Polymer-Metal Nanocomposites Containing Dual-Function Metal Nanoparticles: Ion-Exchange Materials Modified with Catalytically-Active and Bactericide Silver Nanoparticles

Flexible capacitive pressure sensor with high sensitivity and wide detection range applying solvent-exchanged porous lignin-cellulose hydrogel as the dielectric layer

Recently, the application of flexible sensors for wearable devices has attracted much attention from researchers. This study reports a capacitive pressure sensor with a solvent-exchanged porous lignin-cellulose hydrogel as the dielectric layer (SPLCH). The detection range and sensitivity of the sensor were modulated by adjusting the ratio of alkaline lignin(AL) and sodium lignosulfonate(SL). The existence of the porous structure and the ester bonds generated by cross-linking were demonstrated by material characterization experiments. The compression modulus of SPLCH is in the range of 310-320 kPa. The capacitive pressure sensing prepared in this way has a sensitivity of 5.18kPa-1 and 2.87kPa-1, a wide detection range (0-185.22 kPa), a short response-recovery time (25-50 ms), a low detection limit (1.875 Pa), and a good stability of repetitive loading (20,000 cycles) within two phases, respectively, which is finally applied practically in the detection of breathing, swallowing, human motion signals, speech recognition, pedometers, and Morse code information transmission scenarios. It provides a new idea for future porous structure fabrication processes and utilization of lignin to prepare flexible capacitive pressure sensors with high detection range and high sensitivity.

Multifunctional Heterogeneous Ion-Exchange Membranes for Ion and Microbe Removal in Low-Salinity Water

Here, multifunctional heterogeneous ion-exchange metal nanocomposite membranes were prepared for surface water desalination and bacterial inactivation under low-pressure (0.05 MPa) filtration conditions. Ultrafiltration (UF) heterogeneous ion exchange membranes (IEMs) were modified with different concentrations of AgNO₃ and CuSO₄ solutions using the intermatrix synthesis (IMS) technique to produce metal nanocomposite membranes. Scanning electron microscopy (SEM) images revealed that the metal nanoparticles (MNPs) (Ag and Cu) were uniformly distributed on the surface and the interior of the nanocomposite membranes. With increasing metal precursor solution concentration (0.01 to 0.05 mol·L^-1), the metal content of Ag and Cu nanocomposite membranes increased from 0.020 to 0.084 mg·cm^-2 and from 0.031 to 0.218 m·cm^-2 respectively. Results showed that the hydrodynamic diameter diameters of Ag and Cu nanoparticles (NPs) increased from 62.42 to 121.10 nm and from 54.2 to 125.7 nm respectively, as the metal precursor concentration loaded increased. The leaching of metals from metal nanocomposite membranes was measured in a dead-end filtration system, and the highest leaching concentration levels were 8.72 ppb and 5.32 ppb for Ag and Cu, respectively. The salt rejection studies indicated that ionic selectivity was improved with increasing metal content. Bacterial filtration showed higher antibacterial activity for metal nanocomposite membranes, reaching 3.6 log bacterial inactivation.

Polyurethane foams doped with stable silver nanoparticles as bactericidal and catalytic materials for the effective treatment of water

Reusable dual-purpose nanocomposite foams with AgNPs showed high stability even after 2 years of storage.

Uncommon patterns in Nafion films loaded with silver nanoparticles

The synthesis of Ag-NPs inside Nafion produced unexpected patterns that can reveal the real morphology of the polymer.