The catalyst solution may include a dye or other colorimetric substance for visualizing {HEAD ~ the layer} of catalyst solution on {TAIL ~ the substrate} 
on
The catalyst solution may include a dye or other colorimetric substance for visualizing { HEAD ~ the layer } of catalyst solution on { TAIL ~ the substrate }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL