diffuustransport

Diffusion is a fundamental process in physics and chemistry where particles spread out from an area of higher concentration to an area of lower concentration. This movement is driven by the random motion of individual particles, often referred to as Brownian motion. Over time, this random movement leads to a net flux of particles down the concentration gradient, until the concentration is uniform throughout the system.

In biological systems, diffusion plays a critical role in transporting substances across cell membranes and within cells. For example, oxygen and carbon dioxide move into and out of cells via diffusion. Nutrients and waste products can also be transported through diffusion, although for larger molecules or across longer distances, facilitated diffusion or active transport mechanisms may be employed. The rate of diffusion is influenced by factors such as temperature, the size of the particles, and the properties of the medium through which they are diffusing.

The concept of diffusion is also applied in various engineering and material science contexts. For instance, in semiconductor manufacturing, diffusion is used to introduce dopant atoms into silicon crystals. In the study of polymers, diffusion describes how solvent molecules penetrate a polymer matrix. The mathematical description of diffusion is often governed by Fick's laws, which relate the flux of particles to the concentration gradient.