Vapor adsorption is an important process influencing the
migration and the fates of many organic pollutants in the
environment. In this study, adsorption of ethylene glycol (EG)
vapor onto single crystal R-Al2O3 (0001) and fused SiO2
(amorphous) surfaces was studied with sum frequency
generation spectroscopy, a well-suited surface specific
technique for probing interfacial phenomena at the molecular
scale. Air-aqueous EG solutions were also investigated
to compare to the adsorption at the air-solid interface in
the presence of water vapor. The gauche conformer of
EG molecules dominates the air-aqueous EG solution
interface, and EG molecules act as hydrogen acceptors
at the air-liquid interface. Water and surface hydrophilic/
hydrophobic properties play important roles for the
adsorption of EG onto silica and alumina surfaces. The
adsorbed EG molecules interact in different ways at the two
different oxide surfaces. EG molecules weakly physisorb
onto the R-Al2O3 (0001) surface by forming relatively weak
hydrogen bonds with surface water molecules. On the
silica surface, the suppression of the silanol OH stretching
peak indicates that EG molecules form hydrogen bonds
with silanol OH groups.
Introduction 表面和频光谱分析系统(SFG) PL2230系列高能量全固态锁模皮秒Nd:YAG激光器
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