J. Phys. France 51, 2653-2672 (1990)
DOI: 10.1051/jphys:0199000510230265300

Fluctuations in the flat and collapsed phases of polymerized membranes

Farid F. Abraham¹ et David R. Nelson<sup>2

1</sup>  IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099, U.S.A.
²  Lyman Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138, U.S.A.

Abstract
Fluctuations in polymerized membranes are explored via extensive molecular dynamics simulations of simplified « tethered surface » models. The entropic rigidity associated with repulsive second-nearest-neighbor interactions leads to a flattening of « phantom surfaces ». An attractive interaction in the presence of distant self-avoidance leads to a collapsed membrane with fractal dimension three at sufficiently low temperatures. When the attractive interaction is turned off, the surface returns to the flat phase found in earlier simulations. A study of density profiles and hexatic internal order allows a simple physical interpretation of results for the structure function of oriented membranes.

PACS
8239W - Ion exchange, dialysis, osmosis, electro-osmosis, membrane processes.
0540 - Fluctuation phenomena, random processes, noise, and Brownian motion.
8716D - Membranes, bilayers, and vesicles.

Key words
biomembranes -- fluctuations -- fractals -- membranes -- molecular dynamics method -- random processes