Molecular dynamics simulations of polyampholytes inside a slit

Abstract

Alternating and diblock polyampholytes confined in a slit with and without an electric field have been simulated by the molecular dynamics method with a Langevin thermostat. It is shown that the slit has a strong effect on the properties of the polyampholyte. The effect is stronger when the electric field is weak, or the temperature is not too high. When a polyampholyte chain moves close to the slit wall, its radius of gyration perpendicular to the wall becomes smaller but that parallel to the wall becomes larger. Owing to the confinement of the slit, the polyampholyte chain closer to the slit wall tends to lie on the wall and becomes more flat. The width of the slit has only a little influence on the properties of solutions near the slit wall, values of several physical statistics are very close with different widths. However, when the electric field strength is strong enough in a narrow slit, the obtained properties obviously differ.

Keywords:

• Polyampholytes
• Molecular dynamics simulation
• Multichain effects
• Diblock polyampholyte

Acknowledgements

This work is supported by the National Natural Science Foundation of China (Projects No.20236010, 20476025, 20490200), E-Institute of Shanghai High Institution Grid (No.200303) and the Shanghai Municipal Education Commission of China.