PFAS‑free sol‑gel hybrid coatings for sustainable cookware, glass and food‑packaging equipment.

The pervasive use of per‑ and poly‑fluoroalkyl substances (PFAS) in non‑stick, anti‑soiling and water‑repellent coatings has generated growing concerns over their toxicity, persistence and bio‑accumulation. In response, the TORNADO and PROPLANET projects have pursued sol‑gel‑based, PFAS‑free hybrid coatings that simultaneously meet the demanding functional, mechanical and aesthetic requirements of kitchenware, low‑maintenance glass and food‑packaging machinery.

In the TORNADO line, a ceramic–organic network is generated by hydrolysis and condensation of metal alkoxides combined with siloxane organofunctional groups and silicon oils. Optimised precursor ratios yield a two‑layer system (base‑coat + top‑coat) that can be sprayed onto aluminium pans. The resulting film is homogeneous, hydro‑ and oleo‑phobic (SFE ≈ 25 mN/m), scratch‑, impact‑ and abrasion‑resistant, corrosion‑proof and stable at cooking temperatures up to 300 °C.

Parallel work in PROPLANET has produced two sol‑gel‑based families of coatings. (i) Transparent hybrid films for glass provide durable hydrophobic and anti‑soiling performance, suitable for automotive windows and shower doors. (ii) PFAS‑free, functionalised hybrids for food‑packaging machines deliver non‑stick, anti‑wear behaviour together with high‑temperature resilience. Systematic screening of chemistries and functional groups, together with contact‑angle measurements (water/hexadecane) and standard mechanical tests, confirms omniphobic surface free energies and long‑term durability under service‑relevant conditions.

These results demonstrate that sol‑gel chemistry enables the design of environmentally benign, high‑performance coatings, offering a viable pathway to replace PFAS in diverse consumer and industrial applications while supporting circular‑economy value chains.