New Bonding Method for Non-Adhesive Plastics
A research team of materials scientists has developed a method of bonding plastics that enables completely new applications. For example as heart valves to which hardly any blood adheres.
Heart valves regulate the blood flow to ensure that the body is supplied with enough blood. If they stop closing properly, for example due to a heart attack, artificial heart valves can fulfil the required function. However, blood platelets can easily stick to the metal surfaces of conventional artificial heart valves. In order to prevent the formation of blood clots, patients must therefore take medication for the rest of their lives. Certain blood-repellent plastics could serve as alternative materials. However, until now, they have been too soft to be used for heart valve replacements.
Mechanical bonding procedure without chemicals
A research team from the Institute for Materials Science at Kiel University (CAU), in cooperation with the University Medical Center Schleswig-Holstein (Lübeck campus), has now managed to bond PDMS (polydimethylsiloxane), a soft plastic, with PEEK (polyether ether ketone), a highly stable plastic. "Through a relatively simple coating method, we were able to create a polymer composite that combines the properties of both substances in an ideal way," explains Leonard Siebert, doctoral researcher in the "Functional Nanomaterials" working group at CAU. In doing so, the surfaces of the two materials are mechanically interlocked with each other.
Through this bonding, the blood-repellent PDMS plastic became robust enough to even withstand strong pressure loads, such as those that occur in a heart valve, which is constantly opening and closing. Initial laboratory tests at the Department of Cardiac and Vascular Surgery at the University Medical Center Schleswig-Holstein (Lübeck campus) confirmed that there is significantly less blood platelet adhesion on the new composite material than on conventional materials such as titanium or diamond-like carbon layers, which are already being used for artificial heart valves. The research team has presented how they used the purely mechanical procedure to permanently bond non-adhesive plastics for the first time in the journal Nanoscale Horizons.