Nanocellulose Coatings for Surgical Face Masks.

Area of Science:

• Materials Science
• Biomaterials Engineering
• Surface Chemistry

Background:

• Polypropylene (PP) nonwovens are crucial for surgical mask filtration but their hydrophobic nature hinders functionalization.
• Improving mechanical filtration and pore size control requires modifying the inert surface of PP nonwovens.

Purpose of the Study:

• To develop nanocellulose coatings from sugarcane debris for modifying PP nonwoven surfaces.
• To evaluate the surface properties, adhesion, and biocompatibility of these nanocellulose coatings.

Main Methods:

• Sugarcane cellulose was processed into cellulose nanofibres (CNFs), TEMPO-oxidised nanofibres (TCNFs), and cationic nanofibres (CCNFs).
• Nanofibres were characterized for structure, thermal stability, surface charge (ζ), and wettability.
• PP nonwovens were dip-coated with nanocelluloses, with and without ethanol pretreatment, and analyzed for coating uniformity and adhesion under humidity.

Main Results:

• TCNF and CCNF provided uniform coatings on PP nonwovens at 1 wt%, with CCNF inverting PP's surface charge and maintaining it under humidity.
• Ethanol pretreatment enhanced CCNF adhesion and preserved a continuous nanoporous film under humid conditions.
• Coated and uncoated nonwovens showed no detectable cytotoxicity.

Conclusions:

• Sugarcane-derived nanocellulose, specifically TCNF and CCNF, are effective biocompatible coatings for PP mask nonwovens.
• These coatings modify surface properties and enhance adhesion without compromising material integrity or safety.
• The developed coatings show potential for improving surgical mask filtration performance.