How do phospholipids arrange into bi-layers?

Phospholipids arrange into bilayers due to their amphipathic nature, possessing both hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails. When placed in an aqueous environment, the hydrophilic heads face outward toward the water, while the hydrophobic tails point inward, away from the water. This arrangement minimizes the exposure of the hydrophobic tails to water, creating a stable bilayer structure that forms the foundation of cell membranes. The bilayer also allows for flexibility and fluidity, essential for cellular functions.