Eur. Phys. J. E 7, 261-266 (2002)
Chain segment ordering in lamellar sublayers of block copolymers: A NMR studyC. Lorthioir1, P. Auroy2, B. Deloche1 and Y. Gallot3
1 Laboratoire de Physique des Solides (CNRS-UMR 8502), Université Paris-Sud, 91405 Orsay, France
2 Institut Curie, Physico-Chimie Curie (CNRS-UMR 168), 11 rue Pierre et Marie Curie, 75005 Paris, France
3 Institut Charles Sadron (CNRS-UPR 22, ULP), 6 rue Boussingault, 67083 Strasbourg, France
(Received 27 September 2001 and Received in final form 18 January 2002)
The chain segment dynamics in the bulk lamellar phase of polystyrene-polydimethylsiloxane (PS-PDMS) block copolymers has been probed by NMR. The experiments were performed on a PS-PDMS diblock and on a PS-PDMS-PS triblock with twice the molecular weight. In the diblock, at room temperature, the PDMS block segments undergo uniaxial reorientations around the normal to the lamellae. In the triblock, the reorientational motions exhibit a lower degree of symmetry: deviations from a uniaxial dynamics are observed. Such a behaviour originates in the anchorage of both PDMS chain ends into the PS glassy layers.
68.08.-p - Liquid-solid interfaces.
82.35.Jk - Copolymers, phase transitions, structure.
76.60.-k - Nuclear magnetic resonance and relaxation.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002