Thermodynamic properties of n-alkanes in porous graphite

Abstract

Differential scanning calorimetry on very thin layers of n-alkanes confined in the pores of delaminated graphite is reported. The thermodynamic behaviour of the strongly adsorbed component at the graphite surface and the apparently ‘bulk-phase’ component (from the point of view of X-ray diffraction) is analysed. The adsorbed phase is of the same crystalline form whatever the parity of the n-alkanes and has the same thermodynamic properties, as revealed by differential scanning calorimetry. A study of the solid–solid and solid–liquid transitions of the ‘bulk phase’ confined in the pores shows that the solid–solid transition is the most affected by the confinement in the pores and its temperature is decreased.