Viscoelastic properties of physical cellulosic bionogels of cholinium lysinate

Eucalyptus bleached kraft pulp-ionic liquid inks for 3D printing of ionogels and hydrogels

3D printing has been recently recognized as one of the most promising technologies due to the multiple options to fabricate cost-effective and customizable objects. However, the necessity to substitute fossil fuels as raw materials is increasing the research on bio-based inks with recyclable and eco-friendly properties. In this work, we formulated inks for the 3D printing of ionogels and hydrogels with bleached kraft pulp dissolved in [Emim][DMP] at different concentrations (1-4 wt%). We explored each ink's rheological properties and printability and compared the printability parameters with a commercial ink. The rheological results showed that the 3 % and 4 % cellulose-ionic liquid inks exhibited the best properties. Both had values of damping factor between 0.4 and 0.7 and values of yield stress between 1900 and 2500 Pa. Analyzing the printability, the 4 wt% ink was selected as the most promising because the printed ionogels and the hydrogels had the best print resolution and fidelity, similar to the reference ink. After printing, ionogels and hydrogels had values of the elastic modulus (G') between 10³ and 10⁴ Pa, and the ionogels are recyclables. Altogether, these 3D printed cellulose ionogels and hydrogels may have an opportunity in the electrochemical and medical fields, respectively.

Investigating the Correlation between Electrolyte Concentration and Electrochemical Properties of Ionogels

Ionogels are hybrid materials comprising an ionic liquid confined within a polymer matrix. They have garnered significant interest due to their unique properties, such as high ionic conductivity, mechanical stability, and wide electrochemical stability. These properties make ionogels suitable for various applications, including energy storage devices, sensors, and solar cells. However, optimizing the electrochemical performance of ionogels remains a challenge, as the relationship between specific capacitance, ionic conductivity, and electrolyte solution concentration is yet to be fully understood. In this study, we investigate the impact of electrolyte solution concentration on the electrochemical properties of ionogels to identify the correlation for enhanced performance. Our findings demonstrate a clear relationship between the specific capacitance and ionic conductivity of ionogels, which depends on the availability of mobile ions. The reduced number of ions at low electrolyte solution concentrations leads to decreased ionic conductivity and specific capacitance due to the scarcity of a double layer, constraining charge storage capacity. However, at a 31 vol% electrolyte solution concentration, an ample quantity of ions becomes accessible, resulting in increased ionic conductivity and specific capacitance, reaching maximum values of 58 ± 1.48 μS/cm and 45.74 F/g, respectively. Furthermore, the synthesized ionogel demonstrates a wide electrochemical stability of 3.5 V, enabling diverse practical applications. This study provides valuable insights into determining the optimal electrolyte solution concentration for enhancing ionogel electrochemical performance for energy applications. It highlights the impact of ion pairs and aggregates on ion mobility within ionogels, subsequently affecting their resultant electrochemical properties.

Ionogels: recent advances in design, material properties and emerging biomedical applications

Ionic liquid (IL)-based gels (ionogels) have received considerable attention due to their unique advantages in ionic conductivity and their biphasic liquid-solid phase property. In ionogels, the negligibly volatile ionic liquid is retained in the interconnected 3D pore structure. On the basis of these physical features as well as the chemical properties of well-chosen ILs, there is emerging interest in the anti-bacterial and biocompatibility aspects. In this review, the recent achievements of ionogels for biomedical applications are summarized and discussed. Following a brief introduction of the various types of ILs and their key physicochemical and biological properties, the design strategies and fabrication methods of ionogels are presented by means of different confining networks. These sophisticated ionogels with diverse functions, aimed at biomedical applications, are further classified into several active domains, including wearable strain sensors, therapeutic delivery systems, wound healing and biochemical detections. Finally, the challenges and possible strategies for the design of future ionogels by integrating materials science with a biological interface are proposed.

Electrode Kinetics of Ion Jelly and Ion Sol-Gel Redox Materials on Screen-Printed Electrodes

Several hydrogel materials have been proposed for drug delivery systems and other purposes as interfacial materials, such as components for fuel cells and immobilization of biomolecules. In the present work, two materials, an ion sol-gel, based on 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and an ion jelly (1-ethyl-3-methylimidazolium ethylsulfate) film deposited on carbon screen-printed electrodes, were electrochemically characterized. The electrode kinetics of ion jelly and ion sol-gel materials were compared by using ferrocyanide/ferricyanide redox reaction couple as a model redox process. Diffusion coefficients were calculated and compared to those obtained with the model redox couple in non-modified electrodes. Results pointed to a decrease of two and four orders of magnitude in the diffusion coefficients, respectively, for ion jelly and ion sol-gel film modified electrodes. Heterogeneous electron transfer constants for the ferrocyanide/ferricyanide ion redox process were also determined for modified and non-modified electrodes, in which the ion sol-gel film modified electrode presented the lower values. This work sought to contribute to the understanding of these materials’ properties, with emphasis on their diffusion, conductivity, and electrochemical behavior, namely reversibility, transfer coefficients, and kinetics, and optimize the most suitable properties for different possible applications, such as drug delivery.

Cellulose ionogels, a perspective of the last decade: A review

Cellulose ionogels have been extensively studied due to the variability of their properties and applications. The capability of trapping an ionic liquid in a biodegradable solid matrix without losing its properties makes this type of material a promising substitute for fossil fuel-derived materials. The possibility to formulate ionogels chemically or physically, to choose between different ionic liquids, cellulose types, and the possibility to add a wide range of additives, make these ionogels an adaptable material that can be modified for each target application in many fields such as medicine, energy storage, electrochemistry, etc. The aim of this review is to show its versatility and to provide a summary picture of the advances in the field of cellulose ionogels formulation (chemical or physical methods), as well as their potential applications, so this review will serve as a stimulus for research on these materials in the future.

How does cholinium cation surpass tetraethylammonium cation in amino acid-based ionic liquids for thermal and structural stability of serum albumins?

In this study, we report how similarly two serum albumins (bovine serum albumin (BSA) and human serum albumin (HSA)) respond in the presence of different concentration of aromatic amino acid based ionic liquids (AAILs), which are cholinium tryptophan [CHO][Trp]IL and tetraethylammonium tryptophan [TEA][Trp]IL. Extended results of thermodynamic stability indicate the extent to which both serum albumins differ in their thermal stability despite having structural similarity in presence of AAILs. To efficiently quantify the results, biomolecular interactions studies were carried out between serum albumins and AAILs with the help of differential scanning calorimetry (DSC), dynamic light scattering (DLS) and various spectroscopic techniques. DSC results illustrated that both AAILs are increasing the thermal stability of BSA and HSA, as per transition temperature (T_m) values, BSA (65.51 to 72.46 °C) and HSA (65.46 to 75.97 °C) have more thermal stability in the presence of [CHO][Trp]IL as compare to [TEA][Trp]IL, BSA (65.51 to 69.75 °C) and HSA (65.46 to 72.08 °C). Secondary structure results obtained using Dichroweb software and selcon calculations. Furthermore, to illustrate the specific binding of AAIL's cations or anions with the binding sites of BSA and HSA, the molecular docking studies were also performed using Molegro trail version v 6.0.

Rheology of regenerated cellulose suspension and influence of sodium alginate

Cellulosic colloidal suspensions present unique opportunities for rheological modification of complex fluids. In this work, the rheological behavior of regenerated cellulose (RC) suspensions, including their oscillating shear and time-dependent behavior, as well as yield stress, were studied. The rheological effects of sodium alginate's addition to aqueous RC solutions subject to shear flow were investigated. The results reveal that the RC suspension exhibited "gel-like" behavior and had a shear-thinning property. At increasing RC concentrations, the suspensions' yield stress and the extent of viscosity recovery after plastic deformation had both increased. The viscoelastic suspensions underwent a transition from "solid-like" to "liquid-like" behavior upon sodium alginate's inclusion. Sodium alginate was found to enhance RC suspensions' viscosity recoverability. Furthermore, with increasing concentrations of sodium alginate, the yield stress of RC suspension began to decrease and then vanished, occurring below the 1:1 RC: sodium alginate weight ratio with total solid content fixed at 1 wt%, due to RC's inability to form an extended network RC. This study yields insights into the rheology of RC suspensions and the influence of sodium alginate and supports both their usage as rheological modifies in applications such as coatings, drug delivery systems, and additive manufacturing techniques such as 3D printing.