The Cloud Points

The Cloud Point

Nonionic surfactants become water soluble by the hydration of ether oxygens of the polyoxyethylene group. The longer chain of ethylene oxides containing ether oxygens is, the more hydration, and consequently, the more solubility. An increase in temperature causes the cleavage of the hydrogen bond between the ether oxygen of the ethylene oxide group and the hydrated hydrogen to the ether oxygen.

The depletion of water from nonionics results in the decreases of the water solubility of nonionics. The water depleted nonionic surfactant solution, therefore, becomes turbid and seperates into two phases including a insoluble hydrophobic precipitate. This sudden onsetting of turbidity of a nonionic surfactant solution when the temperature is raised is called the "cloud point". In general, nonionics having a longer polyoxyethylene chain consequently have a higer cloud point, meaning a greater capacity to hydrate.

Any kind of opinions and questions are welcome to E-mail.