Reversible nanovalves in inorganic materials

This article describes recent developments in the design, fabrication and investigation of reversible nanovalves prepared in inorganic nanoporous materials such as glass, silicon nitride, mesoporous silica, anodized alumina and silica colloidal crystals. Their surfaces have been modified with pH-, temperature- and light-responsive molecules, as well as molecules that can undergo redox reactions and bind small molecules. This surface modification allows reversibly opening and closing of the nanovalves to the transport of ions based on electrostatic interactions, and to the transport of molecules based on mechanically gating the nanopores.