Effect of temperature and solvent on the structure and transport of a tethered membrane: Monte Carlo simulation

Abstract

An extended bond-fluctuation model, introduced previously to study the conformation and dynamics of a self-avoiding sheet (SAS), is further used to understand the temperature dependence on the conformation and dynamics of a tethered membrane (i.e., nodes tethered by fluctuating bonds with excluded volume constraints) in an effective solvent media on a cubic lattice by Monte Carlo simulations. The node-node (nn) and nodesolvent (ns) interactions and temperature orchestrate the stochastic motion of each membrane node, and therefore describe the morphology of the membrane. With increasing temperature, the radius of gyration (R g) of the membrane decreases with repulsive node-node interactions in an attractive solvent medium (ns < 0). The inverse effect is seen in a repulsive medium. Changes in the membrane's R g show that the membrane contracts (stretches) with the range of attractive (repulsive) node-node interaction with more pronounced effects on lowering the temperature. The variations of R g with T, which are affected by wrinkles and crumpling, are complex (with the possibility of stretched exponential functions) depending on the type of membrane, quality of the solvent, and the temperature. Likewise, the segmental dynamics exhibits a range of power-laws, different from that of a SAS, while the global membrane reaches its asymptotic diffusive behavior. © 2005 Wiley Periodicals, Inc.