The membrane 1 which is the polyimide from {TAIL ~ pyromellitic dianhydride} and {HEAD ~ 4,4 diaminodiphenyl ether} 
The membrane 1 which is the polyimide from { TAIL ~ pyromellitic dianhydride } and { HEAD ~ 4,4 diaminodiphenyl ether }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD