Deep eutectic solvents (DESs) are an emerging class of mixtures characterized by significant depressions in melting points compared to those of the neat constituent components. These materials are promising for applications as inexpensive "designer" solvents exhibiting a host of tunable physicochemical properties. A detailed review of the current literature reveals the lack of predictive understanding of the microscopic mechanisms that govern the structure−property relationships in this class of solvents. Complex hydrogen bonding is postulated as the root cause of their melting point depressions and physicochemical properties; to understand these hydrogen bonded networks, it is imperative to study these systems as dynamic entities using both simulations and experiments. This review emphasizes recent research efforts in order to elucidate the next steps needed to develop a fundamental framework needed for a deeper understanding of DESs. It covers recent developments in DES research, frames outstanding scientific questions, and identifies promising research thrusts aligned with the advancement of the field toward predictive models and fundamental understanding of these solvents.

Organosoluble silver nanoparticles (AgNPs) have been synthesized for the first time in a task-specific, halide-free, deep eutectic solvent (DES) using a simple and convenient wet chemical reduction route involving microwave (MW) heating with oleylamine (OAm) acting as a surfactant and reducing agent. Nanoparticle formation is extremely rapid and occurs within 30 s of microwave heating at 100 °C. The effects of various reaction parameters (e.g., synthesis temperature, MW irradiation time, maximal MW power, water content of the medium) on the size and uniformity of the prepared AgNPs have been elucidated in this study. The produced colloidal AgNPs were characterized using UV–vis spectroscopy and transmission electron microscopy (TEM), with the aim of identifying reaction parameters simultaneously achieving optimal particle yield and colloid uniformity. This work illustrates how the versatile nature of DESs can be exploited to create unconventional DESs designed for nanoscale tasks for which conventional (e.g., halide-containing) DESs may be poorly suited, further expanding the repertoire of these solvents as sustainable media for various nanoapplications.

We have investigated the textural properties, electrochemical supercapacitances and vapor sensing performances of bamboo-derived nanoporous carbon materials (NCM). Bamboo, an abundant natural biomaterial, was chemically activated with phosphoric acid at 400 °C and the effect of impregnation ratio of phosphoric acid on the textural properties and electrochemical performances was systematically investigated. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of various oxygen-containing surface functional groups (i.e. carboxyl, carboxylate, carbonyl and phenolic groups) in NCM. The prepared NCM are amorphous in nature and contain hierarchical micropores and mesopores. Surface areas and pore volumes were found in the range 218–1431 m2 g−1 and 0.26–1.26 cm3 g−1, respectively, and could be controlled by adjusting the impregnation ratio of phosphoric acid and bamboo cane powder. NCM exhibited electrical double-layer supercapacitor behavior giving a high specific capacitance of c.256 F g−1 at a scan rate of 5 mV s−1 together with high cyclic stability with capacitance retention of about 92.6% after 1000 cycles. Furthermore, NCM exhibited excellent vapor sensing performance with high sensitivity for non-aromatic chemicals such as acetic acid. The system would be useful to discriminate C1 and C2 alcohol (methanol and ethanol).

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