Using surface selective triplet state solvation techniques, we study the relaxation behavior of nonpolar liquids near their glass transition in confinement to porous glass with 4 nm pore diameter. As specific liquid-surface interactions are not expected for alkanes, we ask whether a substantial frustration of the dynamics is a general phenomenon for such liquids, and how the effects change with surface silanization. We find that interfacial dynamics display relaxation times that are increased by orders of magnitude for several nonpolar molecular liquids. Silanization removes this frustration effect almost entirely. Regarding the comparison of native versus silanized pore surfaces, it is concluded that the strong adhesive forces involved in alkanes wetting silica can explain the sluggish interfacial dynamics. The findings are not consistent with finite size effects.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry