Question

Would a non-polar liquid, such as gasoline, be more or less likely to bead up on a waxy polar surface?

Answer 1

Short answer: Less likely to bead on a waxy (non‑polar) surface; more likely to bead on a polar (high‑surface‑energy) surface.

Why: wetting is controlled by the balance of cohesive forces in the liquid vs adhesive forces between liquid and solid. "Like dissolves like" — nonpolar liquids (gasoline) interact well with nonpolar, low‑energy solids (wax), so they wet and spread (low contact angle). On a polar, high‑energy surface the adhesive interactions are poor, so the liquid minimizes contact area and beads up (high contact angle).

(Young’s equation summarizes this: cosθ = (γ_sv − γ_sl)/γ_lv — if solid–liquid affinity is low, θ is large.)

Caveats: surface roughness, contamination, and chemical compatibility (e.g., gasoline may partially dissolve or swell some waxes) can change the behavior.