In one aspect of the present invention, {TAIL ~ the polymer hydrogel} is characterized by a repeating unit having {HEAD ~ the formula} 
In one aspect of the present invention , { TAIL ~ the polymer hydrogel } is characterized by a repeating unit having { HEAD ~ the formula }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD