Discrete water domains in hydrophobic environment find relevance in aerosols, oil refinery, the human body, etc. The interfacial microstructure plays a crucial role in the stability of such water domains. Over the decades, the amphiphile-induced electrostatic interaction is considered to be the major stabilizing factor operating at these interfaces. Here we take the representative water/AOT/oil microemulsion to show that creating a strong Hbonding network through suitable additive, such as protic ionic liquid (IL) at the interface, helps both the growth and stability of water domains in the hydrophobic phase. On the other hand, common electrolytes and aprotic ILs fail to replicate such behavior as seen by Raman, Fourier transform infrared spectroscopy, dynamic light scattering (DLS), and electron microscopy measurements. Experimental results are further supported by the all-atomic molecular dynamics (MD) simulations that showed extended Hbonding mediated by the protic IL cations that were localized at the interface. High temperature DLS and rheology studies have shown greater thermal stability and mechanical strengths of our biocompatible microemulsions, which have potential to become suitable templates for in situ synthesis of nanoparticle and various organic compounds.

We report a highly sensitive electrochemical and fluorescence sensor for the detection of toxic environmental pollutant Hg2+ ions by using a novel dextrin‐cysteine‐Schiff base (DCS). The sensor is developed by the periodate oxidation of dextrin followed by Schiff base formation with an amino acid, cysteine. The new characterized DCS is used as an efficient and selective sensor for the detection of Hg2+ ions in aqueous solution both by electrochemical and fluorescence quenching process. The detection limit (LOD) by the electrochemical method is 0.74 nM which is much lower than that by the fluorometric detection, where LOD value is found to be 40.93 μM. The Schiff base/glassy carbon electrode (DCS/GCE) shows an excellent selectivity towards Hg2+ ions compare to other environmentally relevant ions where almost nil current response is observed. The DCS/GCE also exhibits remarkable sensing of Hg2+ in real water samples such as river and tap water. The electrochemical sensing of Hg2+ by DCS is found to be superior to that of fluorescence sensing.

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This paper presents burning rates as a function of pressure of several propellant formulations based on ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene cured by isophorone diisocyanate, many of which exhibit significantly low (nearly zero or negative) values of the pressure exponent of the burning rate in distinct pressure ranges, termed as plateau burning rate trends. The propellants contain a bimodal distribution of AP particles with the size of the coarse and fine particles within narrow ranges whose mean values are widely separated. Two mean sizes of fine particles were considered for the propellant formulations in the present work, namely, 5 and 20 µm. These choices are based on the mid-pressure extinction behavior exhibited by the matrix of fine AP and binder contained in the propellants but when tested alone over a wide range of fine AP size and pressure. The propellants that include the fine AP/binder matrixes exhibiting a mid-pressure extinction, in turn, exhibit the plateau burning rate trends within the corresponding pressure ranges. A plateau is also observed at elevated pressures in the burning rates of some formulations, which is related to the diminishing relative importance of the near-surface leading-edge region of the oxidizer/fuel diffusion flame in the gas-phase combustion zone. The choice of the coarse AP size influences the exact pressure range within the mid-pressure extinction domain of the matrix where the propellant exhibits the plateau burning rate trends.Key words: composite solid propellants, plateau burning rate trends, mid-pressure extinction, bimodal distribution.It is well known [1] that a low value of the pressure exponent of the burning rate of a solid propellant is desirable to improve the design margin of solid rocket motors. A low (zero or negative) value of the pressure exponent also reduces the sensitivity of the pressure developed in the combustion chamber of the rocket motor to the initial temperature of the propellant. Quasisteady homogeneous one-dimensional (QSHOD) analy-

Simultaneous electrochemical detection of Hg2+ and Cd2+ ions and catalytic reduction of 4NP to 4AP using a novel synthesized graft copolymer/CuO@Au NPs composite.

Reverse micelle (RM) aggregates have a wide range of applications in various areas of science and technology. A continuous demand exists to replace interfacial surfactant molecules with various nonconventional amphiphiles. Ionic liquid (IL)-like surfactants (IL-surf’s) constitute a class of such molecules that are being researched extensively. Here, we have formulated several water/IL-surf/oil microemulsions by optimizing the core droplet size with varying oil phases. The best composition of water/[BMIM]­[AOT]/IPM ([BMIM]­[AOT]: 1-butyl-3-methylimidazolium dioctyl sulfosuccinate; IPM: isopropyl myristate) was then analyzed in detail through experimental and computer simulations. Our results from DLS measurements suggest a structural transition from spherical aggregates in the parent water/[Na]­[AOT]/IPM solution to cylindrical droplets in the IL-surf-based system. The Raman and ATR-FTIR spectral analysis suggest a variation in the microstructure of the water/oil interface due to the differential interaction of the counterions with AOT headgroups and water. Molecular dynamics simulation results provided the direct image of the interface showing a structured versus uneven water/oil interface in [Na]­[AOT] versus [BMIM]­[AOT] RMs, where the larger [BMIM] cations weakly bind with the AOT headgroups due to their low charge density. Finally, an application of this IL-surf-based formulation was tested by carrying out a Heck cross-coupling reaction that showed significantly higher yield under milder reaction conditions.

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A dual functional material fulfilling twin objectives; simultaneous sensing and adsorption of Pb2+ ions in an aqueous medium.