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