Aqueous solution method for forming a hydrogel composition

Aqueous solution method for forming a hydrogel composition, comprising:

• mixing an aqueous solution of a vinylphosphonic acid having chemical formula I:
• and an aqueous solution of bis[2-(methyacryloyloxy)ethyl] phosphate (BMEP) to form an aqueous mixture;
• and
• initiating a polymerization reaction in the aqueous mixture by adding an initiator selected from the group consisting of an azo compound, a ketone, and an organic peroxide to form a polymerization reaction mixture,
• heating the polymerization reaction mixture to form the hydrogel composition, wherein the hydrogel composition comprises a cross linked polyvinyl polymer;
• wherein R1 is phosphonate;
• and R2, R3, and R4 are independently hydrogen, sulfonate, carboxylate, phosphonate, optionally substituted methyl, ethyl, propyl, optionally substituted cycloalkyl, or optionally substituted aryl or heteroaryl;
• wherein the BMEP is present in the cross linked polyvinyl polymer in an amount of about 40 mol % based on the total molar amount of the vinylphosphonic acid of formula I and the BMEP;
• and
• wherein the cross linked polyvinyl polymer consists essentially of polymerized units of the vinylphosphonic acid having chemical formula I and the BMEP.