Search

Your search keyword '"Faetti M"' showing total 139 results
Start Over Author "Faetti M"
139 results on '"Faetti M"'

4. Scaling of the rotational relaxation of tracers in o-terphenyl: a linear and nonlinear ESR study

Author

Andreozzi, L., Faetti, M., Giordano, M., and Leporini, D.

Subjects
Supercooled liquids -- Research, Amorphous substances -- Research, Relaxation phenomena -- Case studies, Rotational motion -- Case studies, Electron paramagnetic resonance spectroscopy -- Case studies, Diffusion -- Case studies, Chemicals, plastics and rubber industries
Abstract

A study of diffusion in liquids presents new experimental efforts designed to gain additional insights concerning the reorientation supercooled liquids. The study specifically investigated the rotational dynamics of stiff, molecular tracers with different symmetries in supercooled and glassy O-terphenyl both on the short-time and long-time scale. Among other results, it will be shown that the temperature dependence of the correlation times exhibits three clearly defined regimes on both the short- and long-time scales irrespective of the tracer.

Published
1999

12. Fragility and glass transition temperature in the rheological response of azobenzene copolymers

Author

Andreozzi, L, Faetti, M, Giordano, M, and Zulli, F

Subjects
MOLECULAR-WEIGHT, VISCOELASTIC PROPERTIES, REGULARIZATION METHOD, RELAXATION, POLYMERS
Abstract

Two copolymers containing nonmesogenic methyl methacrylate (MMA) and nematogenic azobenzene methacrylate (MA4) side groups (30/70 and 40/60 copolymers) azobenzene were studied in the linear viscoelastic regime. The time-temperature superposition principle was found to hold over the whole investigated temperature range, even across the nematic-isotropic transition in the 30/70 copolymer. Rheological steady state and oscillatory measurements were used to obtain the temperature dependence of the zero shear viscosity. The strength and dynamic fragility of these two copolymers were compared with those of the corresponding PMA4 and PMMA homopolymers, which pointed out the role of the structure of the main chain in dictating the relaxational dynamics.

Published
2006

13. Heterogeneities in the dynamics of a molecular tracer in mesogenic and nonmesogenic azobenzene copolymers

Author

Andreozzi, L, Autiero, C, Faetti, M, Zulli, F, and Giordano, M

Subjects
POLYMETHACRYLATE THIN-FILMS, OPTICAL MICROSCOPY, POLYMERS, CROSSOVER REGION, SPIN-PROBE
Abstract

We studied by electron spin resonance (ESR) spectroscopy the reorientational dynamics of the cholestane spin probe dissolved in the matrix of the PMA4 40/60 copolymer containing methyl methacrylate (MMA, 40 mol%) and azobenzene methacrylate (MA4, 60 mol%) counits. Heterogeneities in the probe dynamics at the nanometer length scale were evidenced and attributed to the existence of molecular sites with slow and fast spinning correlation times. Different dynamic regimes were also observed with a crossover temperature T-C that was correlated with the glass transition temperature T-g of the copolymer, T-C = 1.17 T-g. Even though the nematic-to-isotropic transition temperature could not be detected, the probe dynamics experienced the onset of nematic order at the molecular level. The results are compared with those of the closely related nematic PMA4 30/70 copolymer.

Published
2006

36. P5-BW5 azione 1-4

Author

Giordano, Marco, Andreozzi, Laura, Faetti, M., Palazzuoli, D., Galli, Giancarlo, Chiellini, Emo, Laus, M., Allegrini, Maria, Patane', S., Labardi, M., Pardi, L., Fontana, M., and Cristofolini, G.

Published
2002

Catalog

Books, media, physical & digital resources
See catalog results