Masks can be used to form a pattern of {HEAD ~ crosslinked and non crosslinked regions} on {TAIL ~ a surface} 
Masks can be used to form a pattern of { HEAD ~ crosslinked and non crosslinked regions } on { TAIL ~ a surface }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL