Nanomembranes can be defined as filters that separate liquids and gases at the molecular level.
Biomimetics and Nanomembranes
Although nanotechnology is a relatively new science, the idea of filtering at the nanoscale using a membrane is nothing new. It is a biomimetic process copied directly from nature. Living cells use a form of nanomembrane to function. These processes include the transfer of salts from blood and the transport of oxygen to and carbon dioxide from cells.
Nanomembranes are commonly made from organic polymer based nanocomposites with a thickness less than 100nm. Such nanomembranes include organic polymers combined with a mesh of silica nanoparticles. The size of the holes in the mesh restricts or allows the passage of different sized molecules.
Applications for nanomembranes include :
· Desalination of sea water
· Purification of polluted water
· Removal of carbon dioxide and other pollutants from exhaust gases
· Sensors in MEMS
Nanomembranes are commonly fabricated using Layer-by-Layer (LbL) assembly methods. This method give precise control over the in plane composition of the membrane and allows for the addition of a range of components to be added to the membrane. These components include nanoparticles and nanotubes that can tailor the mechanical, optical and electronic properties of the nanomembrane.