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Characterising the disordered state of block copolymers: Bifurcations of localised states and self-replication dynamics

Published online by Cambridge University Press:  21 December 2011

KARL B. GLASNER*
Affiliation:
Department of Mathematics and Program in Applied Mathematics, University of Arizona, Tucson, AZ 85721, USA4 email: [email protected]

Abstract

Above the spinodal temperature for micro-phase separation in block co-polymers, asymmetric mixtures can exhibit random heterogeneous structure. This behaviour is similar to the sub-critical regime of many pattern-forming models. In particular, there is a rich set of localised patterns and associated dynamics. This paper clarifies the nature of the bifurcation diagram of localised solutions in a density functional model of A−B diblock mixtures. The existence of saddle-node bifurcations is described, which explains both the threshold for heterogeneous disordered behaviour as well the onset of pattern propagation. A procedure to generate more complex equilibria by attaching individual structures leads to an interwoven set of solution curves. This results in a global description of the bifurcation diagram from which dynamics, in particular self-replication behaviour, can be explained.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

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References

[1]Allgower, E. L. & Georg, K. (2003) Introduction to Numerical Continuation Methods, SIAM Classics in Applied Mathematics, Society for Industrial and Applied Mathematics, Philadelphia.CrossRefGoogle Scholar
[2]Bates, F. S., Rosedale, J. H. & Fredrickson, G. H. (May 1990) Fluctuation effects in a symmetric diblock copolymer near the order–disorder transition. J. Chem. Phys. 92, 62556270.CrossRefGoogle Scholar
[3]Bates, F. S. & Fredrickson, G. H. (1999) Block copolymers – designer soft materials. Phys. Today 52, 3238.CrossRefGoogle Scholar
[4]Beck, M., Knobloch, J., Lloyd, D. J. B., Sandstede, B. & Wagenknecht, T. (2009) Snakes, ladders, and isolas of localized patterns. SIAM J. Math. Anal. 41 (3), 936972.CrossRefGoogle Scholar
[5]Bohbot-Raviv, Y. & Wang, Z.-G. (October 2000) Discovering new ordered phases of block copolymers. Phys. Rev. Lett. 85 (16), 34283431.CrossRefGoogle ScholarPubMed
[6]Budd, C. J., Hunt, G. W. & Kuske, R. (December 2001) Asymptotics of cellular buckling close to the Maxwell load. R. Soc. Lond. Proc. Seri. A 457, 29352964.CrossRefGoogle Scholar
[7]Chapman, S. J. & Kozyreff, G. (February 2009) Exponential asymptotics of localised patterns and snaking bifurcation diagrams. Phys. D Nonlinear Phenom. 238, 319354.CrossRefGoogle Scholar
[8]Choksi, R. & Ren, X. (2003) On the derivation of a density functional theory for microphase separation of diblock copolymers. J. Statist. Phys. 113 (1–2), 151176.CrossRefGoogle Scholar
[9]Cross, M. C. & Hohenberg, P. C. (July 1993) Pattern formation outside of equilibrium. Rev. Mod. Phys. 65 (3), 851.CrossRefGoogle Scholar
[10]Dawes, J. H. P. (July 2010) The emergence of a coherent structure for coherent structures: Localized states in nonlinear systems. R. Soc. Lond. Phil. Trans. Seri. A 368, 35193534.Google ScholarPubMed
[11]Dee, G. & Langer, J. S. (1983) Propagating pattern selection. Phys. Rev. Lett. 50, 383386.CrossRefGoogle Scholar
[12]Doelman, A., Kaper, T. J., & Eckhaus, W. (2000) Slowly modulated two-pulse solutions in the Gray–Scott model i: Asymptotic construction and stability. SIAM J. Appl. Math. 61 (3), 10801102.CrossRefGoogle Scholar
[13]Dormidontova, E. E. & Lodge, T. P. (2001) The order–disorder transition and the disordered micelle regime in sphere-forming block copolymer melts. Macromolecules 34 (26), 91439155.CrossRefGoogle Scholar
[14]Elphick, C., Meron, E. & Spiegel, E. A. (1990) Patterns of propagating pulses. SIAM J. Appl. Math. 50 (2), 490503.CrossRefGoogle Scholar
[15]Evans, L. C. (1998) Partial Differential Equations, American Mathematical Society, Providence, RI.Google Scholar
[16]Fredrickson, G. H. (2006) The Equilibrium Theory of Inhomogeneous Polymers, Oxford Science Publications, Clarendon Press, Oxford.Google Scholar
[17]Glasner, K. B. (2010) Spatially localized structures in diblock copolymer mixtures. SIAM J. Appl. Math. 70 (6), 20452074.CrossRefGoogle Scholar
[18]Hamley, I. W. (1998) The Physics of Block Copolymers, Oxford Science Publications, Clarendon Press, Oxford.CrossRefGoogle Scholar
[19]Hashimoto, T., Sakamoto, N. & Koga, T. (1996) Nucleation and growth of anisotropic grain in block copolymers near order–disorder transition. Phys. Rev. E 54 (5), 58325835.CrossRefGoogle ScholarPubMed
[20]Helfand, E. (1975) Theory of inhomogeneous polymers: Fundamentals of the Gaussian random-walk model. J. Chem. Phys. 62 (3), 9991005.CrossRefGoogle Scholar
[21]Hong, K. M. & Noolandi, J. (1981) Theory of inhomogeneous multicomponent polymer systems. Macromolecules 14, 727736.CrossRefGoogle Scholar
[22]Ichiro, E. S., Nishiura, Y. & Ueda, K. I. (2001) 2n-splitting or edge-splitting? A manner of splitting in dissipative systems. Japan J. Ind. Appl. Math. 18, 181205. 10.1007/BF03168570.Google Scholar
[23]Kolokolnikov, T., Ward, M. J. & Wei, J. (2007) Self-replication of mesa patterns in reaction–diffusion systems. Phys. D: Nonlinear Phenom. 236 (2), 104122.CrossRefGoogle Scholar
[24]Leibler, L. (1980) Theory of microphase separation in block copolymers. Macromolecules 13, 16021617.CrossRefGoogle Scholar
[25]Maddocks, J. H. (December 1987) Stability and folds. Arch. Ration. Mech. Anal. 99, 301328.CrossRefGoogle Scholar
[26]Matsen, M. W. & Bates, F. S. (1996) Unifying weak- and strong-segregation block copolymer theories. Macromolecules 29, 10911098.CrossRefGoogle Scholar
[27]Matsen, M. W. & Schick, M. (April 1994) Stable and unstable phases of a diblock copolymer melt. Phys. Rev. Lett. 72 (16), 26602663.CrossRefGoogle ScholarPubMed
[28]Monasson, R. (October 1995) Structural glass transition and the entropy of the metastable states. Phys. Rev. Lett. 75, 28472850.CrossRefGoogle ScholarPubMed
[29]Nishiura, Y. & Ohnishi, I. (1995) Some mathematical aspects of the micro-phase separation of diblock copolymers. Phys. D 84, 3139.CrossRefGoogle Scholar
[30]Nishiura, Y. & Ueyama, D. (June 1999) A skeleton structure of self-replicating dynamics. Phys. D: Nonlinear Phenom. 130, 73104.CrossRefGoogle Scholar
[31]Ohta, T. & Kawasaki, K. (1986) Equilibrium morphology of block coploymer melts. Macromolecules 19, 26212632.CrossRefGoogle Scholar
[32]Ohta, T. & Kawasaki, K. (1990) Comment on the free energy functional of block copolymer melts in the strong segregation limit. Macromolecules 23, 24132414.CrossRefGoogle Scholar
[33]Painter, K. J., Maini, P. K. & Othmer, H. G. (May 1999) Stripe formation in juvenile Pomacanthus explained by a generalized Turing mechanism with chemotaxis. Proc. Natl. Acad. Sci. 96, 55495554.CrossRefGoogle ScholarPubMed
[34]Park, M. J., Char, K., Lodge, T. P. & Kim, J. K. (2006) Transient solidlike behavior near the cylinder/disorder transition in block copolymer solutions. J. Chem Phys. 110, 1529515301.CrossRefGoogle ScholarPubMed
[35]Pearson, J. E. (July 1993) Complex patterns in a simple system. Science 261, 189192.CrossRefGoogle Scholar
[36]Pomeau, Y. (December 1986) Front motion, metastability and subcritical bifurcations in hydrodynamics. Phys. D: Nonlinear Phenom. 23, 311.CrossRefGoogle Scholar
[37]Reynolds, W. N., Pearson, J. E. & Ponce-Dawson, S. (April 1994) Dynamics of self-replicating patterns in reaction diffusion systems. Phys. Rev. Lett. 72, 27972800.CrossRefGoogle ScholarPubMed
[38]Sakamoto, N., Hashimoto, T., Han, C. D., Kim, D. & Vaidya, N. Y. (1997) Order–order and order–disorder transitions in a polystyrene–block–polyisoprene–block–polystyrene copolymer. Macromolecules 30 (6), 16211632.CrossRefGoogle Scholar
[39]Schwab, M. & Stühn, B. (February 1996) Thermotropic transition from a state of liquid order to a macrolattice in asymmetric diblock copolymers. Phys. Rev. Lett. 76, 924927.CrossRefGoogle ScholarPubMed
[40]Semenov, A. N. (1989) Microphase separation in diblock copolymer melts: Ordering of micelles. Macromolecules 22, 28492851.CrossRefGoogle Scholar
[41]Uneyama, T. & Doi, M. (2005) Calculation of the micellar structure of polymer surfactant on the basis of the density functional theory. Macromolecules 38 (13), 58175825.CrossRefGoogle Scholar
[42]Van Saarloos, W. (1988) Front propagation into unstable states: Marginal stability as a dynamical mechanism for velocity selection. Phys. Rev. A 37, 211229.CrossRefGoogle Scholar
[43]Wang, J., Wang, Z.-G. & Yang, Y. (2005) Nature of disordered micelles in sphere-forming block copolymer melts. Macromolecules 38 (5), 19791988.CrossRefGoogle Scholar
[44]Wang, X., Dormidontova, E. E. & Lodge, T. P. (2002) The order–disorder transition and the disordered micelle regime for poly(ethylenepropylene-b-dimethylsiloxane) spheres. Macromolecules 35 (26), 96879697.CrossRefGoogle Scholar
[45]Ward, M. J. (2001) Metastable dynamics and exponential asymptotics in multi-dimensional domains. Multiple-Time-Scale Dynamical Systems, IMA Volumes in Mathematics and its Applications, Springer, New York, pp. 233259.CrossRefGoogle Scholar
[46]Ward, M. J. & Reyna, L. G. (1995) Internal layers, small eigenvalues, and the sensitivity of metastable motion. SIAM J. Appl. Math. 55 (2), 425445.CrossRefGoogle Scholar
[47]Zhang, C.-Z. & Wang, Z.-G (March 2006) Random isotropic structures and possible glass transitions in diblock copolymer melts. Phys. Rev. E 73 (3), 031804.CrossRefGoogle ScholarPubMed