Preferably, {HEAD ~ the polymer} has a molecular weight in {TAIL ~ the range} of 100 Da to 800 kDa 
Preferably , { HEAD ~ the polymer } has a molecular weight in { TAIL ~ the range } of 100 Da to 800 kDa
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH