Coarse grained models for flexible liquid crystals: parameterization of the bond fluctuation model

Area of Science:

• Polymer physics and materials science.
• Computational chemistry and molecular modeling.

Background:

• The bond fluctuation model is a coarse-grained simulation technique for polymer systems.
• Simulating complex flexible molecules like liquid crystalline polymers and dendrimers requires models that capture anisotropic interactions.

Purpose of the Study:

• To extend the bond fluctuation model to incorporate anisotropic interactions for simulating large flexible molecules.
• To investigate the relationship between molecular stiffness and the phase behavior of liquid crystalline polymers.

Main Methods:

• The bond fluctuation model was modified to include anisotropic interactions.
• Trial simulations were performed on a low molar mass liquid crystalline system to obtain interaction parameters.
• The phase diagram was determined as a function of molecular stiffness.

Main Results:

• The extended model successfully simulates flexible chains with anisotropic interactions at a mesogenic unit level.
• A phase diagram was generated for the liquid crystalline system, varying molecular stiffness.
• The nematic to isotropic transition temperature was observed to increase with increasing molecular stiffness.

Conclusions:

• The modified bond fluctuation model is suitable for simulating complex flexible molecules like liquid crystalline polymers and dendrimers.
• Molecular stiffness is a critical factor influencing the phase transitions in these systems.
• The study provides a computational framework for understanding the behavior of advanced polymer materials.