Amphiphile Bilayer Self-Assembly

Hydrophobic effect drives lipid organization — Helfrich free energy

Parameters

F_hydrophobic = -ε_h × (tail contacts)
F_steric = +ε_r/r² (head-head)
F_Helfrich = κ/2 × (c₁+c₂-c₀)²
CMC: φ* = exp(-ε_h/kT)
Order param: —
CMC: —
Amphiphiles have hydrophilic heads (circles) and hydrophobic tails (sticks). Above CMC, they spontaneously form bilayers or micelles. The hydrophobic mismatch energy drives tail burial; Helfrich elasticity resists curvature.