Most preferably, {TAIL ~ the polymer} has a molecular weight in the range of {HEAD ~ 15 kDa} to 40 kDa 
Most preferably , { TAIL ~ the polymer } has a molecular weight in the range of { HEAD ~ 15 kDa } to 40 kDa
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH