Review: Ultrathin Silica Membranes with Highly Ordered and Perpendicular Nanochannels for Precise and Fast Molecular Separation
Xingyu et al; Supplement
The authors of this submission to ACS Nano apply techniques for the creation of mesoporous silica thin films with vertically aligned nanochannels to create ultrathin (< 100 nm) silica membranes with ~ 2 nm nanochannels. The technique involves the growth of silica around surfactant templates followed by the removal of the surfactants. The approach for making the channels was originally developed by Teng_et al. 2012 and is illustrated in this figure …
Teng et al also demonstrated that when the silica layer was grown on ITO they could remove the membrane and capture it on another surface (transfer) by etching the ITO in nitric acid.
Xingyu et al. reproduced this material and transferred to microporous (2 um) silicon nitride membranes …
The ultrastructure of this material is impressive and something we have not achieved – a high density 13.7% porosity of very small pores.
The authors then proceed to do separation experiments with very small molecules using a system that looks similar to our earliest experiments, but with the addition of electrodes for electrochemical detection of molecules.
In low salts they demonstrate, remarkable discrimination of fluorescent molecules by size.
Then they examine the impact of varying salt concentration …
Finally they look at the kinetics
