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The challenge

Nanopores – in other words nanoscale holes in the nanometre (10-9 m) size range – significantly determine the properties of materials. For chemists such as Annette Andrieu Brunsen, the chemical-physical properties of these pores and the characteristics of the surrounding material play a decisive role in their research. A decisive contribution to today's research into nanopores was made by the development of electron microscopy in the 1970s, which made it possible to visualise these structures. In today's technical applications of nanopores, e.g. in desalination plants, porous ceramic materials are used which enable the separation of substances due to their size and interactions with the material itself. Improving the selectivity of these pores as well as reducing the variation of column properties in the manufacturing process are, for example, the subject of current research..

From the lecture

Applications for nanopores are to be found in many areas, for example in water management. Scientists are researching how selectivity can be improved through the development of new pore properties and how recycling measures, such as the selective recovery of metal ions and other substances from wastewater, can be realised. Porous membranes could act as a material for energy storage based on the principle of osmosis, in which osmotically generated pressure is converted to generate energy. Today, individual nanopores are already being used commercially for DNA sequencing. Here, ions move through the pore in an electric field; if a DNA strand is present, the ion current is reduced. The specific characteristics of nanoporous materials are crucial for all applications, e.g. the size of the specific surface area. Typically, several hundred square metres of surface area are achieved per gram of material. This is important for catalytic functions, for example, but also in drug delivery systems for medical applications.

Perspectives

Current research efforts in the field of nanopore design are focussing, among other things, on controlling the placement of molecular function and structure across all length scales, on improving selectivity, or on developing completely new separation concepts using temporal switchability. Research in this field has shown possible theoretical approaches, but these are still difficult to realise experimentally. There have been experimental successes, for example, through the use of controlled polymerisation of zwitterionic polymers and 3D printing of porous materials. The founding of the start-up company CeraSleeve, which specialises in sustainable, wet-strength paper coatings and combines paper and nanoscale porous coatings, is another success story.