Crosslinked zwitterionic hydrogels

A crosslinked hydrogel, comprising a crosslinked polymer having repeating units and a plurality of crosslinks, wherein each crosslink is represented by the formula:

• wherein
• R1 and R2 are independently selected from the group consisting of hydrogen, fluorine, trifluoromethyl, C1-C6 alkyl, and C6-C12 aryl groups;
• R3 is selected from the group consisting of C1-C6 alkyl, C6-C12 aryl, CH2═C(R1)-L1-, CH2═C(R2)-L2-, or R3 is the residual portion of a third crosslink, -L1-CR1—CH2— or -L2-CR2—CH2—;
• L1 and L2 are independently selected from the group consisting of —C(═O)O—(CH2)n— and —C(═O)NH—(CH2)n—, wherein n is an integer from 1 to 20;
• L3 is —(CH2)n—, where n is an integer from 1 to 20;
• A1 is C, S, SO, P, or PO;
• x is an integer from about 5 to about 10,000;
• X− is the counter ion associated with the N+ cationic center;
• and
• M+is a counterion associated with the (A=O)O− anionic center.