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Structure and dynamics of polymer chains in hydrophilic nanocomposites |
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| Authors: | S. Fotiadou K. Chrissopoulou B. Frick S. H. Anastasiadis |
| Affiliation: | 1. Institute of Electronic Structure and Laser, Foundation for Research and Technology—Hellas, P. O. Box 1527, 711 10 Heraklion Crete, Greece Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;2. Institute of Electronic Structure and Laser, Foundation for Research and Technology—Hellas, P. O. Box 1527, 711 10 Heraklion Crete, Greece;3. Institut Laue Langevin, 6 rue Jules Horowitz, F38042 Grenoble Cedex, France;4. Institute of Electronic Structure and Laser, Foundation for Research and Technology—Hellas, P. O. Box 1527, 711 10 Heraklion Crete, Greece Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece Department of Chemistry, University of Crete, P. O. Box 2208, 710 03 Heraklion Crete, Greece |
| Abstract: | Poly(hexa(ethylene glycol) methacrylate)/sodium montmorillonite, (PHEGMA/Na+-MMT) nanocomposites with varying composition were synthesized utilizing melt intercalation and solution mixing. Intercalated hybrids were obtained but, for the solution prepared hybrids, the equilibrium structure could only be reached following thermal annealing. At equilibrium, all nanocomposites showed the same interlayer distance independent of the hybrid composition. For low polymer content nanocomposites, where all polymer chains reside within the inorganic galleries, the glass transition temperature of PHEGMA was completely suppressed. Quasielastic neutron scattering was utilized to investigate the effect of severe confinement on the dynamics of the intercalated polymer chains. Both elastic and quasielastic measurements were performed and showed that the confined system exhibits a much weaker temperature and wavevector dependence of the elastic intensity and of the respective relaxation times. The segmental mean square displacement in confinement begins to increase at temperatures well below the bulk polymer glass transition, indicating enhanced mobility compared with the pure polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1658–1667, 2010 |
| Keywords: | clay confinement dynamics glass transition hydrophilic polymers nanocomposites quasielastic neutron scattering |