Thus, {HEAD ~ the nanoparticles} and TiO2 interact by a mechanism resulting in {TAIL ~ improved spacing} of the TiO2 particles 
Thus , { HEAD ~ the nanoparticles } and TiO2 interact by a mechanism resulting in { TAIL ~ improved spacing } of the TiO2 particles
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH