Direct measurement of force configurational entropy in jamming

Configurational Entropy Revisited

1548 Journal of Chemical Education • Vol. 84 No. 9 September 2007 • www.JCE.DivCHED.org Entropy change is categorized in some prominent general chemistry textbooks as being either positional (configurational) or thermal. Positional entropy focuses on the number of positions in space that can be occupied by the molecules of a system. Then, to the extent that more positions exist after a process ...

Configurational entropy of hard spheres

We numerically calculate the configurational entropy Sconf of a binary mixture of hard spheres, by using a perturbed Hamiltonian method trapping the system inside a given state, which requires less assumptions than the previous methods [R.J. Speedy, Mol. Phys. 95, 169 (1998)]. We find that Sconf is a decreasing function of packing fraction φ and extrapolates to zero at the Kauzmann packing frac...

Configurational Entropy in Chiral Solutions - Negative Entropy of Solvent Envelopes

A homogeneous solution of a chiral substance is acquired with an overall asymmetry which is expressed by a specific rotation of a linearly polarized light. Such a solution, despite being at a complete equilibrium, stores configurational entropy in a form of negative entropy which can be nullified by mixing with a solution of the opposite enantiomer. This abundant, yet quite a specific case of i...

Direct measurement of the magnetic entropy change

Direct Force Measurement of Liposomes by Atomic Force Microscopy

Liposomes serve as models for cells and show increasing applications in medical and nonmedical fields. Unilamellar vesicles are prepared from multilamellar vesicle (MLV) dispersions either by sonication or extrusion. The shape stability of liposomes is important in the understanding of membrane fusion, as well as in drug delivery and gene therapy. Therefore it has been the subject of numerous t...