Sulfobetaine-modified polyurethane or polyurea foam

A hydrophilic foam comprising a polymer formed from a betaine prepolymer of formula (I):

• wherein A− is an anionic functional group,
• R1, R2, and R3 are each hydrocarbon groups having from 1 to 4 carbon atoms,
• R5 is a linear or branched aliphatic hydrocarbon group having from 2 to 12 carbon atoms, or a 5- or 6-membered aliphatic or aromatic carbocyclic group having from 5 to 50 carbon atoms,
• b is an integer having a value of 1, 2, or 3, and
• c is the degree of polymerization of the betaine prepolymer, which is an integer having a value of 1-5.

A method comprising the steps of:

• (a) reacting a betaine of formula (I) with one or more polyether glycols and a polyfunctional isocyanate compound of formula (II) to provide a hydrophilic prepolymer,
• wherein R1, R2, R3, and R4 are each hydrocarbon groups having from 1 to 4 carbon atoms,
• A− is an anionic functional group, and
• X+ is a cationic atom,
• OCN—R5—(NCO)b (II)
• wherein R5 is a is a linear or branched aliphatic hydrocarbon group having from 2 to 12 carbon atoms, or a 5- or 6-membered aliphatic or aromatic carbocyclic group having from 5 to 50 carbon atoms, and
• b is an integer having a value of 1, 2, or 3;
• (b) polymerizing and foaming the hydrophilic prepolymer of step (a) to provide a hydrophilic foam.