Regular Articles

Full Text / References

Molecular Dynamics Simulation of Phase Behavior in a Bolaamphiphilic Solution

Susumu FUJIWARA, Takumi MIYATA, Masato HASHIMOTO, Yuichi TAMURA¹⁾, Hiroaki NAKAMURA²⁾ and Ritoku HORIUCHI²⁾

Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan

1)

Konan University, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan

2)

National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan

(Received 26 November 2014 / Accepted 5 February 2015 / Published 16 April 2015)

Abstract

The phase behavior of bolaamphiphilic solutions is studied by coarse-grained molecular dynamics simulations of semiflexible bolaamphiphilic molecules with explicit solvent molecules. Our simulations show that six kinds of self-assembled structures (spherical micelles, worm-like micelles, bicontinuous structure, hexagonal structure, plate-like micelles, and lamellar structure) are obtained. It is established that, at low concentrations, a plate-like micelle changes to worm-like micelles, and then to spherical micelles as the hydrophilic interaction increases. Conversely, at intermediate concentrations, a lamellar structure changes to a bicontinuous structure; it then changes to worm-like micelles or a hexagonal structure as the hydrophilic interaction increases. It is also observed that the global orientational order parameter for the end bonds of bolaamphiphilic molecules can be used to clearly distinguish between the randomly-oriented structures (the spherical micelles, the worm-like micelles, and the bicontinuous structure), the lamellar structure, the hexagonal structure, and the plate-like micelles.

Copyright (c) 2015 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

molecular dynamics simulation, phase behavior, bolaamphiphilic solution, hydrophilic interaction, orientational order parameter

DOI: 10.1585/pfr.10.3401029

Full Text

PDF format (857Kbytes)

References

• [1] S. Fujiwara, M. Hashimoto and T. Itoh, J. Plasma Phys. 72, 1011 (2006).
• [2] S. Fujiwara, T. Itoh, M. Hashimoto and Y. Tamura, Mol. Simul. 33, 115 (2007).
• [3] S. Fujiwara, T. Itoh, M. Hashimoto and R. Horiuchi, J. Chem. Phys. 130, 144901 (2009).
• [4] S. Fujiwara, T. Itoh, M. Hashimoto, H. Nakamura and Y. Tamura, Plasma Fusion Res. 5, S2114 (2010).
• [5] S. Fujiwara, T. Itoh, M. Hashimoto, Y. Tamura, H. Nakamura and R. Horiuchi, Plasma Fusion Res. 6, 2401040 (2011).
• [6] S. Fujiwara, D. Funaoka, T. Itoh and M. Hashimoto, Comput. Phys. Commun. 182, 192 (2011).
• [7] S. Fujiwara, M. Hashimoto, T. Itoh and R. Horiuchi, Chem. Lett. 41, 1038 (2012).
• [8] S. Fujiwara, M. Hashimoto, Y. Tamura, H. Nakamura and R. Horiuchi, Plasma Fusion Res. 9, 3401067 (2014).
• [9] S. Fujiwara and T. Sato, J. Chem. Phys. 107, 613 (1997).
• [10] S. Fujiwara and T. Sato, J. Chem. Phys. 114, 6455 (2001).
• [11] S. Fujiwara and T. Sato, Phys. Rev. Lett. 80, 991 (1998).
• [12] S. Fujiwara and T. Sato, J. Chem. Phys. 110, 9757 (1999).
• [13] S. Fujiwara and T. Sato, Comput. Phys. Commun. 142, 123 (2001).
• [14] S. Fujiwara, M. Hashimoto, T. Itoh and H. Nakamura, J. Phys. Soc. Jpn. 75, 024605 (2006).
• [15] J.N. Israelachvili, Intermolecular and Surface Forces (Academic Press, London, 1992) 2nd ed.
• [16] Micelles, Membranes, Microemulsions, and Monolayers, edited by W.M. Gelbart, A. Ben-Shaul and D. Roux (Springer-Verlag, New York, 1994) pp.1-104.
• [17] I.W. Hamley, Introduction to Soft Matter (J. Wiley, Chichester, 2007) Rev. ed.
• [18] R. Shirasaki, Y. Yoshikai, H. Qian, S. Fujiwara, Y. Tamura and H. Nakamura, Plasma Fusion Res. 6, 2401116 (2011).
• [19] X. Li, I.V. Pivkin, H. Liang and G.E. Karniadakis, Macromolecules 42, 3195 (2009).
• [20] R. Goetz and R. Lipowsky, J. Chem. Phys. 108, 7397 (1998).
• [21] M.P. Allen and D.J. Tildesley, Computer Simulation of Liquids (Clarendon, Oxford, 1987).

This paper may be cited as follows:

Susumu FUJIWARA, Takumi MIYATA, Masato HASHIMOTO, Yuichi TAMURA, Hiroaki NAKAMURA and Ritoku HORIUCHI, Plasma Fusion Res. 10, 3401029 (2015).