Induced nematic–like phase in dipolar and quadrupolar colloids
O. Alarcón–Waess
Departamento de Física y Matemáticas, UDLA, Puebla, Sta. Catarina Martir, Cholula 72820 Puebla, Mexico.
Recibido el 18 de abril de 2005
Aceptado el 31 de octubre de 2005
Abstract
We compute the one–body probability density function of a dipolar and a quadrupolar colloid driven by an external ordering field. Colloids with low structure in the absence of the external field, and with axially symmetric coupling potential are assumed. To compute the one–body probability density function, it is assumed that the dynamics of the colloid are given by the Smoluchowski equation without hydrodynamic interactions. We use an appropiate homogeneous external field for each moment. The results for the one–body probability density function predict an axial nematic–like phase for the dipole moment, whereas a biaxial nematic–like phase is predicted for the quadrupole moment.
Keywords: Colloid; nematics; multipole; one–body density function.
Resumen
Calculamos la densidad de probabilidad de un cuerpo de un coloide dipolar y uno cuadrupolar controlados por un campo externo ordenador. Consideramos un coloide con poca estructura en ausencia del campo externo y con potencial de interacción axialmente simétrico. Para calcular la funcion de densidad de probabilidad suponemos que la dinámica del coloide esta dada por la ecuación de Smoluchowski sin interacciones hidrodinamicas. Usamos un campo homogeneo externo apropiado para cada momento. Los resultados, para la función de densidad de probabilidad de un cuerpo, predicen una fase axial tipo nematica para el dipolo, mientras que una fase biaxial tipo nemática se obtiene para el momento cuadrupolar.
Descriptores: Coloide; nematico; multipolo; funcion de densidad de un cuerpo.
PACS: 82.70.Dd; 05.40.–a; 64.70.Md
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Acknowledgement
We are grateful to A. Gil–Villegas, from the Universidad de Guanjuato, México, for a fruitful discussion on liquid crystals.
References
1. P.G. de Gennes and J. Prost, The Physics of Liquid Crystals (Clarendon Press, Oxford 1998). [ Links ]
2. D. Frenkel, in Liquids, Freezing and Glass Transition, Les Houches Summer School Lectures, Vol 11, edited by J. P. Hansen, D. Levesque, and J. Zinn–Justin (Elsevier, Amsterdam, 1991). [ Links ]
3. S. Chandrasekhar, Liquid Crystals (Cambridge University Press, Cambridge 1992). [ Links ]
4. H. Stark, Phys. Rep. 351 (2001) 387. [ Links ]
5. D. Wei and G.N. Patey, Phys. Rew. Letts. 68 (1992) 2043. [ Links ]
6. S.H.L. Klapp and G.N. Patey, J. Chem. Phys. 112 (2000) 3832. [ Links ]
7. K. Butter et al., Nature materials 2 (2003) 88. [ Links ]
8. P.G. de Gennes and P.A. Pincus, Phys. Kondens. Mater. 11 (1970) 189. [ Links ]
9. E.F. Gramsbergen, L. Longa and W.H. de Jeu, Phys. Reps. 135 (1986) 195. [ Links ]
10. P. Plafly–Muhoray, J.R. de Bruyn and D.A. Dummur, J. Chem. Phys. 82 (1985) 5294. [ Links ]
11. R. Hashin, G.R. Luckhurst and S. Romano, Mol. Phys. 53 (1985) 1535. [ Links ]
12. N. Ibarra–Avalos, A. Gil–Villegas, A. Martinez–Rocha, in Developments in Mathematical and Experimental Physics, Vol B: Statistical Physics and Beyond (Kluwer Academic Press, New York, 2003). [ Links ]
13. S. Hess and M. Kroger, J. Phys: Condens. Matter 16 (2004) S3835. [ Links ]
14. C. Zannoni, in The Molecular Physics of Liquid Crystals, edited by G.R. Luckhurst and G.W. Gray (Academic, New York, 1979). [ Links ]
15. R.B. Jones, P.N. Pusey, Annu. Rev. Phys. Chem. 42 137 (1991). [ Links ]
16. J.K.G. Dhont, An Introduction to Dynamics of Colloids (Elsevier, Amsterdam, 1996). [ Links ]
17. G. Naegele, Phys. Rep. 272 (1996) 215. [ Links ]
18. C.G. Gray and K.E. Gubbins, Theory of Molecular Fluids (Clarendon Press, Oxford, 1984). [ Links ]
19. S.W. de Leeuw, J.W. Perram, and E.R. Smith, Proc. R. Soc. London Ser. A 388 (1983) 177. [ Links ]
20. P.H. Fries and G.N. Patey, J. Chem, Phys. 82 (1985) 429. [ Links ]
21. D. Wei, G.N. Patey and A. Perera, Phys. Rev. E 47 (1993) 506. [ Links ] ]]>