Hydrophilic-to-hydrophobic conversion of polyamide 6-based mat via polyvinylidene fluoride nanofiber integration with enhanced oil-water separation

Abstract

This study presents a unique technique for fabricating a highly effective hydrophobic polyamide 6 (PA6)-based nonwoven mat with remarkable performance in hydrophobicity and oil-water separation. Utilizing a ternary blend system of polypropylene (PP)/PA6/polyvinylidene fluoride (PVDF) based on Harkin's theory and employing an in-situ fibrillation process, a distinctive micro-nano hierarchical structure is achieved. The removal of the PP matrix results in a nonwoven mat composed of bimodal PA6 microfibers surrounded by PVDF nanofibers. Water contact angle measurements revealed micro-nano hierarchical structure in the mat-induced hydrophobicity on the intrinsically hydrophilic PA6. Further optimization of the PP removal process enhances the hydrophobicity of the micro-nano fibrillar structure. The mat also demonstrates outstanding efficiency in separating oil and water, with an impressive oil-water separation efficiency of up to 97.4%. This scalable fabrication technique opens significant opportunities for the utilization of hydrophobic PA6 nonwoven mats in diverse industries, including textiles and other sectors where water repellency is crucial. Furthermore, these hydrophobic PA6 nonwoven mats hold great potential for sustainable applications in environmental settings, addressing the growing need for both hydrophobicity and efficient oil-water separation solutions.