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The Effect of Surface Tension Anisotropy on the Rayleigh Instability in Materials Systems

K.F. Gurski and G.B. McFadden. The Effect of Surface Tension Anisotropy on the Rayleigh Instability in Materials Systems. Introduction to the Rayleigh instability Anisotropic surface energy 2-D equilibrium shapes Rayleigh instability for anisotropic surface energy

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The Effect of Surface Tension Anisotropy on the Rayleigh Instability in Materials Systems

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  1. K.F. Gurski and G.B. McFadden The Effect of Surface Tension Anisotropy on the Rayleigh Instability in Materials Systems • Introduction to the Rayleigh instability • Anisotropic surface energy • 2-D equilibrium shapes • Rayleigh instability for anisotropic surface energy • Conclusions and future work Mathematical and Computational Sciences Division National Institute of Standards and Technology Thanks to S.H. Davis NASA Microgravity, NSF NIRT (NWU)

  2. Rayleigh Instability

  3. Inkjet Printing From Pimbley et al. [1977]. Breakup of a liquid jet into drops.

  4. Cellular Growth during Directional Solidification From Kurowski et al. [1989]. Breakup of liquid grooves into drops during solidification of CBr4.

  5. Instability of Rod Morphology During Monotectic Growth From Majumdar et al. [1996]. Breakup of aligned rods into drops during cooperative monotectic growth of Zinc-Bismuth..

  6. Nanobridge From Kondo et al. [1997]. Free-standing bridge formed by using electron beam irradiation in an ultrahigh vacuum electron microscope.

  7. Quantum Wires From Chen et al. [2000]. STM topographs showing ErSi2 (011) nanowires grown on a flat Si(001) substrate. The Si terraces increase in height from deep blue to green.

  8. Possible Reasons for Enhanced Stability • Quantum effects (Kassubek et al. [2001]). • Elastic effects with substrate (Chen et al. [2000]) • Stabilization by contact angle (McCullum et al. [1996]) • Radial thermal gradients (McFadden et al. [1993]) • Surface energy anisotropy (this work)

  9. Anisotropic Gibbs-Thomson Equation

  10. Cahn-Hoffman Xi-Vector (2-D)

  11. Cahn-Hoffman Xi-Vector (3-D)

  12. 2-D Rod from 3-D Equilibrium Shape

  13. Shape Perturbation

  14. Surface Energy

  15. EigenvalueProblem

  16. EigenvalueProblem

  17. Isotropic Surface Energy

  18. Ellipsoidal Surface Energy

  19. Cubic Material 3-D Equilibrium Shapes for -1/18 < 4 <1/12 High-Symmetry Orientations: [001], [011], [111]

  20. Cubic Material

  21. Asymptotics for |4|<< 1

  22. Numerics • SLEIGN2: Associated Sturm–Liouville Solver • Spectral Decomposition with RS (a real symmetric eigenvalue routine)

  23. [001] Orientation 4 = 1/12 0 -1/18 < 4 < 1/12 1 2

  24. [011] Orientation -1/18 < 4 < 1/12

  25. 011 Orientation 0 1 2

  26. 111 Orientation

  27. Generalized Gauss Curvature

  28. Conclusions • Anisotropic surface energy plays a significant role in the stability of a rod. • Both the magnitude and sign of the anisotropy determine whether the contribution promotes or suppresses the Rayleigh instability. • Different cubic orientations react quite differently to the surface tension anisotropy. Future Work • Missing orientations • Contact angles • Elastic effects

  29. P.B. Bailey, W.N. Everitt, and A. Zettl, Algorithm 810: The SLEIGN2 Sturm-Liouville code, ACM T Math Software 27: (2) Jun 2001 143--192. Y. Chen, D.A.A. Ohlberg, G. Medeiros-Ribeiro, Y.A. Chang, and R.S. Williams, Self-assembled growth of epitaxial erbium disilicide nanowires of silicon(001), App. Phys. Lett., Vol. 76, No. 26 (2000), 4004--4006. M.G. Forest and Q. Wang, Anisotropic microstructure-induced reduction of the Rayleigh instability for liquid crystalline polymers, Phys. Lett. A, 245 (1998) 518--526. J.W. Cahn, Stability of rods with anisotropic surface free energy, Scripta Metall. 13 (1979) 1069-1071. F. Kassubek, C.A. Stafford, H. Grabert, and R.E. Goldstein, Quantum suppression of the Rayleigh instability in nanowires, Nonlinearity 14 (2001) 167--177. P. Kurowski, S. de Cheveigne, G. Faivre, and C. Guthmann, Cusp instability in cellular growth, J. Phys. (Paris) 50 (1989) 3007-3019. Y. Kondo and K. Takayanagi, Gold nanobridge stabilized by surface structure, Phys. Rev. Lett. 79 (1997) 3455-3458. B. Majumdar and K. Chattopadhyay, The Rayleigh Instability and the Origin of Rows of Droplets in the Monotectic Microstructure of Zinc-Bismuth Alloys, Met. Mat. Trans. A, Vol 27A, July (1996) 2053--2057. M.S. McCallum, P.W. Voorhees, M.J. Miksis, S.H. Davis, and H. Wong, Capillary instabilities in solid thin films: Lines, J. Appl. Phys. 79 (1996) 7604-7611. G.B. McFadden, S.R. Coriell, and R.F. Sekerka, Effect of surface tension anisotropy on cellular morphologies, J. Crystal Growth 91 (1988) 180--198. G.B. McFadden, S.R. Coriell, and B.T. Murray, The Rayleigh instability for a cylindrical crystal-melt interface, in Variational and Free Boundary Problems, (ed. A. Friedman and J. Spruck), Vol. 53 (1993) pp. 159-169. References

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