Wettability study of porous pattern membranes inspired by banana leaf

Janus wettability, characterized by the coexisting hydrophilic and hydrophobic domains on single material is gaining considerable attention owing to its potential to alter solid-liquid interactions and subsequent interesting outcomes. Banana leaf is a classic example of this with adaxial side exhibiting stronger wettability characetristics compared to the abaxial side owing to structural differences in terms of nanopillars dimensions. The leafs are observed to be composed of longitudinal patterns of two different length scales along with intermittent nanopillars present in between in random orientation. Present work attempts to prepare a porous replica of banana leaf pattern (both abaxial and adaxial) with cellulose acetate as base polymer using nonsolvent induced phase separation process and study the effect on surface wettability. The pattern formation has been confirmed from the FESEM analysis both for the substrate and the replica, with nanopillars replicating as nanodents. The additional effect of chemical composition of leaf surface on the wettability is explored. Such porous patterned membranes can be tailor-made to prepare biological scaffolds with desirable wettability properties and also find applications in water treatment membranes.