Imbibition is a physical process. It is a process in which solid or semisolid organic compounds draw water from their surrounding and swell up but do not dissolve in water. The chemicals which show this property are called inhibitants. These substances are generally hydrophilic in nature. Due to the attraction between the molecules of hydrophilic substances and water molecules, plant cell wall, seeds and wood etc. draw water and swell up. The pressure developed due to imbibition is called imbibition pressure (IP). Imbibition pressure is equal to osmotic pressure. It is an exothermic process.
Examples:
- The wooden doors and windows swell during rainy season due to this process.
- Seeds swell up due to imbibition of water.
- In the epiphytes, the hygroscopic nature of roots draws water by this process.
- In many dry fruits and sporangia, dehiscence is by this process.
- The imbibition pressure has been used to break large-sized rocks.
