Role of Extruded Sheet Morphology in Phase Separation and Final Morphology of Superhydrophobic Polypropylene

In this study, we prepared polypropylene sheets with a superhydrophobic surface from extruded sheets with a phase separation method. We investigated the influence of extrusion parameters on the morphological properties of the polypropylene sheet and found that two significantly different structures can be formed in the cross-section of the sheet when the cooling temperature was varied. The effect of the morphology of the extruded material was studied on phase separation and through that on the surface structure that formed. The created morphology of the extruded sheet plays a significant role in the procedure of the phase separation method and less in surface wettability. We also included a polypropylene blend and nucleated polypropylene in this study to investigate their role in surface morphological changes and indirectly on wetting behavior. Surfaces have become superhydrophobic with an increased water contact angle from 102° to 150° and contact angle hysteresis below 10°. For nucleated polypropylene samples, we achieved remarkably good results (a water contact angle of 158°). The morphological and wettability behavior of the surfaces were investigated with a polarized optical microscope and water contact angle measurements, and scanning electron microscopy, respectively.