Why food sticks to nonstick frying pans

Foods will sometimes get stuck to a heated surface, even if oil or a nonstick frying pan is used. Scientists have investigated the fluid properties of oil on a flat surface and their work shows convection may be to blame. When the pan is heated from below, a temperature gradient is established in the oil film, as well as a surface tension gradient. This gradient sets up a type of convection known as thermocapillary convection.