MONTE-CARLO COMPARATIVE-STUDY OF MODEL DETERGENT AND LIPID AGGREGATION ON A LATTICE

We have studied the aggregation of model amphiphilic molecules on a sq uare lattice through Monte Carlo simulations via Metropolis. Amphiphil ic molecules are modeled with a hydrophilic head represented by a smal l set of ''water-loving'' sites whereas the hydrophobic double-tail is represented by a second set of oil-loving sites. We have compared agg regation properties of single-tail (detergents) and double-tail (phosp holipids) amphiphiles with equivalent hydrophobicity ratios. Equilibri um quantities such as average particle energy, specific heat, free amp hiphile density show similar behavior for both model systems. The tran sition region associated with aggregation occurs at high temperatures for phospholipids as compared to detergents.