Micelles are nanoscale spherical structures composed of amphiphilic molecules, which contain both hydrophobic (water-repellent) and hydrophilic (water-attracting) components. These structures form when amphiphilic molecules are introduced into an aqueous environment, leading to the self-assembly of the molecules into a spherical shape with the hydrophobic tails inward and the hydrophilic heads outward. This unique formation makes micelles ideal for various applications in drug delivery.