Novel composite membrane

Abstract

A composite membrane is provided having a first layer and a second layer, the first layer comprising an alginic acid or a salt of alginic acid, or a salt of a derivative of an alginic acid, and the second layer comprising a non-porous polymer with at least one hydrophilic functional group and adapted to provide mechanical support and reinforcement of the first layer. The second layer is selectively water permeable and can comprise water insoluble polymers such as chitosan, chitosan derivatives and cellulose derivatives. The second layer can also comprise water soluble polymers so long as such polymers are adequately crosslinked. Where the second layer comprises chitosan, each of the alginic acid or the salt of an alginic acid or the salt of a derivative of an alginic acid of the first layer and the chitosan of the second layer can be crosslinked separately by immersing in a formaldehyde solution. The thickness of the first layer is from about 0.5 microns to about 20 microns. The thickness of the second layer is from about 1.0 microns to about 40 microns. The ratio of the thickness of the first layer to the second layer is from about 1:1 to 1:5.

Dependencies are inferred from the claim text.