Electrical Double Layer at Various Electrode Potentials: A Modification by Vibration

This paper proposes a vibration model of ions as an improvement over the conventional Gouy–Chapman–Stern theory, which is used to model the electrical double layer capacitance and to study the ionic dynamics at electrode/electrolyte interfaces. Although the Gouy–Chapman–Stern model is successful for small applied potentials, it fails to explain the observed behavior at larger potentials, which are becoming increasingly important as materials with high charge injection capacities are developed. A time-dependent study on ionic transport indicates that ions vibrate near the electrode surface in response to the applied electric field. This vibration allows us to correctly predict the experimentally observed decreasing differential capacitance at high electrode potential. This new model elucidates the mechanism behind the ionic dynamics at solid–electrolyte interfaces, providing useful insight that may be applied to many electrochemical systems in energy storage, photoelectrochemical cells, and biosensing

Polycrystalline Diamond Coating of Additively Manufactured Titanium for Biomedical Applications

Additive manufacturing using selective laser melted titanium (SLM-Ti) is used to create bespoke items across many diverse fields such as medicine, defense, and aerospace. Despite great progress in orthopedic implant applications, such as for “just in time” implants, significant challenges remain with regards to material osseointegration and the susceptibility to bacterial colonization on the implant. Here, we show that polycrystalline diamond coatings on these titanium samples can enhance biological scaffold interaction improving medical implant applicability. The highly conformable coating exhibited excellent bonding to the substrate. Relative to uncoated SLM-Ti, the diamond coated samples showed enhanced mammalian cell growth, enriched apatite deposition, and reduced microbial <i>S. aureus</i> activity. These results open new opportunities for novel coatings on SLM-Ti devices in general and especially show promise for improved biomedical implants