ISSN:
1572-8927
Keywords:
cholesteryl oleyl carbonate
;
n-alkanes
;
heat capacity of transfer
;
volume of transfer
;
segmental motion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Heat capacities ΔC p and volumes ΔV have been obtained at 25°C for the transfer of cholesteryl oleyl carbonate (ChOC) from a reference solvent, the highly-branched alkane 2,2,4,4,6,8,8-heptamethylnonane into various solvents. These include normal, branched, and cyclic alkanes as well as the pure cholesteric ChOC. ΔV and most ΔC p are associated with the change of environmental free volume during the transfer process and are predicted by the Prigogine-Flory theory. However, for n-alkane solvents with more than twelve carbons, ΔC p is large, positive, and unattributable to free volume changes. It is consistent with a restriction of alkane segmental motion by the ChOC. The same mechanism has been proposed to explain an antiplasticization effect of ChOC on transitions in polymers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00645192
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