Entropic force on a Polymer
Several micro-manipulation techniques, such as Atomic Foce Microscopy, measure forces required to unravel specific (mostly bio-) polymers.
What is the entropic force on a uniform (phantom or self-avoiding) polymer?
Dimensional analysis suggests:
Work done in moving the tip (with polymer attached) away from the surface is
This work can be related to the difference in free energies, as
Comparing the two expressions yields
"Entropic force of polymers on a cone tip," M. F. Maghrebi, Y. Kantor, M. Kardar, EPL 96, 66002 (2011)