Supramolecular Adhesives with Extended Tolerance to Extreme Conditions via Water-Modulated Noncovalent Interactions

Development of supramolecular adhesives with strong tolerance to extreme conditions has emerged as an important research area. In this study, by balancing supramolecular interactions such as hydrogen bonding interactions, electrostatic interactions, π–π stacking interactions, and cation-π interactions, we designed and prepared a series of two-component supramolecular adhesives derived from small organic molecules. Highly efficient interfacial adhesion with maximum adhesion strength of ≈10.0 MPa was realized on various surfaces in air, organic solvents, or liquid nitrogen. Owing to balanced supramolecular interactions, water participation prolonged and increased the tolerance of the adhesives in extreme environments. We demonstrate that the combination of imidazole-based ionic liquids and phenols can be applied for various interfacial adhesions, thereby aiding the development of next-generation adhesives capable of adapting to various extreme conditions in a controlled manner.     

Mixed Conductive,Injectable, and Fluorescent Supramolecular Eutectogel Composites

Eutectogels are an emerging family of soft ionic materials alternative to ionic liquid gels and organogels, offering fresh perspectives for designing functional dynamic platforms in water-free environments. Herein, the first example of mixed ionic and electronic conducting supramolecular eutectogel composites is reported. A fluorescent glutamic acid-derived low-molecular-weight gelator (LMWG) was found to self-assemble into nanofibrillar networks in deep eutectic solvents (DES)/poly(3,4-ethylenedioxythiophene) (PEDOT): chondroitin sulfate dispersions. These dynamic materials displayed excellent injectability and self-healing properties, high ionic conductivity (up to 10⁻² S cm⁻¹), good biocompatibility, and fluorescence imaging ability. This set of features turns the mixed conducting supramolecular eutectogels into promising adaptive materials for bioimaging and electrostimulation applications.     

A Model of Simple Liquids

The intuitively clear hole defect model can be used for quantitative estimates and for understanding the properties of liquids. An ideal liquid is defined in analogy with an ideal gas and corrected for real liquids with hole defects. The good agreement permits an application of this approximation process to the understanding of some important material properties. The effective model fills a gap in the area of applied chemistry and of chemical teaching. It also leads to a correction factor for the failure of the theorem of corresponding states. The reasons for the applicability of such a simple model are demonstrated on the basis of the Lennard-Jones potential.     

Applications of ultrasound in processing of liquid foods: A review

Ultrasonic processing of a variety of liquids, drinks and beverages has generated much interest with published literature papers increasing within this area in recent years. Benefits include enhanced emulsification with improved homogenization and fat globule size reduction being recorded. In dairy systems increased creaming rates are observed on sonication in a process known as fractionation. Whilst fruit juices exhibit retention or enhancement of quality parameters whilst increasing levels of bioactive compounds. Sterilization of liquids is a large feature of ultrasonic treatment with microbial activity of a range of fruit juices being monitored over time as increased stability and reduced spoilage is observed. Progress has also been made towards scale up of ultrasonic processes with several examples of batch and continuous processes being studied with reduced processing times and temperatures being quoted as a result of ultrasonic treatment. This short review covers the effect of sonication on liquids and beverages with a specific focus towards dairy and fruit juices and covers emulsification, fractionation, sterilization and some pilot scale initiatives.     

Surface and flexoelectric polarization in a nematic liquid crystal 5CB

The temperature dependence of the surface polarization has been measured for both the planar and homeotropic orientation of a nematic liquid crystal at a solid substrate. A conventional liquid crystal 5CB, pure and doped with an azo-dye, was used in cells with controlled asymmetry for light absorption. The measurements have been made by a pyroelectric technique using short pulses of a YAG laser to create a temperature increment. The latter, in turn, was measured independently by a novel time-resolved “optical thermometer” technique monitoring temperature-dependent birefringence by a He- Ne laser beam. In accordance with the symmetry of the order parameter, the surface polarization has different sign for the two orientations, its magnitude ranges from -4 to +2pC/m. The same technique has been used for the measurement of the flexoelectric polarization in hybrid cells. The sum of the flexoelectric coefficients is e ₁ + e ₃ = - 13pC/m at 25°C. Received 28 February 2000 and Received in final form 5 September 2000     

Quick and Easy Modification of Glassy Carbon Electrodes with Ionic Liquid and Tetraruthenated Porphyrins for the Electrochemical Determination of Atrazine in Water

Atrazine is a pesticide used to control broadleaf weeds, however its wide distribution and its high persistence in the soil and in surface waters has resulted in a public and environmental health problem. Present results shows the design, construction and characterization of glassy carbon electrodes modified with tetrarutenated metalloporphyrin (M=Ni (II) and Zn (II)) and 1‐butyl‐3‐methylimidazolium bis (trifluoromethylsulfonyl) imide, BMIMNTF₂. The modification was reproducible and sensitive for the electrochemical detection of atrazine in neutral media. The detection limit was 230 nM when using GC/BMIMNTF₂/ZnTRP and 540 nM with GC/BMIMNTF₂/NiTRP, meaning that his methodology can be a feasible and inexpensive way to detect atrazine in trace levels.     

Application of 1‐Allyl‐3‐(1‐butyl)imidazolium Chloride in the Synthesis of Cellulose Esters: Properties of the Ionic Liquid,and Comparison with Other Solvents

The ionic liquid (IL), 1‐allyl‐3‐(1‐butyl)imidazolium chloride (AlBuImCl), has been synthesized and its properties determined. Increase in the temperature increased its conductivity and decreased its density, polarity, and viscosity. Microcrystalline cellulose (MCC), dissolves in this IL by heating at 80 °C; this did not affect its degree of polymerization, decreased its index of crystallinity (Ic), and changed in morphology after regeneration. Convenient acylation of MCC was achieved by using 50% excess anhydride at 80 °C, for 24 or 48 h for acetic and butyric anhydride, respectively. The composition of the mixed esters depended on the initial ratio of the anhydrides, and their order of addition.

     

Environmentally benign and one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes catalyzed by acyclic Brønsted acidic ionic liquid [H-NMP][HSO4] under green conditions

A convenient and efficient direct protocol for the preparation of 14-aryl-14H-dibenzo[a,j]-xanthenes was described. The condensation of 2-naphthol with various aromatic aldehydes in the presence of a catalytic amount of [H-NMP][HSO₄] as a Brønsted acidic ionic liquid under solvent-free conditions at 110 °C was described. This method has the following advantages: the reaction workup is very easy, and the catalyst is smoothly recycled to catalyze the preparation of 14-aryl-14H-dibenzo[a,j]xanthenes with high yields through a green and one-pot procedure. The corresponding products have been obtained in excellent yields, with high purity, and in short reaction times.     

Water Purification and Microplastics Removal Using Magnetic Polyoxometalate‐Supported Ionic Liquid Phases (magPOM‐SILPs)

Filtration is an established water‐purification technology. However, due to low flow rates, the filtration of large volumes of water is often not practical. Herein, we report an alternative purification approach in which a magnetic nanoparticle composite is used to remove organic, inorganic, microbial, and microplastics pollutants from water. The composite is based on a polyoxometalate ionic liquid (POM‐IL) adsorbed onto magnetic microporous core–shell Fe₂O₃/SiO₂ particles, giving a magnetic POM‐supported ionic liquid phase (magPOM‐SILP). Efficient, often quantitative removal of several typical surface water pollutants is reported together with facile removal of the particles using a permanent magnet. Tuning of the composite components could lead to new materials for centralized and decentralized water purification systems.     

Rotational Diffusion in Prolate Symmetric top Molecules

A comparative analysis of theoretical and experimental rotational diffusion constants was performed for a series of liquid phase prolate symmetric top molecules. It was observed that the tumbling diffusion constants, D⊥, predicted by the extended Hynes-Kapral Weinberg (HKW) model were invariably in closer agreement with experiment than were values determined by the Hu-Zwanzig (HZ) slip model of molecular reorientation. The HKW theory also yielded superior estimates of D‖ for two -CCI³ rotors. However, the experimental spinning diffusion coefficients for methyl (-CD³) rotors were much closer to the slip (Free Rotor) limit.