Abstract
We have studied Langmuir monolayers of CH3(CH2) 20OH (heneicosanol) using x-ray diffraction. Over the temperature range 7-55°C, the monolayer isotherms show only one discontinuity, which may be either a "flat section" or a "kink;" we find that these are transitions between tilted and untilted phases. There are several untilted phases, with hexagonal and distorted-hexagonal structures, as in monolayers of the corresponding (heneicosanoic) acid. However, in contrast to the acid, when the pressure is lowered the molecules tilt only towards a next-nearest neighbor. The dependence of the lattice spacings on pressure and temperature indicate that the monolayer does not form a "tilted hexagonal" phase, even at temperatures where the untilted phase is hexagonal (rotator-II).
Original language | English (US) |
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Pages (from-to) | 4485-4488 |
Number of pages | 4 |
Journal | The Journal of Chemical Physics |
Volume | 97 |
Issue number | 6 |
DOIs | |
State | Published - 1992 |
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry