PDDA on the PEDOT/GO substrates, suggesting that the positive charge of the PEDOT/GO/PDDA substrate can effectively kill bacteria (Staphylococcus aureus). Given their anti-fouling and anti-bacterial capabilities, PEDOT derivative nanohybrid coatings have the potential to be applied to biomedical devices such as cardiovascular stents and surgical apparatus.

Steering protein and salt ad- and desorption by an electrical switch applied to polymer-coated electrodes

Although solid-phase chromatography is a well-established method for protein separation, chemically intensive and often costly regeneration steps are needed to make reuse of the adsorbent possible. Here, we demonstrate the use of electrochemical principles as sustainable alternative. We make use of spontaneous adsorption of proteins to solid electrodes and reverse this process by applying an electric potential to regenerate the interface. This allows for adsorption of proteins to take place at 0 V difference between the electrodes, due to electrostatic interactions between the protein and the electrode surface. The desorption is then triggered by applying a potential difference (−1.2 V) between the electrodes.It is demonstrated that the incorporation of negatively charged polystyrene sulfonate (PSS) or positively charged polydiallyldimethylammonium chloride (PDMAC) in or on top of the respective activated carbon electrodes increases the amount of exchanged protein from 1 to 10 mg g−1, as compared to simple activated carbon electrodes. Interestingly, salt ad- and desorption occurs in opposite cycles compared to protein ad- and desorption, resulting in simultaneous concentration and desalting of the protein when 0 V is applied. On top of that, we also found that an enrichment in β-lactoglobulin could be achieved starting from whey protein isolate. These results clearly demonstrate that electrochemical technologies can be used not only for protein separation (including removal of salt), but also for protein fractionation, while not requiring solvent use.

Preparation of Functionalized Graphene Multilayer Composite Films Supported Pt Catalyst and its Electro-Oxidation for Methanol

The multilayer composite films consisting of poly (diallyldimethylammonium chloride) functionalized graphene (PDDA-rGO) and phosphomolybdic acid functionalized graphene (PMo12-rGO) were prepared by layer-by-layer self-assembly method. The {PDDA-rGO/PMo12-rGO}n multilayer composite films were used as a support for electro-deposition of Pt particles in situ. Cyclic voltammetry (CV), X-ray photoelectron spectroscopy and scanning electron microscopy were employed for examining the composition, structure, and morphology of the catalyst. Results revealed that the Pt/{PDDA-rGO/PMo12-rGO}n catalyst is successfully prepared and that the multilayer composite films support improves the dispersion of the Pt particles. CV and chronoamperometry were employed to evaluate the electrocatalytic performance for methanol oxidation. Results revealed that the electrocatalytic activity and stability of the Pt/{PDDA-rGO/PMo12-rGO}3 catalyst for methanol oxidation are considerably improved in comparison with that of the Pt/GCE catalyst. The current density for the oxidation of methanol increased from 0.66 mA/cm2 to 1.21 mA/cm2. In addition, the ratio of the forward current density to the backward current density (If/Ib) was 1.92 for Pt/{PDDA-rGO/PMo12-rGO}3 catalyst, corresponding to 1.3 times that of the Pt/GCE catalyst. This result indicated that the multilayer composite films remarkably enhanced the electrocatalytic activity regarding methanol oxidation.

Removal of Acid Blue 92 by Using Amino‐Functionalized Silica‐Pillared Clay as a New Nano‐Adsorbent: Equilibrium, Kinetic and Thermodynamic Parameters

AbstractIn this study, silica‐pillared clay (SPC) and functionalized samples by chitosan (SPC/CTS) and different amounts of poly diallyl dimethylammonium chloride (SPC/PDDA‐10, SPC/PDDA‐20, and SPC/PDDA‐30) have been synthesized and have been employed as some low‐cost and eco‐friendly adsorbents in the adsorptive removal of Acid Blue 92 (AB 92) from contaminated waters. The structural variation of functionalized and unfunctionalized samples confirmed by different techniques such as Scanning electron microscopy (SEM), Energy Dispersive X‐ray spectroscopy (EDX), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR) and N2 adsorption‐ desorption analysis. The SPC/PDDA‐30 was selected for further studies due to its effective adsorption. The optimum values of adsorbent dosage, dye concentration, contact time and pH were found 0.02 g, 120 mg/L, 120 min and 5.0 respectively by applying response surface methodology (RSM). The adsorption equilibrium data were satisfactorily predicted by the Langmuir model and the adsorption process best fitted with a pseudo‐second‐order model. Adsorption thermodynamic analysis indicated the uptake of AB 92 on SPC/PDDA‐30 was exothermic and spontaneous. The high adsorption capacity of the selected nanocomposite could maintain after five successive adsorption‐desorption cycles by using 0.5 M NaOH.

In Situ Sequestration of Perfluoroalkyl Substances Using Polymer-Stabilized Powdered Activated Carbon.

Remediation of groundwater impacted by per- and polyfluoroalkyl substances (PFAS) is particularly challenging due to the resistance of the molecule to oxidation because of the strength of the carbon-fluorine bond and the need to achieve low nanogram per liter drinking water targets. Previous studies have shown that activated carbon is an effective sorbent for removal of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in conventional water treatment systems. The objective of this study was to evaluate the in situ delivery and sorptive capacity of an aqueous suspension containing powdered activated carbon (PAC) stabilized with polydiallyldimethylammonium chloride (polyDADMAC). Batch reactor studies demonstrated substantial adsorption of PFOA and PFOS by polyDADMAC-stabilized PAC, which yielded Freundlich adsorption coefficients of 156 and 629 L/g-n, respectively. In columns packed with 40-50 mesh Ottawa sand, injection of a PAC (1000 mg/L) + polyDADMAC (5000 mg/L) suspension created a sorptive region that increased subsequent PFOA and PFOS retention by 3 orders of magnitude relative to untreated control columns, consistent with the mass of retained PAC. Experiments conducted in a heterogeneous aquifer cell further demonstrated the potential for stabilized-PAC to be an effective in situ treatment option for PFAS-impacted groundwater.

Manipulating the crystalline morphology and facet orientation of copper and copper-palladium nanocatalysts supported on stainless steel mesh with the aid of cationic surfactant to improve the electrochemical reduction of nitrate and N2 selectivity

Surfactants, namely, cetyltrimethylammonium chloride, polydiallyldimethylammonium chloride, and benzethonium chloride were used to control the crystal growth of metallic Cu nanoparticles supported on stainless steel mesh electrodes as to improve the selective electrochemical conversion of NO3− to non-toxic N2. Results showed that the Cu(200)/Cu(111) ratio controlled the selectivity of N2, NO2−, and NH4+. The Kd value increased from 10% to 30% when the Cu(200)/Cu(111) intensity ratio was decreased 60% to 30%, meaning increase Cu(111) increased N2 production. Furthermore, the presence of a second metal, namely, Pd increased the N2 selectivity. The best N2 yield (XN2 = 22%), occurring on monometallic Cu, synthesized with BZT at 1-time CMC was further increased to XN2 = 65% over bimetallic Pd0.27Cu0.73/SS. The selectivity of nitrite (SNO2-) and ammonium (SNH4+) on Cu/SS were 33.1 and 43.5%, respectively, which were decreased to 0.30 and 34.0%, respectively, on bimetallic Pd0.27Cu0.73/SS.

Inkjet jettability and physical characterization of water–ethanol solutions of low molecular weight sodium polyacrylate and poly-diallyl dimethyl ammonium chloride (polyDADMAC)

Polyelectrolytes are water-soluble polymers having repeat units carrying electrolyte groups. As polyionic molecules having like charge units, they are self-repelling with a rod-like conformation in solution. Inkjet applications of polyelectrolytes include particle dispersing, surface modification, and multilayer structures. This work investigates the physical properties of low molecular weight sodium polyacrylate (NaPA) and poly-diallyl dimethyl ammonium chloride (polyDADMAC) polyelectrolyte solutions in the water–ethanol mixture in relation to their behavior in inkjet deposition. In rotational rheometry measurements, the solutions are found to behave in a Newtonian fashion once the effects of experimental artifacts are taken into account. The range of NaPA concentrations that could be studied was limited to 1 wt./wt. % by the poor solubility of NaPA in the presence of ethanol, and at these concentrations, the addition of NaPA to the solvent did not have a significant effect on the jetting behavior. PolyDADMAC had good solubility, and concentrations up to 10 wt./wt. % were studied and jetted successfully. While an increase in polyelectrolyte concentration resulted in a slow increase in ink viscosity, this was not found to have a significant effect on the required jetting voltage or maximum stable jetting frequency, though drop detachment and satellite droplet formation times were found to increase. As a practical limitation of polyDADMAC inks, solvent evaporation was found to lead to idle nozzles becoming non-jetting, with the allowed idle time decreasing rapidly as ink polyDADMAC concentration increased. This non-jetting behavior is likely due to residence time at the nozzle exit leading to the local surface tension and/or viscosity increase, differing from the bulk ink properties.

Surface Engineering of Carbon Nanotubes with Inorganic-Organic Materials for Electrochemical Capacitors.

Composite electrodes comprised of inorganic-organic molecular materials are of great interest in applications such as electrochemical capacitors (ECs). ECs store and release charge via double layer capacitance (EDLC) or pseudocapacitance. The carbon materials used for EDLC has low capacitance, while pseudocapacitive materials such as redox active polymers or metal oxides have long term stability issues. Therefore, anchoring inorganic-organic materials on a carbon substrate can leverage the advantages of both EDLC and pseudocapacitance. Composite electrodes of kegging type polyoxometalates (POM) deposited on polydiallyldimethylammonium chloride (PDDA) via the layer-by-layer assembly has been well established and has shown great promise [1-3] . The issues are the limited operation window and the inert PDDA layer. Suitable alternatives that can complement the redox activity of POMs and enlarge the operating potential window are redox active polymers [4].The objectives of this work are to: 1) develop and optimize an electroactive inorganic-organic composite electrode based on a carbon nanotube (CNT) substrate modified with polyluminol (CpLum) and H5GeMo11VO40.24H2O (GeMo11V); 2) study the electrochemical behavior of the composite electrode with and without PDDA for electrochemical capacitors; and 3) investigate the interactions between each layer.GeMo11V was first deposited onto CNT using PDDA as an anchor. The vanadium atom in the kegging structure provided an additional electrochemical redox peak with improved capacitive behavior on the cyclic voltammogram (CV) as seen in figure 1. First, CpLum, and GeMo11V were applied on CNT (CNT-CpLum-GeMo11V), then co-deposited with PDDA (CNT-CpLum-PDDA-GeMo11V). For both composite electrodes, CpLum and GeMo11V contributed to the redox activity leading to a wider potential window. The CV of CNT-CpLum-GeMo11V showed more reversible redox peaks with a slightly reduced GeMo11V contribution compared to CNT-CpLum-PDDA-GeMo11V that had a smoother CV shape. The decrease in GeMo11V contribution was attributed to the smaller amount of positive charge within the CpLum chain needed to anchor the GeMo11V. Each layer had a distinct role in the inorganic-organic composite electrode. The CpLum polymer added additional redox activity in the higher potential range, while PDDA attracted and held the GeMo11V, which provided redox activity in the lower potential range. All three layers had a synergistic interaction and provided enhanced charge storage properties with good rate capability and cycling stability.REFERENCES 1. M. Genovese, Y. W. Foong and K. Lian, Electrochimica Acta, 199, 261 (2016).2. M. Genovese and K. Lian, Current Opinion in Solid State and Materials Science, 19, 126 (2015).3. M. Genovese, Y. W. Foong and K. Lian, Journal of The Electrochemical Society, 162, A5041 (2015).4. N. Casado, G. Hernández, H. Sardon and D. Mecerreyes, Progress in Polymer Science, 52, 107 (2016). Figure 1

Preparation and inhibition mechanism of bis-quaternary ammonium salt as shale inhibitor used in shale hydrocarbon production

Countries around the world have shown great enthusiasm for shale gas and shale oil. Their production accounts for an increasing proportion in the output of unconventional oil and gas resources in the past several years. The clay minerals with large content in shale will be hydrated and swelled when encountering the external working fluid, thus causing water-sensitivity damage, which is the main problem that the efficient development of shale hydrocarbon resources reservoirs faces. Polyether amine is a kind of newly developed clay stabilizer in recent years, which exhibiting good shale inhibition performance. However, it was found in experiments that changing the pH value of polyether amine solution can strengthen or weaken its shale inhibition property. In response to this finding, the bis-quaternary ammonium salt was prepared with polyether amine as raw material. Its anti-swelling rate on sodium bentonite was 95.2%, which was 24.8%, 7.7%, 12.5% and 17.8% higher than that of the commonly used clay stabilizers such as tetramethyl ammonium chloride, poly epichlorohydrin-dimethylamine, poly dimethyl diallyl ammonium chloride, and polyether amine respectively. And bis-quaternary ammonium salt can effectively inhibit the hydration, swelling and dispersion of shale samples in water. The inhibition mechanism was studied systematically from the aspects of adsorption characteristics of bis-quaternary ammonium salt on clay surface, effect of bis-quaternary ammonium salt on clay hydration, and effect of bis-quaternary ammonium salt on clay swelling. This study provides an excellent shale inhibitor to reduce the permeability damage for efficient and sustainable development of shale gas and shale oil.

Functional oil-repellent photothermal materials based on nickel foam for efficient solar steam generation

The production of fresh water by means of solar steam generation has emerged as one of frontier technologies for addressing the global water shortage issue. Here, we report the preparation of new photothermal materials by chemical modification of nickel foam with sulfur via a simple hydrothermal method for solar steam generation. The generation of nano nickel wire on the surface of skeleton of nickel foam by sulfur treatment could construct a much more dense network with hierarchical porous structure and hydrophilicity, which significantly enhance their light absorption (average 40–50% for untreated nickel foam while 91% for sulfur treated nickel foam (named as S–Ni foam) as well as water transportation. In the way, the as-prepared S–Ni foam possesses a high energy conversion efficiency of 83.6% under 1 kW m−2 irradiation. In view of most of reported photothermal materials which suffer the drawback of lose effectiveness in oily water, the S–Ni foam was further chemically modified with an anionic coordination between sodium perfluorooctanoate (PFO) and poly diallyl dimethyl ammonium (PDDA) chloride to achieve a strong hydrophilic-oleophobic wettability (named as OR-S-Ni foam). Such unique wettability endows the as-resulted OR-S-Ni foam excellent oil-repellent performance, making it possible solar vaporization even in water containing oils or organics contaminates, which should be of significantly technological significance for practical solar steam generation by largely extends its applications range.