Significance
Membranes with asymmetric wettability (Janus membranes) bring a new
feature to the field of membrane science. Here, we developed a scalable
and high-precision method for imparting asymmetric wettability to the
porous substrates. The thickness and surface topography of the
integrated domains are tailored based on the requirements of a specific
application. The developed method is scalable and is performed in a
roll-to-roll manner.