Abstract
Monolayers of PFA, a fluorinated surfactant, on water were studied using synchrotron X-ray grazing incidence diffraction (GID) and reflectivity measurements (XR). The uncompressed monolayer is found to self-assemble into crystalline domains giving a strong GID peak. Upon compression and decompression a surface pressure driven solid-solid phase transition takes place.
A hexagonal lattice with vertical molecules at high pressure undergoes a distortion due to a rigid molecular tilt as the pressure is decreased. Bragg rod scans provide conclusive evidence for a tilt of about 20° at 10 nM/m and show the tilt to be towards nearest neighbours. The uncompressed monolayer has a molecular tilt of about 25°.
A hexagonal lattice with vertical molecules at high pressure undergoes a distortion due to a rigid molecular tilt as the pressure is decreased. Bragg rod scans provide conclusive evidence for a tilt of about 20° at 10 nM/m and show the tilt to be towards nearest neighbours. The uncompressed monolayer has a molecular tilt of about 25°.
Original language | English |
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Journal | Journal de physique. Colloque |
Volume | 50 |
Issue number | C7 |
Pages (from-to) | 29-37 |
ISSN | 0449-1947 |
DOIs | |
Publication status | Published - 1989 |