Monte Carlo simulation of flexible trimers: From square well chains to amphiphilic primitive models

Abstract

In this work, we present Monte Carlo computer simulation results of a primitive model of self-assembling system based on a flexible 3-mer chain interacting via square-well interactions. The effect of switching off the attractive interaction in an extreme sphere is analyzed, since the anisotropy in the molecular potential promotes self-organization. Before addressing studies on self-organization it is necessary to know the vapor liquid equilibrium of the system to avoid to confuse self-organization with phase separation. The range of the attractive potential of the model, λ, is kept constant and equal to 1.5σ, where σ is the diameter of a monomer sphere, while the attractive interaction in one of the monomers was gradually turned off until a pure hard body interaction was obtained. We present the vapor-liquid coexistence curves for the different models studied, their critical properties, and the comparison with the SAFT-VR theory prediction [A. Gil-Villegas, A. Galindo, P. J. Whitehead, S. J. Mills, G. Jackson, and A. N. Burgess, J. Chem. Phys. 106, 4168 (1997)]. Evidence of self-assembly for this system is discussed.

Microcanonical-ensemble computer simulation of the high-temperature expansion coefficients of the Helmholtz free energy of a square-well fluid

“…Thermodynamic and structural properties of the SW system have been fully determined over the years through computer simulations , thermodynamic perturbation methods and integral equation theories [37]- [51]. The combined use of these results has allowed to obtain accurate equations of state valid for the whole range of the fluid phase diagram, and in this way the SW system has become a key ingredient on robust approaches, such as the SAFT-VR method, to model a great variety of three and two-dimensional chain and branched molecular systems [25-27, 52, 53], including the description of lamellar phases [54].…”

Self-assembly of trimer colloids: effect of shape and interaction range

“…15 These trimers were also studied computationally in order to analyze the self-assembled structures and compare with experiment. 15 Other previous simulation studies include trimers with different number of attractive beads, 16,17 dimers, 14,18–21 and tetramers. 22 Recently, Avvisati and Dijkstra simulated trimers with tunable interaction range and bond length in order to study the competition between self-assembly and macroscopic phase separation.…”

Computational study of trimer self-assembly and fluid phase behavior

“…16 In a different computational study, a flexible 3-mer chain with two attractive beads and one repulsive bead at the end of the chain was found to self-assemble. 17 Tetramers with two attractive beads and two repulsive beads were found to self-assemble into a variety of structures and used to study protein aggregation. 18 In this computational study, the phase behavior of a family of trimer models with one attractive central bead and two repulsive beads is investigated for a range of different trimer shapes.…”