Facile preparation and characterization of poly(vinyl alcohol)-NaCl-glycerol supramolecular hydrogel electrolyte

Holistically Engineered Polymer–Polymer and Polymer–Ion Interactions in Biocompatible Polyvinyl Alcohol Blends for High‐Performance Triboelectric Devices in Self‐Powered Wearable Cardiovascular Monitorings

“…Such a change is because the complexation between K + /Na + and the hydroxyl groups in PVA can lead to the formation of dense PVA chain entanglements and hence a reduced polymer coil size (from the case (7) to the case (9) in Figure 3c). [33,41] As for the effect of pH on the coil size, the largest coil size occurs at pH=7 (Figure 3b and case (5) in Figure 3c). Smaller coil size is observed at higher or lower pH conditions.…”

“…The ions can be displaced by the electric field, leading to an enhanced polarization and, eventually, an increased dielectric constant. Also, Na + or K + ions tend to form complexation with hydroxyl groups in PVA chains (Figures 2a-b), [33] which could breakdown the dense H-bonds in the PVA chains. Such a complexation process would enhance the mobility of polarized groups in PVA and increase the reorientation ability of the PVA chain when an electric field is applied.…”

“…[42] While in the basic condition, the ionization of carboxyl groups in gelatin generates an electrostatic repulsive force that stretches polymer chains to larger dimensions (i.e., larger coil sizes). [33] On the contrary, the complexation between the cation (Na + ) and -OH in PVA reduces the polymer coil size. Therefore, both the electrostatic repulsive force and the complexation effect come into play in determining the coil size of PVA-5G90-pH9 (case (6) in Figure 3c).…”

“…(3) The third group was used to investigate the effect of Na + and K + ions, which are two common ions in our daily life, in the human body, and closely related to human health. [47] The added ions are thought to lead to the formation of complex structures with hydroxyl groups in PVA chains, [33] which facilitates the reorientation of PVA dipoles and increases the dielectric constant of the PVA blends.…”

A Regenerable Hydrogel Electrolyte for Flexible Supercapacitors

“…First, the dissolution of PVA powder in water requires the assistance of high temperature, and a general addition of strong acid/basic such as H 2 SO 4 or NaOH is demanded to improve ionic conductivity of PVA aqueous solution, both of which allow easy oxidization of PVA and contribute to an unstable electrochemical performance. Second, the PVA electrolyte (generally used as a mixture of PVA/salt/water) with disordered physical cross-links shows a thick liquid form rather than a fixed shape ( Peng et al., 2018 ). This means a flexibility dependence of the electronic device on the electrodes and even substrates, which demands the extra use of separator and flexible substrates ( Lv et al., 2019 ), and even worse, increases the difficulty in maintaining structural integrity of the whole device and device's capacitance at high strains as well.…”