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