Silicone / siloxanes (vs silica)
Quick answer: Silicones/siloxanes are man-made oils and polymers used for slickness and water behaviour; silica (SiO₂) is an inorganic oxide that forms the glass-like ceramic network in coatings. They are different chemistries and do different jobs.
What it means
Silicones (polysiloxanes such as PDMS) are flexible organosilicon polymers used as lubricants, gloss enhancers and hydrophobics in detailing products. Siloxanes can also be functional molecules (silanes) that bond to paint and change surface energy. Silica is silicon dioxide, an inorganic Si–O–Si network – the ceramic backbone many coatings cure into. Marketing often mixes the terms, but silicone ≠ silica.
Why it matters
- Bonding & prep: silicone residues can interfere with coating or paint adhesion if not removed – use proper panel wipe before protection.
- Finish & feel: silicones add slickness and gloss in QDs, dressings and toppers; silica provides the durable ceramic film.
- Bodyshop safety: airborne silicone can cause “fisheyes” in respray work; bodyshops prefer silicone-free prep chemicals.
- Label clarity: “Contains SiO₂” is not the same as “contains silicone”. Some coatings include siloxane groups as part of their chemistry without being “silicone oils”.
Where you’ll see it
Quick detailers, tyre/interior dressings, shampoos with gloss enhancers, coating toppers and manufacturer tech sheets that quote “% SiO₂” or mention silane/siloxane modification.
Context
Car Paint Protection; Ceramic coatings; Bodyshop prep
Common mistakes
- Confusing silicone with silica and assuming they’re interchangeable.
- Thinking “silicone-free” means “no SiO₂” – silica is not silicone.
- Believing a product with silicones cannot be coated later – correct decontamination and panel wipe remove residues.
- Assuming “% SiO₂” alone predicts performance – formulation, prep and curing are equally important.
Written by Danny Argent. Last updated 11/11/2025 13:57