Tiny Solution Improves Water Filtration

Researchers at the University at Buffalo and Colorado State University have created polymeric materials that form membranes with 55 nanometer nanopores, just the right size for water molecules to slip through, but too small for bacteria. The openings are almost twice the size of what was previously possible.

A major bottleneck to advancing filtration membranes for water purification is the size of the pores, since they restrict flow of the water. The new materials circumvent this problem by not only enlarging the pore sizes, but also by coating the inside of each pore with polymers that interact favorably with water.

Javid Rzayev and his colleagues have accomplished this by designing new kinds of polymers which they call bottlebrush block copolymers. The polymers consist of very long molecules joined together--each one having a dense array of different short molecules that jut out across its length like the bristles in a brush. When these highly complex polymers are made into thin films, the bristles come together to form wide columns that extend across the thickness of the films. The columns are then etched away leaving behind wide-diameter nanopores.

To learn more, visit the University of Buffalo site: www.buffalo.edu/news/12604