Abstract
Motivated by the finding that colloidal dispersions of polymer micronetwork spheres with a cross-link density of 1:50 (inverse number of monomer units between crosslinks) show significant deviations from the dynamics of hard spheres in the colloid glass as seen by dynamic light scattering (DLS) (E. Bartsch, V. Frenz, H. Sillescu J. Non — Cryst. Solids 172–174 (1994), 88–97), we have undertaken a systematic study of the effect of the crosslink density on the dynamics at high concentrations. Long-time self-diffusion coefficients D LS and collective diffusion coefficients D c were measured for colloids with crosslink densities of 1:10, 1:20 and 1:50 by forced Rayleigh scattering (FRS) and the newly developed thermal diffusion FRS (TDFRS) technique, respectively. Whereas no dependence of D LS on the crosslink density is found at low concentrations and the data coincide with theoretical results for hard spheres, strong effects of the internal architecture on self-diffusion are observed in the highly concentrated regime. Here, hard sphere behaviour is recovered only in case of the 1:10 particles, a glass transition being indicated at φ g ∼ 0.59. Lowering the crosslink density leads to significantly higher (∼ three decades) values of D Ls at φ > φ g. This may be due to an increased deformability of the spheres which could partially account for our DLS results. In contrast, D c is more sensitive to variations of the degree of cross-linking. Here, a much faster increase of D c with volume fraction as compared to hard spheres is observed already at low φ for 1:20 and 1:50 crosslinked particles, the effect being strongest for the lowest crosslink density. The results are tentatively interpreted in terms of a soft repulsive interaction potential, whose range increases on lowering the crosslink density.
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References
Bartsch E, Frenz V, Sillescu H (1994) J Non Cryst Solids 172–174:88–97
van Megen W, Underwood SM (1993) Phys Rev E 49:4206
Stölken S, Bartsch E, Sillescu H, Lindner P (1995) Prog Colloid Polym Sci 98:155–159
Kasper A, Kirsch S, Renth F, Bartsch E, Sillescu H (1996) these proceedings
Köhler W (1993) J Chem Phys 98:660–668
Antonietti M, Bremser W, Müschenborn D, Rosenauer C, Schupp B, Schmidt M (1991) Macromolecules 24:6636–6643
Sillescu H, Ehlich D (1990) In: Fouassier JP, Rabek JB (eds) in Lasers in Polymer Science and Technology: Applications Vol III 211–226; Coutandin J, Ehlich D, Sillescu H, Wang CH (1985) Macromolecules 18:587–589
Koppel DE (1972) J Chem Phys 57:4814–4820
Köhler W, Rossmanith P (1995) J Phys Chem 99:5838
data for the 1:50 crosslinked micronetwork spheres were taken from Bartsch E, Frenz V, Möller S, Sillescu H (1993) Physica A 201:363–371
Medina-Noyola A (1988) Phys Rev Lett 60:2705–2708
Hansen JP, McDonald IR (1986) Theory of Simple Liquids, Academic Press (London)
Fuchs M (1995) In: Yip S (ed) Relaxation Kinetics in Supercooled Liquids — Mode Coupling Theory and its Experimentals Tests, Transp Theory Stat Phys 24:855–880
Since the sample preparation of the measurements reported in ref. [10] was somewhat different from the procedure used here, we cannot fully exclude the possibility that the surprising difference of the 1:20 and 1:50 results is due to experimental artefacts. Further experiments will be necessary in order to substantiate our results.
Pusey PN (1991) In: Levesque D, Hansen JP, Zinn-Justin (eds) Liquids, Freezing and the Glass Transition, Les Houches Session L1, Elsevier, Amsterdam, pp 763–942
Kops-Werkhoven MM, Fijnaut HM (1981) J Chem Phys 74:1618–1625
Kops-Werkhoven MM, Fijnaut HM (1982) J Chem Phys 77:2242–2253
van Megen W, Ottewill RH, Owens SM, Pusey PN (1985) J Chem Phys 82:508–515
Beenakker CWJ, Mazur P (1984) Physica A 126:349
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© 1996 Dr. Dietrich Steinkopff Verlag GmbH & Co. KG
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Renth, F. et al. (1996). The effect of the internal architecture of polymer micronetwork colloids on the dynamics in highly concentrated dispersions. In: Solans, C., Infante, M.R., García-Celma, M.J. (eds) Trends in Colloid and Interface Science X. Progress in Colloid & Polymer Science, vol 100. Steinkopff. https://doi.org/10.1007/BFb0115766
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DOI: https://doi.org/10.1007/BFb0115766
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