Janus helices: From fully attractive to hard helices

Area of Science:

• Thermodynamics and Statistical Mechanics
• Soft Matter Physics
• Computational Materials Science

Background:

• Hard helices exhibit unique phase behavior, including chiral screw phases, distinct from hard rods.
• Solvent-induced interactions can be modeled as short-range attractive tails on particle sites.
• Understanding these interactions is crucial for predicting phase transitions in complex fluids.

Purpose of the Study:

• To investigate the influence of short-range attractive interactions on the phase diagram of hard helices.
• To determine how varying fractions of attractive sites affect liquid crystal and screw phases.
• To analyze the interplay between entropy and attractive forces in helical particle systems.

Main Methods:

• Extensive Monte Carlo simulations.
• Molecular Dynamics simulations.
• Analysis of phase diagrams and equation of state.

Main Results:

• Attractive interactions marginally affect the existence and location of liquid crystal and screw phases.
• Phase behavior remains predominantly entropically driven at temperatures above Boyle temperatures.
• Pressure decreases with increasing attractive site fraction or decreasing temperature at fixed volume fraction.

Conclusions:

• Chiral screw phases remain stable across studied conditions.
• Smectic phases become more stable at lower temperatures.
• Transition line dependence on attractive site fraction is complex and not simply monotonic.