Electrospun cellulose nanofibers for superhydrophobic and oleophobic membranes

In this study, we produced a super hydrophobic and oleophobic cellulose nanofiber membrane by reducing the surface energy of the membrane through the attachment of SiNPs and chemical vapor deposition of fluoroalkylsilane. SiNPs were growing on top of the fibers by using in situ sol-gel approach. SiNPs cellulose nanofiber composed mat was coated with fluoroalkylsilane by CVD. The grafted SiNPs on cellulose nanofiber were then coated with fluoroalkylsilane to lower the surface energy of the nanofiber membrane. The fabricated membrane showed excellent hydrophobicity and oleophobicity (also known as omniphobic), as demonstrated by its wetting resistance to water, ethanol, surfactant, and mineral oil. The prepared omniphobic membrane was used in direct contact membrane distillation (DCMD) to separate water from saline feed solutions containing low surface tension substances. The fabricated omniphobic cellulose nanofiber membrane showed very high resistance against wetting and it exhibited a stable water vapor flux performance for 10 h of operation. Moreover, the performance of the fabricated omniphobic cellulose nanofiber membrane was compared to commercial hydrophobic PVDF and PTFE membranes against saline feed solutions containing low surface tension substances.