RESUMO
The application of hydrogels in an underwater environment is limited due to their swelling behavior and the existence of a hydration layer. In this study, a hydrogel based on poly(sulfobetaine methacrylate) (PSBMA), tannic acid (TA) and montmorillonite (MMT) was prepared with excellent anti-swelling properties and underwater self-adhesion properties. The PSBMA hydrogel has excellent anti-swelling properties due to the strong electrostatic interaction between charged groups of PSBMA chains. Inspired by marine mussels, tannic acid modified montmorillonite (TA@MMT) was introduced. Natural polyphenol tannic acid, as a catechol donor, provides a large number of catechol groups for hydrogels. Montmorillonite acts as the physical cross-linking point of PSBMA chains through electrostatic interaction to improve the cohesion of the hydrogel. By combining the adhesion mechanism of zwitterions and catechol, the hydrogel maintains adhesion in air and underwater environments. In addition, a strain sensor was prepared based on the PSBMA/TA@MMT hydrogel, which can closely fit the human skin and stably monitor different movements in air and in underwater environments. Through a Bluetooth communication system, long-distance information transmission can be achieved. Therefore, the PSBMA/TA@MMT hydrogel broadens the application prospect of wearable devices in the underwater environment.
RESUMO
In this study, we report results of the interaction of titanium (Ti) with human synovial fluids. A wide palette of electrochemical techniques was used, including open circuit potential, potentiodynamic methods, and electrochemical impedance. After the electrochemical testing, selected surfaces were analyzed using Auger Electron Spectroscopy to provide laterally resolved information on surface chemistry. For comparison purposes, similar tests were conducted in a series of simulated body fluids. This study shows that compared to the tested simulated body fluids, synovial liquids show a large patient variability up to one order of magnitude for some crucial electrochemical parameters such as corrosion current density. The electrochemical behavior of Ti exposed to human synovial fluids seems to be controlled by the interaction with organic molecules rather than with reactive oxygen species.
