The first surface 930A is exposed to {HEAD ~ the moisture} donating {TAIL ~ fluid}, while the second surface 930B is exposed to the moisture accepting fluid 
donating
The first surface 930A is exposed to { HEAD ~ the moisture } donating { TAIL ~ fluid } , while the second surface 930B is exposed to the moisture accepting fluid
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH