Tannic acid (TA)-aminopropyltriethoxysilane (APTES) coating has

excellent hydrophilicity, and can be applied to a variety of materials. But it

has poor stability in the air. To improve its stability, we have developed

TA-APTES-Fe(III) coating in our previous work, but there are still some

problems remained such as tedious steps, and undesirable anti-crude

oil-adhesion performance, etc. Besides, both TA-APTES and TA-APTES-Fe(III)

coating cannot realize the hydrophilic modification of the inner surfaces of

porous polypropylene (PP) membrane. To solve the above mentioned problems, we

developed superhydrophilic and stable TA-APTES- tetraethylorthosilicate (TEOS)

coating via one-step process in this study. The new coating can realize the

superhydrophilic modification of the inner surfaces of porous PP membrane, and

endows the PP membrane with good water permeability, which cannot be realized

by our previously reported TA-APTES and TA-APTES-Fe(III) coating. Besides, the

stability of the coating is greatly improved by introducing stable alcoholic

hydroxyl groups derived from TEOS, and the resultant modified membrane can keep

superhydrophilic (CA about 0°) and underwater superhydrophobic (underwater oil

CA above 150°) even after being stored in air for more than 6 months,

ultrasonic treatment for 10 min, or being rinsed by water for 24h (3000r/min),

exhibiting outstanding stability. More importantly, the crude oil adhesion

force of the new coating is as low as 4 μN even under the preload force of

300μN, showing excellent anti-crude oil-adhesion property. The PP membrane

modified by the new coating possesses ultrahigh water flux (10384 L m-2

h-1 bar-1) and can realize highly efficient separation of

oil-in-water emulsion (above 99%). This work is expected to accelerate the

practical application of TA-APTES coating.