Facile Method To Efficiently Fabricate Large-Size Mesoporous Organosilica Nanosheets with Uniform Tunable Pore Size for Robust Separation Membranes

Mesoporous thin films have been attracting considerable attention due to their potential application in membrane separation technology. However, how to prepare robust mesoporous silica films on a large scale using simple method still remains a great challenge. In this paper, for the first time, we report a facile and novel approach to fabricate layered mesoporous silica thin membrane using mesoporous organosilica nanosheets (mOSiO₂ NSs) as the building block, which are prepared by combining template growth and selective etching. Transmission electron microscopy characterization displays that the resulting mOSiO₂ NSs possess a large aspect ratio, a controllable thickness (16–27 nm), and a uniform tunable pore size (4–24 nm) by adjusting the reaction conditions. Owing to the large lateral dimension of the nanosheets, the as-prepared mOSiO₂ NSs can be easily stacked into a highly packed and oriented membrane via the vacuum filtration. The results show that the nanofilter device based on such mOSiO₂ NSs can successfully separate ovalbumin/cytochrome c (OVA/cyt c) or Ag/Au nanoparticles with different sizes, which provides a new strategy for nanosize separation.