  Charged porous polymer membranes (CPMs) emerging as a multifunctional
platform for diverse applications in chemistry, materials science, and
biomedicine have been attracting widespread attention. Fabrication of CPMs in a
controllable manner is of particular significance for optimizing their function
and maximizing practical values. Herein, we report the fabrication of CPMs
exclusively from poly(ionic liquid)s (PILs), and their pore size and
wettability were precisely tailored by rational choice of the counteranions.
Specifically, stepwise subtle increase in hydrophobicity of the counteranions
by extending the length of fluorinated alkyl substituents, i.e. from
bis(trifluoromethane sulfonyl)imide (Tf2N) to bis(pentafluoroethane
sulfonyl)imide (Pf2N) and bis(heptafluoropropane sulfonyl)imide (Hf2N),
decreases the average pore size gradually from 1546 nm to 157 nm and 77 nm,
respectively. Meanwhile, their corresponding water contact angles increased
from 90 degree to 102 degree and 120o. The exquisite control over the porous
architectures and surface wettability of CPMs by systematic variation of the
anion's hydrophobicity provides a solid proof of the impact of the PIL anions
on CPMs' structure.
