As part of the Flex Function 2 Sustain project, it was possible to coat a flat membrane with a thin, homogeneous gold film using a roll-to-roll process (R2R) for the first time.
By controlling the mechanical load when winding the membrane roll and by limiting the heat input, the formation of wrinkles could be greatly reduced. The wrinkles visible during the tests do not influence the microscopic properties of the membranes. In the project, polymer membranes of various materials, thicknesses and manufacturing processes (track pore membranes and membranes from phase inversion processes) are coated in order to develop a widely applicable manufacturing process.
The R2R coating process is a milestone for the further industrialization of switchable membrane products and an important prerequisite for pleated filter elements (capsules) with membrane areas of a few hundred cm2.
The next project milestone is to optimize the R2R process regarding the quality of the gold layer and the deposition rates. i.e., the process costs. Consequently, the interconnection technology for small membrane filter elements, particularly the electrical connection of the membrane to the voltage source, is going to be advanced and optimized. Compared with standard processes, electrically switchable membrane technology or membrane chromatography enables the use of smaller quantities of media such as buffer solutions, electrolyte solutions or acids for bio separation, e.g., purification of antibodies. As a result, the target molecules to be separated (such as antibodies), but also the stationary phase, are less stressed. At the same time, the advantage of high flow rates compared to column separation processes is maintained