R6, R8, R12, and R13 are independently selected from {HEAD ~ the group} consisting of hydrogen, alkyl, alkoxyalkyl, polyfluoroalkyl, hydroxyalkyl, {TAIL ~ polyhydroxyalkyl}, aralkyl, R9, —R15 and —R9 
consisting of
R6 , R8 , R12 , and R13 are independently selected from { HEAD ~ the group } consisting of hydrogen , alkyl , alkoxyalkyl , polyfluoroalkyl , hydroxyalkyl , { TAIL ~ polyhydroxyalkyl } , aralkyl , R9 , — R15 and — R9
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH