{TAIL ~ sulfonated poly} coated on the polymer substrate membrane to form {HEAD ~ an ion selective membrane}, 
{ TAIL ~ sulfonated poly } coated on the polymer substrate membrane to form { HEAD ~ an ion selective membrane } ,
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH