0 to about 95% by weight of a structural unit represented by the formula ##STR5## wherein X2 is hydrogen, fluorine or methyl and {HEAD ~ X3} is {TAIL ~ C1 C10 alkyl group} or C2 C10 fluoroalkyl group ; and 
0 to about 95 % by weight of a structural unit represented by the formula # # STR5 # # wherein X2 is hydrogen , fluorine or methyl and { HEAD ~ X3 } is { TAIL ~ C1 C10 alkyl group } or C2 C10 fluoroalkyl group ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH