Phase inversion (chemistry) Phase inversion (chemistry) Phase inversion is a chemical phenomenon exploited in the fabrication of artificial membranes. It is performed by removing the solvent from a liquid-polymer solution, leaving a porous, solid membrane. Phase inversion is a common method to form filtration membranes, which are typically formed using artificial polymers. The method of phase inversion is highly dependent on the type of polymer used and the solvent used to dissolve the polymer. Phase inversion can be carried out through one of four typical methods: The rate at which phase inversion occurs and the characteristics of the resulting membrane are dependent on
Amount of substance especially the early metallurgists, probably had some notion of amount of substance, but there are no surviving records of any generalization of the idea beyond a set of recipes. In 1758, Mikhail Lomonosov questioned the idea that mass was the only measure of the quantity of matter, but he did so only in relation to his theories on gravitation. The development of the concept of amount of substance was coincidental with, and vital to, the birth of modern chemistry. Amount of substance Amount of substance is a standard-defined quantity that measures the size of an ensemble of particles, such as