Preparation method of ultrathin silicon-based alcohol water separation film with thickness smaller than 50 nm

Abstract

The invention belongs to the field of film material preparation, and particularly relates to a preparation method of an ultrathin silicon-based alcohol water separation film with thickness smaller than 50 nm. A common dip-coating method in a current film preparation process has the problems that the thickness of a separating layer is larger than 300 nm, flux is small and the preparation process cannot be regulated and controlled accurately, and even the thickness layer of the separating film prepared with a spin-coating method, an infriction method and the like cannot be 200 nm or smaller. Aiming at the problems, organic silica sol with low concentration is atomized by ultrasonic waves, sol is enabled to be dispersed into numerous tiny droplets, the atomized sol is deposited on a porous polymer support by carrier gas purging, finally, drying is performed, and the ultrathin silicon-based alcohol water separation film with the separating film thickness smaller than 50 nm is prepared.

Description

technical field [0001] The invention belongs to the field of separation membrane preparation, and in particular relates to a preparation method of an ultra-thin silicon-based alcohol-water separation membrane with a thickness less than 50 nm. Background technique [0002] The sol-gel method can precisely control the pore size and pore structure, and can directly prepare a microporous inorganic membrane on the support (or transition layer). Like the traditional inorganic silicon film, the organic silicon film is generally prepared by the sol-gel method, and the coating methods usually include the dipping and pulling method, the spin coating method and the wiping method. [0003] The commonly used dipping and pulling method is to immerse one side of the support in the pre-prepared sol, and after dipping for a period of time, the support is pulled out of the sol at a certain speed, and then the solvent is removed by calcination and dehydrated. The condensation reaction thus fo...

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Problems solved by technology

[0004] The dipping and pulling method has problems such as large thickness of the separation layer (>300nm), small flux, and inability to precisely control the preparation process. Even if the separation layer is prepared by spin coating, wiping coating, etc., the thickness of the separation layer is difficult to reach below 200nm.

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