Amphiphile Self-Assembly

Hydrophobic effect and micelle formation

Molecules: 80

Temperature: 0.5

Hydrophobicity: 1.5

Tail length: 3

Hydrophilic head

Hydrophobic tail

Micelle core

Amphiphilic molecules (like soap or phospholipids) have a water-loving (hydrophilic) head and a water-fearing (hydrophobic) tail. Above the critical micelle concentration (CMC), they spontaneously self-assemble into spherical micelles — the tails huddle inside, heads face water. This is driven by the hydrophobic effect: water gains entropy by excluding nonpolar groups. The CMC decreases exponentially with tail length (Tanford's rule: log CMC ≈ A − B·n).