Donut-like Molecules Aren't Just for Breakfast

A technique to create self-assembling organic nanotubes, cylindrical stacks of donut-like molecules, was developed through a collaborative effort between NSF-funded researchers from the State University of New York at Buffalo and teams from the University of Nebraska-Lincoln and Shanghai Jiaotong University and Beijing Normal University in China. The pores inside the nanotubes do not deform and may be fine tuned to repel salt, ions or water.

The availability of these structurally simple, synthetic nanopores with adjustable diameters could carve a new path for fabrication of highly efficient, practical membranes for applications ranging from water purification to molecular separations.

Organic nanotubes with non-deformable pores of precisely controlled diameters are rare. The great potential of this technique lies in its ability to control or tune the size and function of a sub-nanometer pore. Channels of reduced diameters may completely reject metal ions while still allowing water to pass through. Introducing additional chemistry into the pores could overcome the last major hurdle in developing artificial membranes that rival their natural counterparts.

The pores demonstrate very efficient water transport and remarkably high regulation of ion movement that are unprecedented for a synthetic pore. Currently only biological nanostructures can achieve these feats. This study has laid a foundation for developing synthetic, robust nanostructure systems.