IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PENDANT CHAIN DYNAMICS IN MODEL PDMS NETWORKS PROBED BY SPIN DIFFUSION EXPERIMENTS
Autor/es:
R.H. ACOSTA; M.B. FRANZONI; M.A. VILLAR; E.M. VALLÉS; D. A. VEGA; G.A. MONTI
Lugar:
Angra Dos Reis
Reunión:
Congreso; AUREMN 2011 (13th NMR Users Meeting); 2011
Institución organizadora:
AUREMN
Resumen:
Over the last 5 decades the dynamic response of entangled polymer melts has been an outstanding problem in polymer science. Most of the viscoelastic and diffusive properties of polymer melts and concentrated polymer solutions are profoundly influenced by topological interactions. The most successful model to deal with topological constrains is the tube model. According to this model, the topological confinement exerted on a given molecule by the surrounding media can be modeled as a hypothetical tube that severely suppress the motion perpendicular to the tube?s local axis, but permits the diffusion along the tube. Polydimethylsiloxane (PDMS) networks are ideal systems to probe chain dynamics, however, in the context of spin diffusion experiments no work has been carried out to our knowledge to the moment. The usual approach for determination of domain size probed by interaction between different structures does not apply as the whole network, entangled and dangling chains have the same chemical structure. This means that the whole sample has the same spectroscopic components. In this work we propose to use the differences between transverse relaxation times to generate the both the generation of the magnetization gradient and the determination of the spin diffusion.