Diallyldimethylammonium Chloride Research Articles

Diallyl dimethyl ammonium chloride (DADMAC) and acrylic acid (AAc) embedded nonwoven irradiated polyethylene fabric as efficient adsorbent to separate U(VI) from aqueous solution

Selective isolation of uranium (VI) from wastewater is now a subject of concern due to its damaging effect on living beings. In this study, the pre-irradiation technique was used to prepare grafted polymeric adsorbent by diallyl dimethyl ammonium chloride (DADMAC) and acrylic acid (AAc) onto nonwoven polyethylene fabric (PE) and the grafted adsorbent was applied for uranium (VI) adsorption from aqueous solution by batch method. After irradiation of the non-woven polyethylene fabrics with 50 kGy radiation dose, the grafting reaction was carried out at 80 ºC with a monomer solution consisting of 20 g DADMAC and 20 g AAc to 110 mL deionized water. The prepared adsorbent was characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), and Thermo-gravimetric Analysis (TGA). After treatment with NaOH solution, the adsorption study was analyzed by pH, initial metal ion concentrations, contact time, and temperature on the adsorption of U(VI). The highest graft yield was achieved at 598%. The maximum adsorption capacity achieved at 160 mg/g was found by treating with 0.1M NaOH for 4 minutes with an initial concentration of 1000 ppm, pH 3.3, and a contact time of 48 hours at room temperature (25 °C). Kinetic adsorption data fitted better with the pseudo-second-order equation and a good correlation of experimental data with the Langmuir isotherm model suggested monolayer adsorption. Langmuir equation showed that the maximum adsorption capacity for U(VI) was 333.333 mg/g. The study depicted good results on the desorption and reuse of the adsorbent.

Formation, toxicity, and mechanisms of halonitromethanes from poly(diallyl dimethyl ammonium chloride) during UV/monochloramine disinfection in the absence and presence of bromide ion

Bromide ion (Br−) is known as a prevalent component in water environments, which exhibits significant impacts on halonitromethanes (HNMs) formation. This study was performed to explore and compare the formation, toxicity, and mechanisms of HNMs from poly(diallyl dimethyl ammonium chloride) (PDDACl) in the absence and presence of Br− in the UV/monochloramine (UV/NH2Cl) disinfection process. The results showed that chlorinated HNMs were found in the absence of Br−, while brominated (chlorinated) HNMs and brominated HNMs were found in the presence of Br−. Furthermore, the peaks of total HNMs were promoted by 2.0 and 2.4 times, respectively when 1.0 and 2.0 mg L−1 Br− were added. Also, the peaks of total HNMs were enhanced with the increase of the NH2Cl dosage, which were reduced with the increase of pH. It should be noted that Br− induced higher toxicity of HNMs, and the cytotoxicity and genotoxicity of HNMs with the addition of 2.0 mg L−1 Br− were 78.0 and 3.7 times those without the addition of Br−, respectively. Meanwhile, both the reaction mechanisms of HNMs produced from PDDACl were speculated in the absence and presence of Br−. Finally, different HNMs species and yields were discovered in these two real water samples compared to those in simulated waters. These findings of this work will be conducive to understanding the significance of Br− affecting HNMs formation and toxicity in the disinfection process.

Advanced Oxidation Processes Coupled to Nanofiltration Membranes with Catalytic Fe0 Nanoparticles in Symmetric and Asymmetric Polyelectrolyte Multilayers.

The in situ synthesis of Fe0 particles using poly-(acrylic acid) (PAA) is an effective tool for fabricating catalytic membranes relevant to advanced oxidation processes (AOPs). Through their synthesis in polyelectrolyte multilayer-based nanofiltration membranes, it becomes possible to reject and degrade organic micropollutants simultaneously. In this work, we compare two approaches, where Fe0 nanoparticles are synthesized in or on symmetric multilayers and asymmetric multilayers. For the membrane with symmetric multilayers (4.0 bilayers of poly (diallyldimethylammonium chloride) (PDADMAC)/PAA), the in situ synthesized Fe0 increased its permeability from 1.77 L/m2/h/bar to 17.67 L/m2/h/bar when three Fe2+ binding/reducing cycles were conducted. Likely, the low chemical stability of this polyelectrolyte multilayer allows it to become damaged through the relatively harsh synthesis. However, when the in situ synthesis of Fe0 was performed on top of asymmetric multilayers, which consist of 7.0 bilayers of the very chemically stable combination of PDADMAC and poly(styrene sulfonate) (PSS), coated with PDADMAC/PAA multilayers, the negative effect of the Fe0 in situ synthesized can be mitigated, and the permeability only increased from 1.96 L/m2/h/bar to 2.38 L/m2/h/bar with three Fe2+ binding/reducing cycles. The obtained membranes with asymmetric polyelectrolyte multilayers exhibited an excellent naproxen treatment efficiency, with over 80% naproxen rejection on the permeate side and 25% naproxen removal on the feed solution side after 1 h. This work demonstrates the potential of especially asymmetric polyelectrolyte multilayers to be effectively combined with AOPs for the treatment of micropollutants (MPs).

Mixtures of Cationic Linear Polymer and Anionic Polymeric Microspheres for Stabilization of Sand: Physicochemical, Structural and Mechanical Study

Aqueous formulations based on anionic butadiene-styrene microspheres (BSMs) and cationic poly(diallyldimethylammonium chloride) (PDADMAC) with the weight PDADMAC fraction from 0 to 1 were studied as the stabilizers of loose sandy soils. In general, these systems were shown to be represented as the mixtures of microspheres saturated with PDADMAC and unbound polycation. Mechanical testing of BSMs–PDADMAC films evidenced that with increasing weight PDADMAC fraction, a 20-fold growth in elastic modulus, 2-fold growth in strength and 2-fold decrease in ultimate strain of the material were observed. Treatment of the sand with the above formulations resulted in formation of a protective porous polymer-sand surface crust with the strength from 0.8 to 45.0 MPa. “Elasticity–rigidity” balance and water resistance of the crusts were controlled by weight fraction of polycation in the mixed formulation. Stable water-resistant polymer-sand crusts were shown to be prepared using formulations with the weight PDADMAC fraction from 0 to 0.2. The results indicated a great potential of the polymer-colloid formulations for the fabrication of structured sand coatings with controlled properties.

Determination of trypsin using protamine mediated fluorescent enhancement of DNA templated Au nanoclusters

Afluorescent method is describedfor trypsin determination through the strong electrostatic interactions between cationic polyelectrolytes and single-stranded DNA (ssDNA) templated Au nanoclusters (AuNCs). The ssDNA-AuNCs display improved fluorescence emission with excitation/emission maxima at 280/475nm after being incorporated with poly(diallyldimethylammonium chloride) (PDDA). Fluorescent enhancement is mainly attributed to the electrostatic interactions occurring between PDDA and ssDNA templates. This can make the conformation of the ssDNA templates tochange. Thus, it offers a better microenvironment for stabilizing and protecting ssDNA-AuNCs, and results in fluorescence emission enhancement. By using protamine as a model, the method is employed for the determination of trypsin. The assay enables trypsin to be determined with good sensitivity and a linear response ranging from 5ng⋅mL-1 to 60ng⋅mL-1 with a 1.5ng⋅mL-1 limit of detection. It is also extended to determine the trypsin contents in human's serum samples with recoveries between 98.7% and 103.5% with relative standard deviations (RSDs) between 3.5% and 4.8%. A novel fluorescent strategy has been developed for of trypsin determination by using protamine mediated fluorescent enhancement of DNA templated Au nanoclusters.

Polyelectrolyte complex-derived adsorbent capsules capable of selective recovery of precious metal from multiple mixtures

Polyelectrolyte complexes (PECs) are valuable functional materials for many industrial applications, yet it is difficult to augment their morphologies for desired applications. Herewith, PEC capsules were strategically fabricated via salt-induced coacervation of poly(diallyldimethylammonium chloride) and poly(styrenesulfonate). The adsorbents showed Au(III) selectivity in multimetal mixtures of Au-Pt-Pd and Au-Cu-Co-Zn. The binding sites were offered by R4N+ through electrostatic attraction, as elucidated with XPS. Selectivity was influenced by concentration, contact time and stirring speed. A new phenomenon of competing ion rejection was established to be caused by combined Au(III)/water penetration into the capsules, leading to decrease in bulk solution volume at equilibrium. The maximum Au(III) uptake was 176.63 ± 15.57 and 110.84 ± 2.32 mg/g for the Au-Pt-Pd and Au-Cu-Co-Zn systems, achievable within ∼ 1 and > 6 h, respectively. The loaded Au(III) was eluted with 0.1 M thiourea and regenerated for at least five cycles, making it practically feasible for resource recovery through urban mining.

Stabilization of calcareous subgrade soils with polyelectrolytes: mechanisms and mechanical properties

ABSTRACT Organic polyelectrolytes, i.e. anionic poly(sodium 4-styrenesulphonate) (PSS), cationic poly(diallyldimethylammonium chloride) (PDADMAC) and their polyelectrolyte complexes (PECs) were evaluated for stabilisation of calcareous sandy subgrade soil. This paper investigated the effects of polymer type, surface charge type of PEC, concentrations of PEC solutions and dosages of polymer solutions added to the soil on improvement of soil mechanical properties. We found that anionic polymers, for both PECs and individual polyelectrolytes, were superior to their cationic counterparts in improving soil strength. Besides, the constituent polyelectrolytes, PSS and PDADMAC, worked better than their PECs for the specific soil investigated. The strength of polymer-treated soils was also found to increase with the increase in dosages of the polymer solutions as well as curing periods. Furthermore, polymer-treated soil specimens exhibited significant toughness improvement, which was higher than cement-treated samples. Scanning electron microscopy images revealed the abundance of long palygorskite fibres covering the surfaces of larger calcite and dolomite particles and linking surrounding aggregates after adding polymers. This observation suggests the interconnection of palygorskite fibres and their linking networks between and among coarse aggregates as the likely mechanism of polymer stabilisation of the soil studied.

SARS-CoV-2 detection enabled by a portable and label-free photoelectrochemical genosensor using graphitic carbon nitride and gold nanoparticles

Fast, sensitive, simple, and cheap sensors are highly desirable to be applied in the health system because they improve point-of-care diagnostics, which can reduce the number of cases of infection or even deaths. In this context, here we report the development of a label-free genosensor using a screen-printed electrode modified with 2D-carbonylated graphitic carbon nitride (c-g-C3N4), poly(diallyldimethylammonium) chloride (PDDA), and glutathione-protected gold nanoparticles (GSH-AuNPs) for photoelectrochemical (PEC) detection of SARS-CoV-2. We also made use of Arduino and 3D printing to miniaturize the sensor device. The electrode surface was characterized by AFM and SEM techniques, and the gold nanoparticles by UV–Vis spectrophotometry. For SARS-CoV-2 detection, capture probe DNA was immobilized on the electrode surface. The hybridization of the final genosensor was tested with a synthetic single-strand DNA target and with natural saliva samples using the photoelectrochemistry method. The device presented a linear range from 1 to 10,000 fmol L−1 and a limit of detection of 2.2 and 3.4 fmol L−1 using cpDNA 1A and 3A respectively. The sensibility and accuracy found for the genosensor using cpDNA 1A using biological samples were 93.3 and 80% respectively, indicating the potential of the label-free and portable genosensor to detect SARS-CoV-2 RNA in saliva samples.

Highly sensitive and selective detection of enrofloxacin residues in chicken based on solution-gated graphene field-effect transistors

Enrofloxacin (ENR) has been widely used in poultry farming because of its low cost and high efficiency, yet ENR residues due to improper use may cause severe damage to human body. Herein for effective control of ENR residues, we report an ultra-sensitive ENR sensor based on a solution-gated graphene field-effect transistor (SGGT) through modification of the gate with Au nanoparticles and multi-walled carbon nanotube, dispersed by poly diallyl-dimethyl ammonium chloride (PDDA). The detection limit of the optimized SGGT-based sensor was as low as 10 nM (3.59 ng/mL) for ENR, and the linear range was 300 nM ∼ 30 μM (107.7 ng/mL ∼ 107.7 μg/mL).The prepared sensor was applied to ENR-spiked chicken samples, and the detection recoveries were 94.47% ∼ 105.95%. Considering the low-cost and easy manufacturing features of the SGGT-based sensor, we expect that it offers a highly sensitive sensing platform for on-site and real-time detection of ENR residues in many other food samples.

Synergistic antibacterial and biofilm eradication activity of quaternary-ammonium compound with copper ion

Antibiotics overuse and misuse increase the emergence of multidrug-resistant bacterial strains, which often leads to the failure of conventional antibiotic therapies. Even worse, the tendency of bacteria to form biofilms further increases the therapeutic difficulty, because the extracellular matrix prevents the penetration of antibiotics and triggers bacterial tolerance. Therefore, developing novel antibacterial agents or therapeutic strategies with diverse antibacterial mechanisms and destruction of bacteria biofilm is a promising way to combat bacterial infections. In the present study, the combination of quaternary ammonium compound poly(diallyl dimethyl ammonium chloride) (PDDA) with Cu2+ was screened out to fight common pathogenic Staphylococcus aureus (S. aureus) through multi-mechanisms. This combination appeared strong synergistic antibacterial activity, and the fractional inhibitory concentration index was as low as 0.032. The synergistic antibacterial mechanism involved the destruction of the membrane function, generation of intracellular reactive oxygen, and promotion more Cu2+ into the cytoplasm. Further, the combination of PDDA and Cu2+ reduced the extracellular polysaccharide matrix, meanwhile killing the bacteria embedded in the biofilm. The biocompatibility study in vitro revealed this combination exhibited low cytotoxicity and hemolysis ratio even at 8 times of minimum bactericidal concentration. This work provides a novel antibacterial agents combination with higher efficiency to fight planktonic and biofilm conditions of S. aureus.

Effective photodegradation of antibiotics by guest-host synergy between photosensitizer and bismuth vanadate: Underlying mechanism and toxicity assessment

The removal of antibiotics in wastewater has attracted increasing attention. Herein, a superior photosensitized photocatalytic system was developed with acetophenone (ACP) as the guest photosensitizer, bismuth vanadate (BiVO4) as the host catalyst and poly dimethyl diallyl ammonium chloride (PDDA) as the bridging complex, and used for the removal of sulfamerazine (SMR), sulfadiazine (SDZ) and sulfamethazine (SMZ) in water under simulated visible light (λ > 420 nm). The obtained ACP-PDDA-BiVO4 nanoplates attained a removal efficiency of 88.9%–98.2% for SMR, SDZ and SMZ after 60 min reaction and achieved kinetic rate constant approximately 10, 4.7 and 13 times of BiVO4, PDDA-BiVO4 and ACP-BiVO4, respectively, for SMZ degradation. In the guest-host photocatalytic system, ACP photosensitizer was found to have a great superiority in enhancing the light absorption, promoting the surface charge separation-transfer and efficient generation of holes (h+) and superoxide radical (·O2−), greatly contributing to the photoactivity. The SMZ degradation pathways were proposed based on the identified degradation intermediates, involving three main pathways of rearrangement, desulfonation and oxidation. The toxicity of intermediates was evaluated and the results demonstrated that the overall toxicity was reduced compared with parent SMZ. This catalyst maintained 92% photocatalytic oxidation performance after five cyclic experiments and displayed a co-photodegradation ability to others antibiotics (e.g., roxithromycin, ciprofloxacin et al.) in effluent water. Therefore, this work provides a facile photosensitized strategy for developing guest-host photocatalysts, which enabling the simultaneous antibiotics removal and effectively reduce the ecological risks in wastewater.

Critical parameters for highly efficient and reproducible polyelectrolyte multilayer coatings for protein separation by capillary electrophoresis

Since the introduction of polyelectrolyte multilayers to protein separation in capillary electrophoresis (CE), some progress has been made to improve separation efficiency by varying different parameters, such as buffer ionic strength and pH, polyelectrolyte nature and number of deposited layers. However, CE is often overlooked as it lacks robustness compared to other separation techniques. In this work, critical parameters for the construction of efficient and reproducible Successive multiple ionic-polymer layers (SMIL) coatings were investigated, focusing on experimental conditions, such as vial preparation and sample conservation which were shown to have a significant impact on separation performances. In addition to repeatability, intra- and inter-capillary precision were assessed, demonstrating the improved capability of poly(diallyldimethylammonium chloride) / poly(sodium styrene sulfonate) (PDADMAC / PSS) coated capillaries to separate model proteins in a 2 M acetic acid background electrolyte when all the correct precautions are put in place (with run to run%RSD(tm) < 1.8%, day to day%RSD(tm) < 3.2% and cap to cap%RSD(tm) < 4.6%). The approach recently introduced to calculate retention factors was used to quantify residual protein adsorption onto the capillary wall and to assess capillary coating performances. 5-layer PDADAMAC / PSS coatings led to average retention factors for the five model proteins of ∼4×10−2. These values suggest a relatively low residual protein adsorption leading to reasonably flat plate height vs linear velocity curves, obtained by performing electrophoretic separations at different electrical voltages (-10 to -25 kV).

Electrochemical sensing platform with gold nanoparticles capped by PDDA for benzyl alcohol determination

An electrochemical sensor has been developed, by modifying screen-printed carbon devices (SPCE) with photochemically synthesized gold nanoparticles (AuNP), to determine benzyl alcohol, a preservative widely used in the cosmetic industry. To obtain the AuNP with the best properties for electrochemical sensing applications, the photochemical synthesis was optimized using chemometric tools. A response surface methodology based on central composite design was used to optimize the synthesis conditions, as irradiation time, and the concentrations of metal precursor and the capping/reducing agent (poly(diallyldimethylammonium) chloride, PDDA). The anodic current of benzyl alcohol on SPCE modified with the AuNP was used as response of the system. The best electrochemical responses were obtained using the AuNP generated by irradiating for 18 min a 7.20 times 10−4 mol L−1 AuCl4−-1.7% PDDA solution. The AuNP were characterized by transmission electron microscopy, cyclic voltammetry and dynamic light scattering. The nanocomposite-based sensor formed by the optimal AuNP (AuNP@PDDA/SPCE) was used to determine benzyl alcohol by linear sweep voltammetry in 0.10 mol L−1 KOH. The anodic current at + 0.017 ± 0.003 V (vs. AgCl) was used as analytical signal. Detection limit obtained under these conditions was 2.8 µg mL−1. The AuNP@PDDA/SPCE was applied to determine benzyl alcohol in cosmetic samples.Graphical

Nano aluminum-based hybrid flocculant: Synthesis, characterization, application in mine drainage, flocculation mechanism

Given the characteristics of high turbidity and trace emulsified oil in mine drainage, which leads to the problems of low settling efficiency and poor treatment efficiency in the coagulation/flocculation treatment process, there is an urgent need to develop efficient, economical, and stable flocculants. In this study, a new hybrid flocculant Al-P(AM-DMDAAC-BA) was synthesized by the solution copolymerization method, and its viscosity, molecular weight, and cationic degree were 1492.93 mL/g, 7.44 × 106 Da and 16.97%, respectively. The physical and chemical properties of Al-P(AM-DMDAAC-BA) were characterized by Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (1H and 13C NMR), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Thermogravimetric (TG), and Zeta potential. SEM, Zeta potential, and laser particle size measurement characterized the properties of flocs. Batch wastewater treatment experiments analyzed the flocculation treatment efficacy. The results of the analysis are as follows. Aluminum hydroxyl complexes were attached to organic polymers via -Al-O-C- bonds. Acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC) and butyl acrylate (BA) were linked to each other by Carbon-carbon double bond (-CC-). The aluminum-based complex is dispersed as nano-microspheres in the hybrid flocculant and cross-linked to the organic branched chains. Al-P(AM-DMDAAC-BA) is thermally stable and less susceptible to thermal decomposition. It possesses strong electrical neutralization ability and rapid floc growth ability. It has excellent turbidity removal (reduced to 7.96 ± 1.15 NTU) and emulsified oil removal (reduced to 0.23 ± 0.01 mg/L) performance. The flocculation mechanism is mainly attributed to the electro-neutralization of the hybrid flocculants and the adsorption bridging effect of organic branched chains.

Molecular Structure Engineering of Polyelectrolyte Bilayer-Based Memristors: Implications for Linear Potentiation and Depression Characteristics

Critical to artificial intelligence’s future is emulating biological synapses with memristors. Moreover, according to a wide variety, low cost, simple fabrication, and good flexibility, organic materials provide a competitive approach in memristor and synapse emulation, especially in devices where ions carry current. Polyelectrolytes with different molecular structures were used as functional layers in this study to enhance the memory and synapse performance of polyelectrolyte bilayer-based memristors, performed by ions, and polyelectrolyte chain migration caused a potential drop change at the interface of the ∼15 nm thick polyelectrolyte bilayer and its electrodes. Consequently, the memory device with strong polyelectrolyte sodium poly(styrene sulfonic acid) (PSS) and poly(diallyl dimethylammonium chloride) (PDAC), which were prepared by spin-coating, shows outstanding resistive switching performance and synapse functionalities than those with weak polyelectrolytes and/or polyelectrolytes without a ring structure. Particularly, the indium tin oxide (ITO)/PSS/PDAC/ITO device shows almost linear potentiation and depression characteristics by applying continuous pulse voltage, which results in high performance on the artificial neural network simulation as 90% on the Mixed National Institute of Standards and Technology data set. The steric hindrance between the two polyelectrolytes with the five-ring structure can be attributed to the causation of linear conductance update. Furthermore, it shows short- and long-term plasticity during potentiation and depression, which is essential for the development of neuromorphic systems with complex cognitive capabilities.

PDDA/Honey Antibacterial Nanofiber Composites for Diabetic Wound-Healing: Preparation, Characterization, and In Vivo Studies.

In this paper, Poly (diallyldimethylammonium chloride) (PDDA)/honey nanofiber wound dressing composites were prepared and their effects on the diabetic wound-healing was evaluated using in vivo experiments. The release of effective compounds and the solubility of nanofibers were controlled through the crosslinking process by glutaraldehyde. The crosslinked nanofibers (crosslinking time was 3 h) showed an absorption capacity at a maximum value of 989.54%. Interestingly, the resultant composites were able to prevent 99.9% of Staphylococcus aureus and Escherichia coli bacteria. Furthermore, effective compounds were continuously released from nanofibers for up to 125 h. In vivo evaluation indicated that the use of PDDA/honey (40/60) significantly enhanced wound-healing. On the day 14th, the average healing rate for samples covered by conventional gauze bandage, PDDA, PDDA/honey (50/50), and PDDA/honey (40/60) were 46.8 ± 0.2, 59.4 ± 0.1, 81.7 ± 0.3, and 94.3 ± 0.2, respectively. The prepared nanofibers accelerated the wound-healing process and reduced the acute and chronic inflammation. Hence, our PDDA/honey wound dressing composites open up new future treatment options for diabetic wound diseases.

An eco-friendly method to prepare superwetting composites by modifying cotton with TA/FeIII/PDDA coatings for highly effective separations of emulsions

Separating oil/water mixtures and emulsions is an important global topic. Accordingly, it is imperative to prepare superwetting materials for the efficient separation of oily wastewater. Herein, we report an eco-friendly method for preparing multifunctional superwetting cotton-based materials without using organic solvents. Pristine cotton was modified with tannic acid (TA)/ferric ion (FeIII)/poly(diallyldimethylammonium chloride) (PDDA) coatings to form TA/FeIII/PDDA@cotton. The as-prepared TA/FeIII/PDDA@cotton exhibited superhydrophilicity (both in air and underoil), underwater superoleophobicity, and underoil water sorption property, and could be applied for both surfactant-stabilized oil-in-water (SOW) and water-in-oil (SWO) emulsion separations possessing excellent separation performance. The separation fluxes of the SOW and SWO emulsions were 38,600 and 246,000 L m−2 h−1 bar−1, respectively. The oil content in all SOW emulsion filtrates was <20 ppm, and the oil purities in all SWO emulsion filtrates were >99.96 wt%. In addition, our TA/FeIII/PDDA@cotton could be successfully used for the separation of dye-containing aqueous solutions and dye-spiked emulsions. Because of the outstanding separation performance of the oil/water mixtures and emulsions, the as-prepared TA/FeIII/PDDA@cotton exhibited remarkable potential for practical applications.

Magnetic-driving giant multilayer polyelectrolyte microcapsules for intelligent enhanced oil recovery

With the worldwide energy crisis breaking out, the global demand for petroleum is increasing tremendously. However, it is still a major challenge to improve oil recovery from oil reservoirs in the petroleum industry. Here, the multilayer giant polyelectrolyte microcapsules (PEM), sodium dodecyl benzene sulfonate-Fe3O4 @ (polyacrylamine hydrochloride/polystyrene sulfonate)3-poly(N-isopropylacrylamide-co-diallyl dimethyl ammonium chloride) (SFe@(PAH/PSS)3-PND), were prepared through electrostatic self-assembly technique. PND was polymerized from N-isopropylacrylamide (NIPAM) and dimethyl diallyl ammonium chloride (DMDAAC). The oil recovery efficiency of the polyelectrolyte microcapsules was all higher than 50 %, and which was significantly increased to over 70 % after heating above the lower critical solution temperature (LCST). Attributed to the temperature-adjusted intelligent mechanisms of the NIPAM molecular in PND, the contraction of NIPAM molecular chains affected with high temperature, coupled with the reduction of microcapsule volume, led to expansion of the pores in the capsule walls, which significantly increased the permeability of SDBS. Meanwhile, oil droplets combined with SDBS were encapsuled with the hydrophobic PND layer based on hydrophobic interaction, part of which entered into amphiphilic phospholipid core layer. Inspired by cellular cytokinesis, the SFe@ (PAH/PSS)3-PND was capable of intelligently capturing and carrying oil droplets driven with magnetism. The oil recovery efficiency of SFe@ (PAH/PSS)3-PND significantly improved and were all more than 78 % after heating above the LCST With magnetron drive, which is much higher than the traditional method. Hence, this work revealed the novel approaches in potential applications for intelligent enhanced oil recovery (EOR) in the petroleum industry.

Carboxylated Cellulose Nanocrystals Decorated with Varying Molecular Weights of Poly(diallyldimethylammonium chloride) as Sustainable Antibacterial Agents

Cationic nanomaterials are promising candidates for the development of effective antibacterial agents by taking advantage of the nanoscale effects as well as other exceptional physicochemical properties of nanomaterials. In this study, carboxylated cellulose nanocrystals (cCNCs) derived from softwood pulp were coated with cationic poly(diallyldimethylammonium chloride) of varying molecular weights. The resulting cationic carboxylated cellulose nanocrystals coated with poly(diallyldimethylammonium chloride) (cCNCs-PDDA) nanomaterials were characterized for their structural and morphological properties using Fourier transform infrared spectroscopy, dynamic light scattering, zeta potential, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. Cationic cCNCs-PDDA were investigated for their antibacterial properties against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli 23934 and Pseudomonas aeruginosa using a bacterial lawn growth inhibition assay. cCNC-PDDA materials displayed marked antibacterial activity, particularly against Gram-positive Staphylococcus aureus. Overall, our results indicated that cCNCs-PDDA could be a potential candidate for antibacterial applications such as antibacterial surfaces or coatings.

Utilization of host assisted aggregation-induced emission of ANS dye for ATP sensing

Photoemission efficiency of certain organic dyes gets augmented many fold when they are aggregated in solution. This AIE (Aggregation induced emission) property of dyes opens up new horizon in bio-imaging, fluorescence sensing of bio-analytes, molecular electronics, optoelectronics, chemical sensor etc. Herein, we report AIE enhancement of anionic ANS dye (8-anilinonaphthalene-1-sulfonic acid) aided by multi-cationic polymeric host, PAMA [poly(diallyl dimethyl ammonium) chloride] in aqueous solution. Anionic ANS loses its negative charge partially through charge neutralization at the vicinity of poly cationic PAMA host, leading to the reduction of like charge repulsion between the ANS molecules. This helps the dye molecules to stick together by π-π interaction, forming an aggregated assembly. Hence, there is a substantial reduction in torsional motion of the dye molecules, which is ultimately expressed as significant enhancement in its fluorescence intensity. The interaction of ANS dye with host polymer PAMA is primarily electrostatic in nature as indicated by ionic strength dependent study. This prompted the ANS-PAMA complex to be used as fluorescence probe to detect and quantify an important charged bio-analyte ATP (Adenosine triphosphate) in serum matrix at physiological pH 7.2, exhibiting the applicability of the studied system in the field of bio-sensing.