No abstract

Polytetrafluoroethylene (PTFE) is a ubiquitous material used for implants and medical devices in general because of its high biocompatibility and inertness: blood vessel, heart, table jawbone, nose, eyes, or abdominal wall can benefit from its properties in case of disease or injury. Its expanded version, ePTFE is an improved version of PTFE with better mechanical properties, which extends its medical applications. A material as frequently used as ePTFE with these exceptional properties deserves a review of its main uses, developments, and possibility of improvements. In this systematic review, we examined clinical trials related to ePTFE‐based medical devices from the literature. Then, we excluded all trials using ePTFE as a control to test other devices. ePTFE‐coated stents, hemodialysis and bypass grafts, guided bone and tissue regeneration membranes, hernia and heart repair and other devices are reviewed. The rates of success using these devices and their efficiency compared to other materials used for the same purposes are reported. ePTFE appears to be more or just as efficient compared to them. Some success rates remain low, suggesting the need of improvement ePTFE for medical applications.

Wet etching of polytetrafluoroethylene by sodium naphthalenide dissolved in diglyme solution was investigated experimentally and theoretically. First, the irreversible modification of the polymer surface was analyzed by Raman and XPS spectroscopies, water wetting angle measurements and AFM observations. The drastic changes brought to the surface of PTFE could be clearly demonstrated by these analytical methods. Then, first principle calculations coupled to molecular dynamics (FPMD) were performed to simulate the first steps of the reaction involved in the process of surface modification. It has been shown that fluorine directly attacks vicinal sodium with formation of a pair of sodium fluoride ions without grafting of the naphthalene moiety onto the modified surface. While the formation of the alkene and alkyne bond can be modelized, no spectroscopic signature is observed after rinsing etched PTFE.