Free-standing carbon membranes that are a millionth of a millimetre thin: these are a special research field of Professor Dr. Armin Gölzhäuser from Bielefeld University and his research group. The nanomembranes can serve as ultrafine filters and as a protective layer. The Bielefeld physicists have registered several patents for manufacturing such molecular foils. In their research, they are analysing which properties the nanomembranes possess – as a basis for future applications. In a new film produced by Bielefeld University’s ‘research_tv’, Armin Gölzhäuser explains what makes the membranes such multi-talents and assesses how significant they may become for the purification of water.