Aqueous Bromide Solutions Research Articles

Hydration number and allied parameters of aqueous solutions of ammonium bromide through ultrasonic study

Hydration number and allied parameters of aqueous solutions of ammonium bromide through ultrasonic study

Micellization, interaction forces and physicochemical parameters of tetradecyltrimethylammonium bromide in aqueous solution of crystal violet dye: Assessment of the influences of temperature, electrolytes and hydrotrope

The present study explores the interactions between tetradecyltrimethylammonium bromide (TTAB) and crystal violet (CV) dye in aq. Na-based electrolytes (NaCl, NaOAc, Na2SO4) and hydrotrope (sodium salicylate (NaSal)) media using conductometric technique. Physicochemical parameters (critical micelle concentration (CMC), degree of counter ion binding (β)) and thermodynamic variables (ΔGmo, ΔHmo, and ΔSmo)) were estimated. The CMC values of the study system were reduced with the increase of the concentrations of three Na-salts and the CMC values increased with the content of NaSal while the values increased with the escalation temperature. The spontaneous micellization of the TTAB+CV mixture was characterized by negative ΔGmo values. The ΔHmo and ΔSmo values expose the existence of hydrophobic interaction between TTAB and CV dye in aq. medium while these values connote the presence of electrostatic interaction along with hydrophobic interaction in aq. salts and NaSal media. Moreover, the molar heat capacity (ΔCm0), the thermodynamic of transfer (ΔGm,tr0, ΔHm,tr0 and ΔSm,tr0) and enthalpy–entropy compensation parameters for TTAB+CV mixture were estimated and analyzed with proper reasoning. The findings contribute to a deeper understanding of the interaction dynamics between TTAB and CV dye in aq. solutions of salts and NaSal environments, providing valuable insights for applications in relevant fields.

Motility and pairwise interactions of chemically active droplets in one-dimensional confinement.

Self-propelled droplets serve as ideal model systems to delve deeper into understanding the motion of biological microswimmers by simulating their motility. Biological microorganisms are renowned for showcasing a diverse array of dynamic swimming behaviors when confronted with physical constraints. This study aims to elucidate the impact of physical constraints on swimming characteristics of biological microorganisms. To achieve this, we present observations on the individual and pairwise behavior of micellar solubilized self-propelled 4-cyano-4'-pentyl-biphenyl (5CB) oil droplets in a square capillary channel filled with a surfactant trimethyl ammonium bromide aqueous solution. To explore the effect of the underlying Péclet number of the swimming droplets, the study is also performed in the presence of additives such as high molecular weight polymer polyethylene oxide and molecular solute glycerol. The capillary confinement restricts droplet to predominantly one-dimensional motion, albeit with noticeable differences in their motion across the three scenarios. Through a characterization of the chemical and hydrodynamic flow fields surrounding the droplets, we illustrate that the modification of the droplets' chemical field due to confinement varies significantly based on the underlying differences in the Péclet number in these cases. This alteration in the chemical field distribution notably affects the individual droplets' motion. Moreover, these distinct chemical field interactions between the droplets also lead to variations in their pairwise motion, ranging from behaviors like chasing to scattering.

Influence of pH on spectroscopic and interfacial features of phenol in aqueous cetrimonium bromide solutions of different concentrations

Phenol is an aromatic compound with toxic effects on the environment and living organisms. Cetrimonium bromide (CTAB) is a cationic, quaternary ammonium surfactant, constituent in industrial formulations, and is employed for solubilization as well as removal of pollutants. This study explores the impact of pH on the behavior of phenol in the micellar solution of CTAB via UV–Visible spectroscopy and surface tension measurements at room temperature. Binding coefficient (Kb), free energy change of binding (ΔGb), change in molar absorptivity (Δε), partition coefficient (Kc), free energy change of partitioning (ΔGp) and number of molecules per micelle (n) were determined at different pH. Results showed that phenol exhibits no appreciable interaction with the CTAB, however phenolate ions have the tendency to bind with CTAB micelles and penetrate in the palisade layer of CTAB.Surface properties such as surface excess (τmax), minimum area per molecule (Amin), packing parameter (P), surface area per head group (as), free energy changes of micellization (ΔGm), adsorption ΔGads, and transfer (ΔGtrans), and surface pressure (Π) for CTAB, and phenol in CTAB solutions were also determined. Interfacial studies supported the role of phenol in facilitating micellization of CTAB thermodynamically and hence a fall in CMC values of CTAB except for pH 7.11. Calculated interfacial parameters established the influence of phenol over rearrangement and surface adsorption of CTAB molecular ions at air/water interface. Surface tension results also showed that unionized phenol molecules have low surface activity (62.23mN/m), but when phenol is ionized into phenolate ion surface dramatically increased (44.17 mN/m).

Effect of glycerol on micellization of quasi-binary mixture of zwitterionic cocamidopropyl hydroxysultaine and cetyltrimethylammonium bromide in aqueous solution

The micellization behavior of quasi-binary mixture of zwitterionic cocamidopropyl hydroxysultaine (CAPHS) with cationic cetyltrimethylammonium bromide (CTAB) was investigated both in aqueous solution and in glycerol-water. Both the tensiometric and the conductive techniques were adopted to determine the critical micelle concentrations (cmc) of individual and mixed surfactants. In the framework of the regular solution theory and based on the pseudophase separation model, some micellization and thermodynamic parameters were estimated by the Rubingh’s and the Clint’s models. The results indicate that the nonideal mixing of CAPHS with CTAB and the synergistic interaction between them play vital roles on the reduction of mixed cmc, the amplitude of synergistic interaction depends on the composition of mixture and the presence of glycerol induces the increase in the individual and mixed cmc values and the change of the participation of CAPHS in mixed micelle with the composition in bulk solution. The electrostatic repulsion, the diversity of molecular conformation and the steric hindrance can account for the formation of mixed micelle and the difference in micellar composition. Thermodynamic parameters show that the entropy makes overwhelming contributions on the spontaneous process of micellization, the release of mixing heat makes the stable mixed micelle formed and the presence of glycerol makes for reducing the contribution of entropy and forming the more stable mixed micelle. These findings help with understanding the interaction behavior between two species and the effect of glycerol and further providing some information for the design of the related surfactant formulations.

The effect of external and operating conditions on a solar Lithium Bromide absorption chiller

The excessive consumption of fossil energies (electrical energy) during summer caused by the technological development involves more and more climate warming, in order to relieve insistency between electric supply and demand, heat driven absorption chillier is pretty promising, it consists on using heat (solar) as motive energy to provide cold energy. The single effect absorption cycle is the simplest absorption cycle, it’s composed of four main components which are all heat exchangers using a diversity couple of refrigerant. Lithium bromide aqueous solution is one of many others solutions widely used in the absorption chiller for cooling purposes; it possesses several advantages over the other type of absorption systems, such as It highest coefficient of performance compared to other absorption units at the same conditions. A simple flat plat collector can assume the energy required for heating the solution in the generator. Even though, LiBr solution may cause the problem of the crystallization and the limitation of this machine on cooling did not affect the economical aspect of LiBr absorption chiller. The main aim of this article is to study the effect of thermal and environmental parameters each compound of an absorption chiller which produce a cool power equal to 1 kW.

Preparation and Physicochemical Characterization of Phosphonium-Based Ionic Liquids Containing Carboxylate Anions

Ionic liquids (ILs) are organic salts composed of cation and anion with melting points below 100°C. They have unique characteristic features.1) ILs are also promising liquid materials available for various applications because their function can be easily controlled by changing the combination of cations and anions and by introducing substituents. Among the numerous ILs, considerable ILs based on carboxylate anions have been reported. On the other hand, several published papers reported ILs based on quaternary phosphonium cations, demonstrating relatively high transport properties and thermal stability2). We report here the preparation and physicochemical properties of ILs based on triethyloctylphosphonium (P2228) and tributyloctylphosphonium (P4448) cations together with various carboxylate anions.The intermediate hydroxides were obtained by adding an anion exchange resin (Amberlite IRN78 OH) into the precursor bromide aqueous solutions. Equimolar amounts of carboxylic acids (formic, acetic, propionic, butyric and octanoic acids) were added to the hydroxide solutions to form carboxylate-based phosphonium salts. The salts obtained were isolated by evaporation and then were dried under high vacuum at 50 °C. The physicochemical properties of ILs, e.g. density, viscosity, conductivity and thermal decomposition temperature were measured.Table 1 shows the physicochemical properties of the ILs at 25 °C. P2228-PrCO2 became a solid at room temperature, while P2228-HCO2, P2228-MeCO2, and P2228-EtCO2 became viscous liquids at room temperature. Furthermore, all P4448-based salts became viscous liquids at room temperature. The density of each IL was increased with decreasing the carbon numbers of the alkyl chains in carboxylate anions. The number density also showed similar tendency to the density. These results indicate that the number density of the formate was the highest since the anion size was the smallest. The viscosity of each ILs was decreased with increasing the carbon numbers of the alkyl chains in carboxylate anions. Although the details of the relationship between measured viscosity and the carbon numbers of the alkyl chains in carboxylate anions still remain unclear at present, it is thought to be the charge distribution of the anions is one of the factors. The acetate-, propionate-, butyrate-, and octanoate-based ILs showed high thermal decomposition temperatures around 270 to 300°C. However, the formate-based ionic liquid showed lower thermal stability, which might be due to the decarboxylation of the formate anion. Figure 1

Effect of antidiabetic drug metformin hydrochloride on micellization behavior of cetylpyridinium bromide in aqueous solution

Herein, the interaction of an antidiabetic drug, metformin hydrochloride (MHCl), and a cationic surfactant, cetylpyridinium bromide (CPB) is investigated in an aqueous medium. The critical micellar concentration (CMC) of CPB is estimated through conductivity experiments and found to be reduced on adding MHCl and further decreased in the presence of NaCl. The reduced CMC is attributed to the solubilization of MHCl by CPB through micellization and the micellization is found to be thermodynamically spontaneous that experiences an augmentation in the presence of NaCl. This is identified from the negative value of standard free energy ( Δ G0 m). The higher negative value of Δ G0 m (-55.41 kJ mol−1) for CPB + MHCl + NaCl than CPB (-37.89 kJ mol−1) and CPB + MHCl (-34.08 kJ mol−1) is suggestive of the above phenomenon. The positive values of Δ S0 m in all three cases confirm that the micellization is entropy driven. The binding of MHCl on CPB is quantified by estimating binding constant using the Benesi-Hildebrand (B-H) plot through UV-visible spectral methods. The binding constant values were calculated to be 2.70 M−1 for CPB + MHCl + NaCl compared to 1.258 M−1 for CPB + MHCl predicting a favoring of micellization in the presence of NaCl which is higher than that in the presence of co-solvents. The molecular interaction of MHCl and CPB is justified using FT-IR and NMR techniques. The surface properties of drug surfactant interactions are assessed using SEM techniques. The point of interaction between the drug and surfactant is visualized through the molecular docking approach. The results suggest that CPB would be an effective solubilizer for developing MHCl drug formulations. Communicated by Ramaswamy H. Sarma

Salt effects on the reactivity for ligand substitution reactions of [Ru(CN)5OH2]3− anion with two naphthalene substituted ligands (nitroso‐R‐salt and α‐nitroso‐β‐naphthol) in presence of Tetrapropylammonium bromide (Pr4NBr) and Sodium chloride (NaCl)

AbstractThe kinetics of the ligand exchange reaction between aquapentacyanoruthenate(II) [Ru(CN)5OH2]3− ion and naphthalene substituted ligands [α‐nitroso‐β‐naphthol (αNβN), and nitroso‐R‐salt (NRS)] has been studied in aqueous salt solutions of sodium chloride (NaCl) or tetrapropylammonium bromide (Pr4NBr) salt. The kinetics was monitored spectrophotometrically at 525 nm corresponding to the λmax of reddish‐brown‐colored substituted products, [Ru(CN)5(αNβN)]3− or [Ru(CN)5(NRS)]3−. Increasing the ionic strength of the reaction mixture using NaCl, exerted a negative salt effect on the rate of formation of naphthalene‐substituted products. At the same time, an increment in the concentration of Pr4NBr imparted a positive salt effect on the reaction. The observed rate constant (kobs) exhibits linear increment with respect to the concentration of NRS or αNβN while remaining invariant with variation in [Ru(CN)5OH2]3−. The computed activation parameters for NRS (∆H# = 24.55 kJ mol−1, Ea = 27.03 kJ mol−1, ∆G# = 87.83 kJ mol−1, and ∆S# = – 212.5 J K−1 mol−1) and αNβN ((∆H# = 17.33 kJ mol−1, Ea = 19.81 kJ mol−1, ∆G# = 87.87 kJ mol−1, and ∆S# = – 236.7 J K−1 mol−1) also support the proposed mechanism.

Waste Heat Recycling Absorption Refrigeration Circulation System

To maximize energy use, this paper designs a lithium bromide absorption refrigeration system that is used to recycle and use low-temperature energy and industrial residual heat. Firstly, the mathematical model of the system is established using the lithium bromide aqueous solution status equation and the equation of the state of water and steam to obtain the state parameters in the thermodynamic calculation process of the system. Secondly, according to the principle of mass economy, energy saving, and heat transfer, the thermodynamic parameters of each process of the system are obtained to assist the design of the system. Finally, the influence of some key parameters on the system is simulated and analyzed to obtain the optimal parameters which can make the system recovery efficiency the highest. The simulation results show that the system conceived in this article can efficiently recycle waste gas and achieve the purpose of refrigeration. Therefore, it has a certain value of popularization.

Synthesis, Photophysics and Optical Limiting Properties of Functionalized Benzofuran Derivatives

AbstractA series of functionalized benzofuran derivatives (2,3,4) have been strategically synthesized and characterized via NMR spectra and high resolution mass spectrometry. To enhance the solubility in organic common solvents, long alkyl groups were introduced into the parent skeletons in compounds2 b,3 b,4 b. The photophysical properties were examined in a comparative manner. The self‐assembly behaviors were further studied, indicating that the regular nanostructures could be tuned by the change of the ratio of THF and cetyltrimethylammonium bromide (CTAB) aqueous solution. Moreover,3 bpresented nonlinear optical (NLO) response recorded through open‐aperture Z‐scan way. The threshold of3 bwas 2.08 J/cm2, which is lower than that of the state‐of‐the‐art material C60(4.01 J/cm2) under the similar operation condition, implying that such molecule might be promising optical limiting (OL) materials.

Tunable molecular packing modes via H- or J-aggregates in the supramolecular helical nanostructures from an achiral C3 symmetric molecule.

The self-assembly of a C3-symmetric molecule benzene-1,3,5-tricarboxylate substituted with methyl cinnamate (BTECM) has been investigated by a reprecipitation method in H2O and cetyltrimethylammonium bromide (CTAB) aqueous solution, respectively. The nanostructures and characteristics of the assemblies were monitored by UV-Vis spectroscopy, fluorescence (FL) spectroscopy, circular dichroism (CD) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that helical nanostructures were successfully assembled from the achiral C3 molecule BTECM. More importantly, the helices aggregated via different packing modes in H2O and CTAB aqueous solution. In H2O, the nanostructures underwent a process of particles, fibers and helices via H-type aggregate upon aging. In the case of CTAB aqueous solution (1.2 mM), the helices were translated from particles and the molecules were inclined to aggregate via the J-type mode. In addition, the aggregation process could be accelerated by raising the temperature proved by UV-Vis spectra. A molecular aggregation mechanism was proposed based on the experimental results.

Dielectric Relaxation of Ion-pairs, Micelles and Hydration in Aqueous Hexyltrimethylammonium Bromide Solutions

Through dielectric measurements of aqueous n-hexyltrimethylammonium bromide solutions, the structure and dynamics of ion-pairs, micelles, and water are investigated as functions of concentration and temperature. The frequency range of the study was ∼ 0.2 ≤ν/GHz ≤ 89, and the concentrations were changed from 0.0448 to 0.8476 mol.dm−3 at 298.15 K. The effects of temperature (278.15 ≤ T/K ≤ 338.15) on two selected solutions with concentrations above and below the critical micelle concentration were examined. A summation of three Debye processes fits the complex permittivity data of solutions with concentrations below the critical micelle concentration. To fit the spectra above the critical micelle concentration, a summation of five Debye processes is needed. Below the critical micelle concentration, solutes relax due to the tumbling motion of solvent-shared ion pairs. The two micelle relaxation processes that have been seen are the result of free and bound counter ions tangentially and radially diffusing around the charged micelles. Maxwell-Wagner relaxation is equivalent to the high frequency micelle relaxation process. Both the solvent and micelle dispersion provide acceptable volume fractions. Hexyltrimethylammonium behaves like higher n-alkyltrimethylammonium micelles in the context of micelle relaxation. Before critical micelle concentration, the cations, anions, and ion pairs strongly hydrate a total of ∼18 ± 4 non-rotational water molecules. Beyond the critical micelle concentration, there are an additional ∼ 5 ± 2 non-rotational water molecules in addition to ∼ 15 ± 3 slower-moving water molecules in the hydrophobic hydration shell.

Molecular dynamics simulations of interfacial structure, dynamics, and interfacial tension of tetrabutylammonium bromide aqueous solution in the presence of methane and carbon dioxide.

The interfacial behavior of tetrabutylammonium bromide (TBAB) aqueous solutions in the absence of gas and the presence of methane and carbon dioxide gases is studied by molecular dynamics simulations. The aqueous TBAB phase, at concentrations similar to the solid semiclathrate hydrate (1:38 molratio), has a smaller interfacial tension and an increase in the gas molecules adsorbed at the interface compared to that in pure water. Both these factors may contribute to facilitating the uptake of the gases into the solid phase during the process of semiclathrate hydrate formation. At similar gas pressures, CO2 is adsorbed preferentially compared to CH4, giving it a higher surface density, due to the stronger intermolecular interactions of CO2 molecules of the solution at the interface. The increase in relative adsorption of CH4 at the solution surface compared to that in pure water surface is due to the hydrophobic interactions between the n-alkyl chains of the TBA+ cation and methane gas.

Influence of tetraalkylammonium salts on the adsorption kinetics of bovine serum albumin in aqueous solutions at the air-liquid interface

Bovine serum albumin adsorption dynamics in water and in aqueous solutions of tetramethylammonium bromide, hexyltrimethylammonium bromide octyltrimethylammonium bromide, decyltrimethylammonium bromide, and dodecyltrimethylammonium bromide at the air-liquid interface was studied at a temperature of 298.15 K.The kinetics of the adsorption process of the biomolecule in water and in the aqueous alkylammonium solutions was investigated following the changes in surface tension with time. The measurements were performed on a high-precision drop volume tensiometer.The surface pressure data were adjusted with two of the most used semi-empirical kinetic models that describe the process of adsorption and allow the determination of the equilibrium adsorption parameters.The results in water and in the aqueous solutions containing tetraalkylammonium salts show that the adsorption kinetics is well described by a model consisting of three steps in which the transport of the protein in the initial stage is diffusion controlled. After some time, the rate is determined by the adsorption and the penetration of the protein at the air-liquid interface and the rearrangement of the protein at the interface; the evolution of both processes is described by steps that follow first-order rate equations.The results indicate that the overall adsorption process of bovine serum albumin BSA in water and the aqueous alkylammonium salts solutions is controlled by the second step which is the slowest of the three steps; it corresponds to the adsorption and penetration of the biomolecule at the air-liquid interface.

Effect of 1-Butyl-1-methylpyrrolidinium trifluoromethanesulfonate on water activity of ternary aqueous ionic liquid solutions containing [BMIm]Br, [BMIm]Cl, [HMIm]Br, and [HMIm]Cl, at 298.15 K

In improved isopiestic method, the effect of 1-butyl 1-methylpyrrolidinium trifluoromethanesulfonate ([BMP][TfO]) on the activity of water of aqueous solutions of 1-butyl 3-methyl imidazolium bromide ([BMIm]Br), 1-butyl 3-methyl imidazolium chloride ([BMIm]Cl), 1-hexyl 3-methyl imidazolium bromide ([HMIm]Br), and 1-hexyl 3-methyl imidazolium chloride ([HMIm]Cl) was determined. Some quantities of vapor liquid equilibrium were calculated from the experimental values. The activity coefficients of [BMIm]Br, [BMIm]Cl, [HMIm]Br, and [HMIm]Cl in binary and ternary systems were calculated by the results obtained from correlating the activity of water measured in these systems with TNRF-mNRTL local composition based model. Through it, the transfer of these ionic liquids from water to aqueous ternary solutions containing [BMP][TfO] was investigated with respect to the transfer Gibbs energy. The interactions between solute and solvent were highlighted using the transfer Gibbs energy, water activity and partial pressure of water data.

Studies of radial distribution function and second virial coefficient for surfactant decyltrimethylammonium bromide in aqueous solutions at 298.15 K: Evidence for cation–cation hydrophobic interactions effect

Excess internal pressure of solution and excess partial molar volume of solute data embedded in the parameter reversible isothermal work (W) have been used to calculate the ion–ion pair correlation functions (gij(r), r being distance) and the thermodynamic properties of aqueous solutions of decyltrimethylammonium bromide (C10TAB) in concentration range 0.01 – 0.14 mol∙kg–1. It is observed that gij(r) exhibits a peak at critical micelle concentration (cmc), while the virial coefficient term (gij(r) – 1) also goes through a maximum. Using Friedman's methodology and McMillan–Mayer theory of solutions, these results have been examined. With the help of concept of Gurney cosphere around the ions, the overlap of solvation shells (water molecules) as the concentration of ions increases have been used to probe water– structure effects as water–structure making/breaking. Coefficients Aij are estimated (Coulombic term, a core repulsive term, a cavity formation term and overlap of cosphere term) at various concentrations of ionic surfactant and at a radial distance of 20 Å for a micellar entity. Further analysis indicates that gij parameter (that is, representing cation–cation interaction g++) dominate over g+– (representing ion–solvent interaction) in solution phase. Thus for a self–assembly process (formation of micelle with aggregation number) in a solution phase is being characterized by a peak in gij(r) function at cmc and aggregation number of ≈ 38, area under the peak, while the virial coefficient variation indicates a dominance of cation–cation interaction and cosphere water–structural effects. It is emphasized that the approach adopted by us to use excess PV work to estimate gij(r) is better to understand the thermodynamic process involved in self–assemblies and micelle formation.

Volumetric and Acoustic Studies of Interactions between L-Phenylalanine and 1-Hexyl-3-Methylimidazolium Bromide in Aqueous Solution

Experimental density (ρ) and ultrasonic velocity (c) for phenylglycine in ( 0.01, 0.03, 0.05 and 0.05) mol.kg−1 aqueous solutions of 1-hexyl-3-methylimidazolium bromide at T = (313.15 and 318.15) K. Collected values for density and ultrasonic velocity were used to compute the apparent molar volumes (V f ), the apparent molar volumes at infinite dilution (), partial molar isentropic compression (K f ,s ) and partial molar isentropic compression at infinite dilution (). Also recorded data of these mixtures were utilized to calculate pair and triplet interaction coefficients. Such thermodynamic characteristics can be used to investigate the solvation behaviour, structure formation, and many sorts of interactions in (phenylglycine + water + 1-hexyl-3-methylimidazolium bromide) ternary solutions.

ELECTROCHEMICAL DISSOLUTION OF TITANIUM ELECTRODES POLARIZED BY ALTERNATING CURRENT IN A HYDROBROMIC ACID AQUEOUS SOLUTION

The work shows the patterns of electrochemical dissolution of titanium electrodes polarized by alternating current in an aqueous solution of hydrogen bromide. The current density (200-1200 A/m2), hydrogen bromide concentration (1.0-5.0 M), electrolysis duration (0.25-2.0 hours), and electrolyte temperature depend on the current rate of the titanium electrode in the alternating current source (20°C-80°C) were considered. The maximum value of current yield was obtained at a current density of 400 A/m2 when titanium electrodes were polarized by an alternating current and it was recorded that the current yield is reduced at a high current density. It is shown that the current output for titanium increases directly proportional to the concentration of hydrogen bromide, i.e., hydrogen ion content. The order of the reaction which occurs during the electrolysis of hydrogen bromide is determined. It is proved that the current efficiency of dissolving titanium in the alternating current source decreases when the electrolysis time is increased, as the electrolysis products in the electrolyte settle down on the electrode surface. It is shown that as the temperature of the electrolyte solution is increased, the current output value for dissolving titanium rises to 48%. The activation energy determined according to the temperature-kinetic regime was 17.76 kJ/mol, the process was carried out according to the diffusion-kinetic regime. It was shown that titanium is dissolved in hydrogen bromide aqueous solution to form titanium (III) ions. The influence of the main parameters on the electrochemical dissolution of a polarized alternating current titanium electrode in hydrochloric acid is investigated and effective ways of titanium dissolution are considered. The results of the research can be used to propose a new method of titanium waste recycling and increase the potential of titanium electrode usage in production.

Fabrication of channeled scaffolds through polyelectrolyte complex (PEC) printed sacrificial templates for tissue formation.

One of the pivotal factors that limit the clinical translation of tissue engineering is the inability to create large volume and complex three-dimensional (3D) tissues, mainly due to the lack of long-range mass transport with many current scaffolds. Here we present a simple yet robust sacrificial strategy to create hierarchical and perfusable microchannel networks within versatile scaffolds via the combination of embedded 3D printing (EB3DP), tunable polyelectrolyte complexes (PEC), and casting methods. The sacrificial templates of PEC filaments (diameter from 120 to 500 μm) with arbitrary 3D configurations were fabricated by EB3DP and then incorporated into various castable matrices (e.g., hydrogels, organic solutions, meltable polymers, etc.). Rapid dissolution of PEC templates within a 2.00 M potassium bromide aqueous solution led to the high fidelity formation of interconnected channels for free mass exchange. The efficacy of such channeled scaffolds for in vitro tissue formation was demonstrated with mouse fibroblasts, showing continuous cell proliferation and ECM deposition. Subcutaneous implantation of channeled silk fibroin (SF) scaffolds with a porosity of 76% could lead to tissue ingrowth as high as 53% in contrast to 5% for those non-channeled controls after 4 weeks. Both histological and immunofluorescence analyses demonstrated that such channeled scaffolds promoted cellularization, vascularization, and host integration along with immunoregulation.