Autori: M.-C. Popescu, D. Filip, C. Vasile, C. Cruz, J. M. Rueff, M. Marcos, J.L. Serrano, Gh. Singurel

Editorial: J. Phys. Chem. B, 110 , p.14198-1421, 2006.

Rezumat:

FT-IR and 2D correlation spectroscopy were employed to study the microstructural changes ocurring during
phase transitions of a liquid crystal poly(amidoamine) codendrimer (PAMAM (L1)16(L2)16) generation 3,
functionalized on the terminal groups by one-chain promesogenic calamitic units (4-(4′-decyloxybenzoyloxy)-
salicylaldehyde (L1)) and two-chain promesogenic calamitic units (4-(3′,4′-didecyloxybenzoyloxy)salicylaldehyde
(L2)). Spectral modifications associated with molecular conformation rearangements allowing for
molecular shape change on going from a liquid-crystalline organization to another were found. The transition
temperatures were calculated, and they are in good agreement with the DSC data. Spectral analysis gives
evidence of the LC phase transitions and to an additional transition associated with the existence of conformers.
Various types of hydrogen bonding have been established.

Cuvinte cheie: PAMAM dendrimer, IR spectroscopy, 2D correlation spectroscopy