Influence of Shear Stress on Cationic Surfactant Uptake by Anionic Gels

Kinetic studies of cationic surfactant uptake by anionic polymer gel membrane under various shear flow have been performed, varying the alkyl chain length of surfactant, the ionic strength of surfactant solution, and the charge density of gel. By exposing the gel surface to a shear flow of ca. 1 Pa, the rate of surfactant uptake is distinctly enhanced, while the maximum binding ratio to the gel is not influenced. A linear relationship between the surfactant initial flux and shear stress has been established. At a high ionic strength, the effect of shear stress is suppressed, suggesting that the enhancement of surfactant uptake under shear flow is caused by a decrease in the surface electrostatic potential of the negatively charged polyelectrolyte gel, which favors the uptake of the positively charged surfactant. From the Nernst and Planck equation, a relationship between the surfactant uptake kinetics and the electrostatic field is derived that allows us to estimate the shear stress dependence of the change in the electrostatic field on the gel surface. The origin of the shear-induced surface electrostatic field change is discussed

Influence of Shear Stress on Cationic Surfactant Uptake by Anionic Gels

Kinetic studies of cationic surfactant uptake by anionic polymer gel membrane under various shear flow have been performed, varying the alkyl chain length of surfactant, the ionic strength of surfactant solution, and the charge density of gel. By exposing the gel surface to a shear flow of ca. 1 Pa, the rate of surfactant uptake is distinctly enhanced, while the maximum binding ratio to the gel is not influenced. A linear relationship between the surfactant initial flux and shear stress has been established. At a high ionic strength, the effect of shear stress is suppressed, suggesting that the enhancement of surfactant uptake under shear flow is caused by a decrease in the surface electrostatic potential of the negatively charged polyelectrolyte gel, which favors the uptake of the positively charged surfactant. From the Nernst and Planck equation, a relationship between the surfactant uptake kinetics and the electrostatic field is derived that allows us to estimate the shear stress dependence of the change in the electrostatic field on the gel surface. The origin of the shear-induced surface electrostatic field change is discussed

Influence of Shear Stress on Cationic Surfactant Uptake by Anionic Gels

Kinetic studies of cationic surfactant uptake by anionic polymer gel membrane under various shear flow have been performed, varying the alkyl chain length of surfactant, the ionic strength of surfactant solution, and the charge density of gel. By exposing the gel surface to a shear flow of ca. 1 Pa, the rate of surfactant uptake is distinctly enhanced, while the maximum binding ratio to the gel is not influenced. A linear relationship between the surfactant initial flux and shear stress has been established. At a high ionic strength, the effect of shear stress is suppressed, suggesting that the enhancement of surfactant uptake under shear flow is caused by a decrease in the surface electrostatic potential of the negatively charged polyelectrolyte gel, which favors the uptake of the positively charged surfactant. From the Nernst and Planck equation, a relationship between the surfactant uptake kinetics and the electrostatic field is derived that allows us to estimate the shear stress dependence of the change in the electrostatic field on the gel surface. The origin of the shear-induced surface electrostatic field change is discussed

Influence of Shear Stress on Cationic Surfactant Uptake by Anionic Gels

Kinetic studies of cationic surfactant uptake by anionic polymer gel membrane under various shear flow have been performed, varying the alkyl chain length of surfactant, the ionic strength of surfactant solution, and the charge density of gel. By exposing the gel surface to a shear flow of ca. 1 Pa, the rate of surfactant uptake is distinctly enhanced, while the maximum binding ratio to the gel is not influenced. A linear relationship between the surfactant initial flux and shear stress has been established. At a high ionic strength, the effect of shear stress is suppressed, suggesting that the enhancement of surfactant uptake under shear flow is caused by a decrease in the surface electrostatic potential of the negatively charged polyelectrolyte gel, which favors the uptake of the positively charged surfactant. From the Nernst and Planck equation, a relationship between the surfactant uptake kinetics and the electrostatic field is derived that allows us to estimate the shear stress dependence of the change in the electrostatic field on the gel surface. The origin of the shear-induced surface electrostatic field change is discussed

Influence of Shear Stress on Cationic Surfactant Uptake by Anionic Gels

Kinetic studies of cationic surfactant uptake by anionic polymer gel membrane under various shear flow have been performed, varying the alkyl chain length of surfactant, the ionic strength of surfactant solution, and the charge density of gel. By exposing the gel surface to a shear flow of ca. 1 Pa, the rate of surfactant uptake is distinctly enhanced, while the maximum binding ratio to the gel is not influenced. A linear relationship between the surfactant initial flux and shear stress has been established. At a high ionic strength, the effect of shear stress is suppressed, suggesting that the enhancement of surfactant uptake under shear flow is caused by a decrease in the surface electrostatic potential of the negatively charged polyelectrolyte gel, which favors the uptake of the positively charged surfactant. From the Nernst and Planck equation, a relationship between the surfactant uptake kinetics and the electrostatic field is derived that allows us to estimate the shear stress dependence of the change in the electrostatic field on the gel surface. The origin of the shear-induced surface electrostatic field change is discussed

Influence of Shear Stress on Cationic Surfactant Uptake by Anionic Gels

Kinetic studies of cationic surfactant uptake by anionic polymer gel membrane under various shear flow have been performed, varying the alkyl chain length of surfactant, the ionic strength of surfactant solution, and the charge density of gel. By exposing the gel surface to a shear flow of ca. 1 Pa, the rate of surfactant uptake is distinctly enhanced, while the maximum binding ratio to the gel is not influenced. A linear relationship between the surfactant initial flux and shear stress has been established. At a high ionic strength, the effect of shear stress is suppressed, suggesting that the enhancement of surfactant uptake under shear flow is caused by a decrease in the surface electrostatic potential of the negatively charged polyelectrolyte gel, which favors the uptake of the positively charged surfactant. From the Nernst and Planck equation, a relationship between the surfactant uptake kinetics and the electrostatic field is derived that allows us to estimate the shear stress dependence of the change in the electrostatic field on the gel surface. The origin of the shear-induced surface electrostatic field change is discussed

Influence of Shear Stress on Cationic Surfactant Uptake by Anionic Gels

Kinetic studies of cationic surfactant uptake by anionic polymer gel membrane under various shear flow have been performed, varying the alkyl chain length of surfactant, the ionic strength of surfactant solution, and the charge density of gel. By exposing the gel surface to a shear flow of ca. 1 Pa, the rate of surfactant uptake is distinctly enhanced, while the maximum binding ratio to the gel is not influenced. A linear relationship between the surfactant initial flux and shear stress has been established. At a high ionic strength, the effect of shear stress is suppressed, suggesting that the enhancement of surfactant uptake under shear flow is caused by a decrease in the surface electrostatic potential of the negatively charged polyelectrolyte gel, which favors the uptake of the positively charged surfactant. From the Nernst and Planck equation, a relationship between the surfactant uptake kinetics and the electrostatic field is derived that allows us to estimate the shear stress dependence of the change in the electrostatic field on the gel surface. The origin of the shear-induced surface electrostatic field change is discussed

Rapid Self-Recoverable Hydrogels with High Toughness and Excellent Conductivity

Hydrogels as soft and wet materials have attracted much attention in sensing and flexible electronics. However, traditional hydrogels are fragile or have unsatisfactory recovery capability, which largely limit their applications. Here, a novel hydrogen bond based sulfuric acid–poly­(acrylic acid) (PAA)/poly­(vinyl alcohol) physical hydrogel is developed for addressing the above drawbacks. Sulfuric acid serves two functions: one is to inhibit the ionization of carboxyl groups from PAA chains to form more hydrogen bonds and the other is to provide conductive ions to promote conductivity of hydrogel. Consequently, the hydrogel obtains comprehensive mechanical properties, including extremely rapid self-recovery (strain = 1, instantly self-recover; strain = 20, self-recover within 10 min), high fracture strength (3.1 MPa), and high toughness (18.7 MJ m^–3). In addition, we demonstrate this hydrogel as a stretchable ionic cable and pressure sensor to exhibit stable operation after repeated loadings. This work provides a new concept to synthesize physical hydrogels, which will hopefully expand applications of hydrogel in stretchable electronics

Table_1_Ion-Induced Synthesis of Alginate Fibroid Hydrogel for Heavy Metal Ions Removal.DOCX

Design and synthesis of environmentally friendly adsorbents with high adsorption capacities are urgently needed to control pollution of water resources. In this work, a calcium ion-induced approach was used to synthesize sodium alginate fibroid hydrogel (AFH). The as-prepared AFH has certain mechanical strength, and the mechanical strength is enhanced especially after the adsorption of heavy metal ions, which is very convenient for the recovery. AFH exhibited excellent adsorption performances for Cu2+, Cd2+, and Pb2+ ions and displayed very high saturated adsorption capacities (Qe) of 315.92 mg·g−1 (Cu2+), 232.35 mg·g−1 (Cd2+), and 465.22 mg·g−1 (Pb2+) with optimized pH values (3.0–4.0) and temperature (303 K). The study of isotherms and kinetics indicated that adsorption processes of heavy metal ions fitted well with the pseudo-second-order kinetics model and the Langmuir model. Pb2+ was found to have the strongest competitiveness among the three heavy metal ions. Thus, AFH has great application prospects in the field of heavy metal ions removing from wastewater.</p

Rapid Self-Recoverable Hydrogels with High Toughness and Excellent Conductivity

Hydrogels as soft and wet materials have attracted much attention in sensing and flexible electronics. However, traditional hydrogels are fragile or have unsatisfactory recovery capability, which largely limit their applications. Here, a novel hydrogen bond based sulfuric acid–poly­(acrylic acid) (PAA)/poly­(vinyl alcohol) physical hydrogel is developed for addressing the above drawbacks. Sulfuric acid serves two functions: one is to inhibit the ionization of carboxyl groups from PAA chains to form more hydrogen bonds and the other is to provide conductive ions to promote conductivity of hydrogel. Consequently, the hydrogel obtains comprehensive mechanical properties, including extremely rapid self-recovery (strain = 1, instantly self-recover; strain = 20, self-recover within 10 min), high fracture strength (3.1 MPa), and high toughness (18.7 MJ m^–3). In addition, we demonstrate this hydrogel as a stretchable ionic cable and pressure sensor to exhibit stable operation after repeated loadings. This work provides a new concept to synthesize physical hydrogels, which will hopefully expand applications of hydrogel in stretchable electronics