Medical technology in particular faces major challenges in the surface treatment of products, as this often requires very elaborate cleaning methods or extremely harmful chemical treatments. Special materials are often processed in these products, with each type of material presenting its own individual challenges when it comes to surface preparation for printing or bonding. 

Customers often have a variety of requirements for surface preparation, treatment and modification for sensitive and vital applications. In addition, medical devices often use special materials such as PTFE, FEP and polyamide, which are difficult to treat. Conventional methods are usually expensive, harmful and very limited in their application range. Here Plasmatreat offers sustainable and user-friendly solutions for providing clean and functionalized surfaces of all materials. As the technological leader in the field of plasma applications Plasmatreat has set itself the goal of replacing costly and environmentally harmful processes. As a manufacturer and supplier of plasma systems as well as a service provider operating worldwide in surface technology the company develops and supplies several different treatment processes depending on the complexity, size and number of products to be processed.  

Essentially, there are two processes. On the one side, the Aurora systems which operate with low-pressure plasma and enable surface pretreatment of a single or a large number of products in a batch process. In this case, a homogeneous treatment of the entire surface takes place in a low-pressure chamber. On the other side, the Openair-Plasma process allows the treatment of a product locally, fast and continuously within the production line under atmospheric pressure. Both plasma processes use process gases that are converted into an excited state. The excited molecules, ions and free electrons interact on contact with surfaces such as rubber, metal, plastic or ceramic and change the surface chemistry.  

The manufacturing of catheters is an example of the possibilities that plasma treatment offers, because the fluoropolymers often used are largely resistant to conventional surface treatment methods. Therefore, they normally require extreme chemical treatment, such as sodium etching. This method is environmentally harmful and expensive way of preparing a bondable fluoropolymer surface. It also has other disadvantages, such as the application of an additional primer or bonding agent and discoloration of the material, which is problematic for maintaining product aesthetics. In contrast, plasma pretreatment gently and reliably removes parting agents and organic contaminants from surfaces and thus subjects them to ultra-fine cleaning. During the same process step, plasma activation can also be carried out, which enables adhesives and coatings to adhere later. With the Aurora systems, a so-called plasma etching (plasma etching) can be carried out on PTFE in order to remove all contamination from the surface in a targeted manner using defined process gases at the nanometer level. In a next step, the removal of functional layers allows the PTFE to be optimally prepared for permanent connections within a certain time window. Since this process is carried out under vacuum and with neutral gases, it is much more environmentally friendly and also much easier to handle. 

Another area of application is illustrated by a recent study. In this study a comparison was made between the adhesive bonding of the fluoroplastics FEP and PFA after plasma modification and after tetraetching. As expected, at the beginning almost no adhesion was achieved on an untreated surface. Both the tetra-etched and the plasma-treated samples showed a significant improvement in adhesion strength. The introduction of cost-effective plasma processes using a low-pressure or open-air plasma system, depending on the application, has largely eliminated the use of harmful chemicals, which has significantly reduced the amount of toxic process waste. 

Besides the preparation of surfaces in product manufacture, the same process attributes of plasma surface treatment can also be used in other medical technology applications. A very current topic is the treatment of test kits for laboratory analyses as used for the detection of Covid-19 disease and other detection methods. The demands on the efficiency of these test processes are constantly increasing, e.g. to use as little analysis substrate as possible in order to minimize the costs for the individual tests. This can be achieved by a hydrophobic surface coating, which is applied specifically in the area of the test which comes into contact with the liquid. The super-hydrophobic coating, which is applied locally by an Openair-Plasma system meets this requirement. These coatings, which are only nanometers thick, also fulfill the highest analytical demands with regard to optical transparency and sealing.  

In summary, the plasma processes have their individual strengths, which can be used in a specific way depending on the application: As a dry cleaning technology, plasma processes replace costly manual or wet-chemical / solvent-based cleaning processes, thereby meeting increasing demands for VOC-reduced production. At the same time, they reduce cycle times. The surface properties can be customized for different purposes, such as adhesive, oleophobic/oleophilic, hydrophobic/hydrophilic and other desired functionalities. 

Medical Disinfection