{HEAD ~ The total thickness} of each interlayer can be in {TAIL ~ the range} of about 5 Å to 20 μm 
{ HEAD ~ The total thickness } of each interlayer can be in { TAIL ~ the range } of about 5 Å to 20 μm
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH