The polyethylene glycol diamine has {TAIL ~ the formula} NH2 x CH2 CH2 NH2, where x ranges from 2 to 6, and at least one of the dicarboxylic acids is {HEAD ~ an aromatic discarboxylic acid} 
The polyethylene glycol diamine has { TAIL ~ the formula } NH2 x CH2 CH2 NH2 , where x ranges from 2 to 6 , and at least one of the dicarboxylic acids is { HEAD ~ an aromatic discarboxylic acid }
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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD