Tough polyvinyl alcohol-gelatin biological macromolecules ionic hydrogel temperature, humidity, stress and strain, sensors

High strength, high toughness and high sensitivity were some of the most popular characteristics of flexible sensors. However, the mechanical properties and reproducibility of current single biomacromolecule gelatin hydrogel sensors are lower, and few hydrogel sensors have been able to provide excellent mechanical properties and flexibility at the same time so far. To address this challenge, a simple method to prepare tough polyvinyl alcohol (PVA) and gelatin hydrogel was proposed in this study. The PVA-gelatin-Fe3+ biological macromolecules hydrogel was prepared by a freeze-casting-assisted solution substitution method, which exhibited high strength (2.5 MPa), toughness (7.22 MJ m-3), and excellent temperature, humidity, stress, strain, and human motion sensing properties. This combination of mechanical properties and flexibility makes PVA-gelatin biological macromolecules hydrogel a promising material for flexible sensing. In addition, an ionic immersion strategy could also impart multiple functions to the hydrogel and be applied to various hydrogel sensor materials. Thus, this work provided an all-around solution for the preparation of advanced and robust sensors with good application prospects.

Thermodynamic parameters of phenylglycine interaction with UO22+, La3+ and Zr4

Phenylglycine interactions with (UO₂²⁺, La³⁺ and Zr⁴⁺) transition metal ions were studied at different ionic strengths and different temperature degrees applying Bjerrum's method. The work determine and discuss both the thermodynamic stabilities and the degree of interactions [Formula: see text]. Also the work calculate and discuss the thermodynamic parameters of interactions of phenylglycine with (UO₂²⁺, La³⁺ and Zr⁴⁺). The variables that govern the interaction between phenylglycine and the metal ions under investigation were related to the nature of the amino acid reactive species as well as to the nature of M⁺ such as the valence and radius of the ion. It was observed that reactions between the M⁺ and L^- were the most likely to occur. It was determined that the pH values affect the degree of complex formation [Formula: see text] as well as the production of various reactive spices. When the range of degree of interaction was more than 0.5 and less than 1.15, forming 1:1 stoichiometric complex. Additionally, it was shown that the stability of the complexes produced between phenylglycine and M^Z+ increased in the subsequent order, which was in good accord with the Irving-Williams order.

Thermodynamic Parameters of Phenylglycine Interaction with UO22+, La3+ and Zr4+.. [DOI: 10.21203/rs.3.rs-1881732/v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The interactions between phenylglycine and some transition metal ions (UO22+,La3+ and Zr4+) were studied at three ionic strengths [(µ = 0.05, 0.10 and 0.15) M KNO3] and three temperatures [(25, 35 and 45) ºC] in aqueous media by using Bjerrum’s potentiometric technique. The stoichiometric and thermodynamic stability constants as well as the degree of complexation for all studied systems (\(\stackrel{-}{\text{n}}\)) were determined and discussed. The standard thermodynamic parameters (Δ pKº and Δlog Kº) and the thermodynamic parameter differences (ΔGº, ΔΔGº, ΔHº, ΔΔHº, ΔSº, and ΔΔSº) were calculated for all possible reactions. Advanced discussions of these functions as well as the factors that may control the complexation processes from the thermodynamic point of view have been reported.