{TAIL ~ and 0.93 wt %} of {HEAD ~ 7 mercaptopropyltrimethoxysilane}; and 
{ TAIL ~ and 0.93 wt % } of { HEAD ~ 7 mercaptopropyltrimethoxysilane } ; and
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH