Europhys. Lett.
Volume 47, Number 6, September 1999
Page(s) 675 - 680
Section Atomic and molecular physics
Published online 01 September 2002
DOI: 10.1209/epl/i1999-00442-2

Europhys. Lett, 47 (6), pp. 675-680 (1999)

Escape transition of a compressed polymer mushroom under good solvent conditions

A. Milchev 1,2, V. Yamakov 2,3 and K. Binder 1

1 Institut für Physik, Johannes-Gutenberg-Universität
Staudinger Weg 7, D-55099 Mainz, Germany
2 Institute for Physical Chemistry, Bulgarian Academy of Sciences - 1113, Sofia, Bulgaria
3 Max-Planck-Institut für Polymerforshung
Ackermannweg 10, D-55128, Mainz, Germany

(received 5 February 1999; accepted in final form 12 July 1999)

PACS. 36.20${\rm -r}$ - Macromolecules and polymer molecules.
PACS. 36.20Ey - Conformation (statistics and dynamics).
PACS. 82.45${\rm +z}$ - Electrochemistry and electrophoresis.


The escape transition of a flexible polymer chain of chain length N, endgrafted at a hard wall and compressed by a piston of radius R, is studied by Monte Carlo simulation and by phenomenological arguments. In contrast to previous theories which have considered the transition as a function of a (fixed) height H of the piston above the wall, we consider the transition as a function of the conjugate variable, the force f acting on the piston. We find that the transition (which is sharp only for $ 
N\rightarrow \infty $) is characterized by a flat region of f in the f vs. H isotherm, i.e. a jump in the height occurs at the transition from $H_{{\rm esc},t}$to $H_{{\rm imp},t}$, with $(H_{{\rm imp},t}-H_{{\rm esc},t})/H_{{\rm esc},t}\approx 0.26$.


Copyright EDP Sciences