Diallydimethylammonium Chloride Research Articles

Design and Synthesis Silica-Polyelectrolyte-Iron Oxide Nanocomposite with Magnetic-Catalytic Bifunctionalities for Dye Removal

Incorporation of iron oxide nanoparticles into Poly(diallydimethylammonium chloride) coated silica colloids is developed to produce novel nanocomposite. The structure is synthesized via layer-by-layer assembly with the entire process driven by electrostatic interaction. Dynamic light scattering and zeta potential measurements are employed to monitor the evolution of the nanocomposite from its constituent materials to full development of final structure. Morphology of the as-synthesized nanocomposite is observed by transmission electron microscopy. The magnetic responsiveness under low magnetic field gradient enables the aforementioned nanocomposite to be recovered for recycle purpose. The engineering application of this material is tested by taking Methylene Blue and Remazol Brilliant Blue R dyes as model system. The study reveals the efficiency and activity of the nanocomposite for dye removal during four consecutive runs.

Flocculation of kaolin and lignin by bovine blood and hemoglobin

BACKGROUND The kaolin flocculant activities of bovine blood (BB) and hemoglobin (HEM) at different salt and pH values were determined. Lower limit concentration (LLC), window of application (WA), and degrees of clarification (DC) values for BB and HEM were determined and compared with those of the synthetic polymeric flocculants poly(diallydimethylammonium chloride) (PDADMAC), cationic polyacrylamide (PAM), and anionic PAM. BB flocculation of lignin, a bioproduct of biomass conversion to bioethanol, was demonstrated. RESULTS Flocculation of kaolin by BB and HEM increased at acidic pH and in the presence of NaCl. LLC values of HEM and BB were similar to LLC values of cationic and anionic PAM. LLC values of HEM and BB were 18–20-fold higher than that of PDDMAC. WA values of BB and HEM were similar to those of PDADMAC, cationic PAM, and anionic PAM. For lignin flocculation, the ratio of LLC for BB/PDADMAC was 20–38, but the ratio of WA for BB/PDADMAC was > 3.6. For kaolin and lignin flocculation, DC values were similar for all flocculants. CONCLUSIONS The renewable flocculants BB and HEM rapidly settle kaolin and lignin suspensions; BB and HEM could be used in the process to separate lignin from other biomass components. Published 2014. This article is a U.S. Government work and is in the public domain in the USA

DNA-length-dependent fluorescent sensing based on energy transfer in self-assembled multilayers

In this paper, a novel DNA-length-dependent fluorescent sensor was constructed based on the fluorescence resonance energy transfer. In the self-assembled multilayers (Quartz/GO/PDDA/Tx-DNA/PDDA/ZnO@CdS), ZnO@CdS and graphene oxide(GO) were employed as an energy donor and an energy acceptor, respectively. Single-stranded Tx-DNA (x represents different chain length of DNA) and poly(diallydimethylammonium) chloride (PDDA) were used as a linker. In the presence of complementary Px-DNA, the formation of double-stranded DNA leads to a change in chain length and achieves the purpose of changing the distance between ZnO@CdS and GO. Thereby, it enhances the efficiency of energy transfer between ZnO@CdS and GO resulting in the quench of fluorescence of ZnO@CdS, and thus different length DNA sequence was detected.

Distance-Dependent Surface Plasmon Resonance Coupling Between a Gold Grating Surface and Silver Nanoparticles

In this study, we achieved an enhancement of the transmission surface plasmon resonance (T-SPR) intensity by depositing silver nanoparticles (AgNPs) onto a gold grating substrate. The T-SPR spectrum of the gold grating substrate with AgNPs showed a strong and narrow SPR peak located between 650 and 800 nm; the maximum SPR excitation was observed at a 35° angle of incidence. We controlled the distance between the gold grating surface and the AgNPs by using layer-by-layer (LbL) ultrathin films of poly(diallydimethylammonium chloride) (PDADMAC) and poly(sodium 4-styrenesulfonate) (PSS) to study the distance dependence of the coupling effect between the AgNPs and the gold grating substrate. The distance-dependent T-SPR response of peak position and intensity showed distinctive changes when the intermediate layer was 10 bilayers (∼17 nm) thick. The strongest coupling surface plasmon excitation between the AgNPs and the gold grating substrate was obtained at this layer spacing. Furthermore, we explored the potential of the developed system as a switchable pH sensor. The T-SPR spectrum sensitively changed as the pH switched from acidic (pH 2) to alkaline (pH 12) conditions by the swelling/shrinking of the poly(allylamine hydrochloride) (PAH)/PSS LbL film, respectively, which was deposited between the AgNPs and the gold grating.

Graphene and Polyoxometalate Synergistically Enhance Electro-Catalysis of Pd toward Formic Acid Electro-Oxidation

A novel catalyst support constructed from poly (diallydimethylammonium chloride) functionalized graphene (PDDA-GN) and H3PMo12O40 (PMo12) was prepared by layer by layer (LBL) electrostatic assembly and were used for electro-deposition of Pd particles in situ. The Pd/{PDDA-GNs/PMo12}n composite films were characterized by Raman, XPS, EDS, XRD, AFM and TEM. The composite films presented good electrocatalytic activity, better electrochemical stability and improved tolerance of CO in cyclic voltammetry, chronoamperometry and CO-stripping voltammetry tests. Especially, the catalytic activity of the as prepared composite toward formic acid electro-oxidation is 4.1 times of the commercial Pd/C catalyst. It indicates that PDDA-GNs preserve superior electric conductivity of graphene sheets in the composite films, and the introduction of electroactive PMo12 into the composite films contributes to convert intermediate species CO into CO2. The synergistic effects of PDDA-GNs and PMo12 remarkably enhance the electrocatalytic activity and stability of nano-Pd regarding formic acid oxidation.

Layer-by-layer deposition of cationic and anionic carbon nanotubes into thin films with improved electrical properties

In this study, the electrical properties of carbon nanotubes (CNTs) assembled into different architectures using the layer-by-layer technique have been investigated. The CNTs were modified with either anionic water-soluble polyaniline blend poly(sodium 4-styrenesulfonate) (PANI-PSS) or cationic poly(diallydimethyl ammonium chloride) (PDADMAC) to form negatively charged CNT− and positively charged CNT+. PANI-PSS was synthesized by interfacial polymerization of aniline using PSS as template. The first of the three architectures studied was assembled by the LbL deposition of anionic CNT− and cationic CNT+ while the two others were prepared by the deposition of only 1 type of CNTs (CNT+ or CNT−) with an oppositely charged polyelectrolyte to form PDADMAC/CNT− and PANI-PSS/CNT+. The thickness and surface roughness of the three different films were characterized by atomic force microscopy (AFM) while the electrical and optical properties were measured using a four points probe setup and a UV–vis spectrophotometer, respectively. The dispersion of the CNTs using PANI-PSS as capping agent was the least efficient when compared to the PDADMAC leading to a lower adsorption on a charged substrate. Interestingly, the layer-by-layer deposition of the CNT−/CNT+ films had a slower growth but displayed a superior electrical conductivity when compared to the other two architectures.

Facilely prepared composites of polyelectrolytes and graphene as the sensing materials for the detection of very low humidity

Two polyelectrolytes, i.e., cationic poly(diallydimethylammonium chloride) (PDDA) and anionic sodium poly(4-styrenesulfonate) (PSSNa), were separately mixed with graphene oxide (GO) and hydrazine in solution, and heat-treated to result in composites of PDDA/graphene (GN) and PSSNa/GN, respectively. The composites were characterized by scanning electron microscopy, transmittance electron microscopy and Raman spectroscopy. Impedance-type humidity sensors were constructed by depositing the composite films onto interdigitated gold electrodes via dip-coating. The electrical response of the composite humidity sensors toward relative humidity (RH) was investigated at room temperature. It was found that the composites with higher content of GN exhibited lower impedance at low humidity levels. Both composite sensors could detect very low humidity (down to 0.2%RH), and showed good response magnitude in the low humidity range (relative impedance change of 300% and 1000% from 0.2 to 30%RH for PSSNa/GN and PDDA/GN, respectively). Moreover, the composites exhibited slight hysteresis similar to that of the polyelectrolytes alone, while their response time for desorption was even reduced. The sensing mechanism of the composites was explored by complex impedance spectra analysis, and the good sensing behavior at low humidity was proposed to the special electrical property and unique two-dimensional nanosheet structure of GN.

Distribution of label free cationic polymer-coated gold nanorods in live macrophage cells reveals formation of groups of intracellular SERS signals of probe nanoparticles

Gold nanorods coated with poly(diallydimethylammonium chloride) (PDAC-GNRs) were used to observe the distribution of surface-enhanced Raman signals in live cells and generate distinct groups of surface-enhanced Raman scattering (SERS) spectra in different regions of the cells. Spectra with unique features were clustered into sets of molecules in live murine macrophage cells (Raw 264.7). The distribution of biological substances detected by SERS signals of PDAC-GNRs is also discussed.

Charged microcapsules for controlled release of hydrophobic actives Part II: Surface modification by LbL adsorption and lipid bilayer formation on properly anchored dispersant layers

Charge microcapsules with a dodecane core and a poly(methyl methacrylate) (PMMA) shell have been prepared via the internal phase separation method using ionic dispersants. The microcapsules have subsequently been surface modified with polyelectrolyte multilayers and lipid bilayers. Two types of ionic dispersant systems have been investigated: a small set of ionic amphiphilic block copolymers of poly(methyl methacrylate)-block-poly(sodium (meth)acrylate) type and an oil-soluble anionic surfactant, sodium 1,5-dioxo-1,5-bis(3,5,5-trimethylhexyloxy)-3-((3,5,5trimethylhexyloxy)carbonyl)pentane-2-sulfonate, in combination with a water-soluble polycation, poly(diallyldimethylammonium chloride). The Layer-by-Layer adsorption of the polyelectrolyte pair poly(diallydimethylammonium chloride) (350,000g/mol) and poly(sodium methacrylate) (15,000g/mol) was successfully made on both microcapsule systems with the formation of very thin multilayers as indicated with quartz crystal microbalance with dissipation monitoring (QCM-D) measurements on model surfaces. Formation of a lipid bilayer on the surface of the microcapsules from liposomes with a charge opposite that of the capsule surface was also proven to be successful as indicated by the ζ-potential of the microcapsules, the characteristic frequency shift as measured with QCM-D and fluorescence recovery after photobleaching (FRAP) on model systems. However, the proper anchorage of the dispersants in the underlying PMMA surface was key for the successful surface modification.

Flammability and combustion properties of ammonium polyphosphate-/poly(acrylic acid)- based layer by layer architectures deposited on cotton, polyester and their blends

Layer by layer architectures consisting of four layer repetitive unit (QL) based on poly(diallydimethylammonium chloride)/poly(acrylic acid)/poly(diallydimethylammonium chloride)/ammonium polyphosphate have been deposited on cotton, polyester and their blends in order to promote the formation of an aromatic and stable carbonaceous structure (char) during combustion. The LbL-treated fabrics have been subjected to flammability (reaction to flame application) and combustion (reaction to different external heat fluxes) tests. The coatings were able to remarkably enhance the char formation of each substrate just after 1QL deposition; furthermore, 5 and 10QL assemblies have favoured the formation of intumescent-like structures with further improvement of the final residue. As a consequence, the treated fabrics have shown a strong reduction of the flammability (afterglow and incandescent melt dripping suppression) and combustion (reduced heat released). Infrared spectroscopy has pointed out the aromatic nature of the residues left after the combustion.

Homogenous polyelectrolyte complex membranes incorporated with strong ion-pairs with high pervaporation performance for dehydration of ethanol

Solution-processable polyelectrolyte complexes (PECs) incorporated with both sulfate (OSO3) groups and carboxylic acid groups (COOH) were prepared from sulfated sodium carboxymethyl cellulose (SCMC) and poly(diallydimethylammonium chloride) (PDDA). Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were utilized to characterize the chemical structures of SCMC and the compositions of SCMC/PDDA PECs. Membranes were made from PECs (SPECMs), and their surface properties were studied by field emission scanning electron microscopy and contact angle characterizations. Moreover, SPECMs were subjected to pervaporation dehydration of aqueous ethanol solution. Effects of SPECMs’ chemical compositions and operation conditions on pervaporation performance were studied and discussed in terms of membrane structures. It was found that OSO3 groups were incorporated into SPECMs in the form of sulfate–amine ion-pairs, and they improved both the selectivity and flux in the dehydration of aqueous ethanol solution. For instance, the flux and water content in permeate for SPECM-0.34 in dehydration of 10wt% water–ethanol mixture at 70°C were 1760gm−2h−1 and 98.7wt%, respectively, both of which were much higher than those for pristine PEC membranes with no sulfate groups. Moreover, the high separation performance of SPECMs was stable and both the tensile strength and elongation at break increased with increasing strong ion-pairs content. For instance, the SPECM-0.34 tensile strength and elongation at break were 64.5MPa and 9.33%.

Layer-by-layer assembly of polyelectrolyte and graphene oxide for open-tubular capillary electrochromatography

In this paper, open-tubular capillary column coated with graphene oxide (GO) was prepared through ionic adsorption of negatively charged GO nanosheets onto the capillary wall pre-modified with positively charged poly(diallydimethylammonium chloride) (PDDA). Thus prepared coating was very stable and could endure over 200 separations. The electroosmotic flow (EOF) characteristics of bare fused silica capillary column, PDDA coated column, and GO-PDDA coated column (GO-PDDA@column) were investigated by varying the percentage of methanol in buffer and the buffer pH value. The run-to-run, day-to-day, and column-to-column reproducibilities of EOF on GO-PDDA@column were satisfying with relative standard deviation values of less than 2% in all cases. The stationary phase displays a characteristic reversed-phase behavior. The GO-PDDA@column was also used to separate proteins in egg white. Both basic and acidic proteins were separated in a single run.

Application of graphene as the stationary phase for open-tubular capillary electrochromatography

We reported the application of graphene as a novel stationary phase in open-tubular capillary electrochromatography (OTCEC). The OT column was easily fabricated by electrostatic assembly of poly(diallydimethylammonium chloride) followed by self-adsorption of negatively charged graphene. The chromatographic properties of graphene-coated OT column were investigated by separation of nitroaniline isomers through variation of the buffer pH, sodium dodecyl sulfate concentration and separation voltage. The results demonstrate the application of graphene in OTCEC greatly improves the separation by largely enhancing the surface area thus increasing stationary/mobile phase interaction. The proposed OT column exhibits good repeatability with run-to-run RSD of retention time as low as 1.5% (n=5), and excellent stability for at least two-week usage with total ∼200runs. The method was successfully applied for analysis of nitroaniline isomers in hair dye samples.

Synthesis of graphene nanosheets with incorporated silver nanoparticles for enzymeless hydrogen peroxide detection

Herein, we report on the production of poly(diallydimethylammonium chloride) (PDDA) functionalized reduced graphene oxide (PDDA-rGO) with the use of PDDA as a reducing and stabilizing agent. Atomic force microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the resulting PDDA-rGO nanosheets. The PDDA-rGO nanosheets could be modified with Ag nanoparticles (AgNPs) by direct adsorption of preformed, negatively charged AgNPs. It was found that the AgNPs were distributed uniformly on the PDDA-rGO nanosheets and the obtained PDDA-rGO/AgNPs nanocomposites exhibited prominent electrocatalytic activity for the detection of hydrogen peroxide (H2O2) with a wide linear range from 100 μM to 41 mM (r = 0.997) and a rapid response upon the addition of H2O2. The detection limit was estimated to be 35 μM. Furthermore, the fabricated nonenzymatic H2O2 electrochemical sensor demonstrated excellent stability and reproducibility.

Biocompatible Multishell Architecture for Iron Oxide Nanoparticles

The coating of super-paramagnetic iron oxide nanoparticles (SPIONs) with multiple shells is demonstrated by building a layer assembled from carboxymethyldextran and poly(diallydimethylammonium chloride). Three shells are produced stepwise around aggregates of SPIONs by the formation of a polyelectrolyte complex. A growing particle size from 96 to 327 nm and a zeta potential in the range of +39 to -51 mV are measured. Microscopic techniques such as TEM, SEM, and AFM exemplify the core-shell structures. Magnetic force microscopy and vibrating sample magnetometer measurements confirm the architecture of the multishell particles. Cell culture experiments show that even nanoparticles with three shells are still taken up by cells.

A novel composite film derived from cysteic acid and PDDA-functionalized graphene: Enhanced sensing material for electrochemical determination of metronidazole

A novel composite film derived from cysteic acid and poly(diallydimethylammonium chloride)-functionalized graphene (PDDA-GN) was employed as an enhanced electrode material for ultrasensitive determination of metronidazole. The cysteic acid/PDDA-GN composite film was prepared by the electrochemical grafting of cysteic acid onto the PDDA-GN coated glassy carbon electrode (GCE). The cyclic voltammetry investigations reveal that the peak current of metronidazole reduction at the cysteic acid/PDDA-GN/GCE was remarkably enhanced compared to the bare GCE, the cysteic acid/GCE and the PDDA-GN/GCE. This result implies the synergistic electrocatalytic effect of cysteic acid and PDDA-GN. The fabricated sensor shows linear response to metronidazole in the ranges of 10nM–1μM and 70μM–800μM, with a detection limit of 2.3nM (S/N=3). The heterogeneous electron transfer rate constant and the diffusion coefficient of metronidazole were further evaluated by rotating disk electrode experiments. Moreover, we applied the present method to the determination of metronidazole in urine and lake water with satisfactory results.

Human serum albumin-coated gold nanoparticles for selective extraction of lysozyme from real-world samples prior to capillary electrophoresis

This study describes the use of human serum albumin (HSA)-modified gold nanoparticles (HSA-AuNPs) for the selective extraction and enrichment of high-pI protein, lysozyme (Lyz) prior to analysis by capillary electrophoresis (CE) with UV detection. HSA-AuNPs are capable of extracting Lyz from a complex matrix because a HSA capping layer not only stabilizes gold nanoparticles in a high-salt environment but also exhibits strong electrostatic attraction with Lyz under neutral pH condition. Efficient separation of Lyz and other high-pI proteins has been successfully achieved by the filling of cationic polyelectrolyte, poly(diallydimethylammonium chloride) (PDDAC), to the background electrolyte. After capturing Lyz with HSA-AuNPs, PDDAC-filled CE can be directly used for the analysis of the extracted Lyz without the addition of the releasing agent into the extractor. The extraction efficiency relied on the pH of the solution and the concentration of HSA-AuNPs. Under optimal extraction conditions, the limit of detection at a signal-to-noise ratio of 3 for Lyz was down to 8nM. The combination of HSA-AuNP extraction and PDDAC-filled CE has been applied the analyses of Lyz in hen egg white, human milk, and human tear. Also, this NP-based extraction can be coupled to matrix-assisted desorption/ionization time-of-flight mass spectrometry and sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Interfacial polymerization of polyaniline and its layer‐by‐layer assembly into polyelectrolytes multilayer thin‐films

AbstractThe layer‐by‐layer (LbL) self assembly deposition technique was used to prepare multilayer thin films of anionic polyaniline‐blend‐poly(sodium 4‐styrenesulfonate) (PANI‐PSS) and cationic poly(diallydimethylammonium chloride) (PDADMAC). Anionic polyaniline was prepared by the interfacial polymerization of aniline monomer in the presence of PSS which acted as template to provide water solubility. The PSS to PANI concentration ratios used in the synthesis step was found to have a major effect on the final PANI‐PSS synthesis, its self assembly and the electrical properties of the prepared films. The optical and electrical properties of the films were measured by ultraviolet‐visible spectroscopy (UV‐Vis) and a 4‐point probe setup, respectively while the thickness of the films was measured by atomic force microscopy (AFM). Results showed that the optimum condition for the film growth and optimal conductivity were obtained with different synthesis conditions. These results suggest that the PSS concentration used for interfacial synthesis of PANI must be finely tuned depending on the type of application aimed by the user. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Influence of ammonium polyphosphate-/poly(acrylic acid)-based layer by layer architectures on the char formation in cotton, polyester and their blends

Ammonium polyphosphate and poly(acrylic acid) have been chosen to build a complex, four-layered (or quadlayered) hybrid organic-inorganic architecture exploiting the Layer by Layer assembly, in order to promote the formation of an aromatic and stable carbonaceous structure (char), able to thermally protect cotton, polyester and their blends. To this aim, a different number of quadlayers (namely, 1, 5 and 10) consisting of poly(diallydimethylammonium chloride)/poly(acrylic acid)/poly(diallydimethylammonium chloride)/ammonium polyphosphate have been deposited on the chosen fabrics and investigated. Thermogravimetric analysis coupled to isothermal tests performed in a gravity convection oven at fixed temperatures has shown that the presence of such architectures is able to enhance the char formation in a remarkable way. Furthermore, infrared spectroscopy has pointed out the aromatic nature of the residues left by the treated fabrics upon heating at high temperatures, regardless of the quadlayer number and the fabric type.

Electrocatalytic Reduction of H<SUB>2</SUB>O<SUB>2</SUB> on Thiolate Graphene Oxide Covalently to Bonded Palladium Nanoparticles

The electrocatalytic reduction of hydrogen peroxide on thioalted graphene oxide (t-GO) covalent bonded to palladium nanoparticles was used as the basis of an H2O2 biosensor. Poly (diallydimethylammonium chloride)-coated t-GO-Pd on glassy carbon electrodes was easily and quickly prepared and gave sensitive measurements of H2O2 concentration. The Pd nanoparticles covalently bonded to the thiolated graphene oxide were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy. Comparable results for H2O2 determination were obtained from cyclic voltammetric and amperometric measurements. The proposed H2O2 biosensor exhibited a wide linear range of 10 microM to 10 mM, and a low detection limit of 0.22 microM (S/N = 3), at an applied potential of -0.1 V by the amperometric method.