Structural Changes in Wormlike Micelles on the Incorporation of Small Photoswitchable Molecules
Por:
Rincon-Londono, Natalia, Tavera-Vazquez, Antonio, Garza, Cristina, Esturau-Escofet, Nuria, Kozina, Anna, Castillo, Rolando
Publicada:
7 nov 2019
Resumen:
Chromophores susceptible to light-induced trans-cis isomerization
embedded in cylindrical micelles can modify micelles and their
light-responsive performance. A small chromophore (4-(phenylazo)benzoate
ion) is embedded in cylindrical micelles made of cetyltrimethylammonium
bromide (CTAB) and sodium salicylate (NaSal) in water. The
microstructure is examined by scanning electron microscopy (SEM) and
nuclear magnetic resonance (NMR). Rheological behavior and the length
scales of the micellar network are determined by rheology and
microrheology. The chromophore substantially modifies the micelles even
without UV irradiation. The larger is the chromophore concentration, the
smaller is the micellar length. Additional length scales of the micellar
network do not substantially vary even when NaCl is added. Chromophore
incorporation also modifies the rheology of the micellar solution,
although gradient shear banding is preserved. Viscosity decreases as the
chromophore concentration increases, and viscoelastic spectra are
modified, but when they are correctly rescaled, they can be
superimposed. The addition of the chromophore makes the fluids more
Maxwellian, particularly when NaCl is also added. When the chromophore
is incorporated into the micelles, there is a response after UV
irradiation, although it does not produce a significant rheological
change.
Filiaciones:
Rincon-Londono, Natalia:
Univ Nacl Autonoma Mexico, Inst Fis, POB 20-364, Mexico City 01000, DF, Mexico
Tavera-Vazquez, Antonio:
Univ Nacl Autonoma Mexico, Inst Fis, POB 20-364, Mexico City 01000, DF, Mexico
Univ Chicago, Inst Mol Engn, Chicago, IL 60637 USA
Garza, Cristina:
Univ Nacl Autonoma Mexico, Inst Fis, POB 20-364, Mexico City 01000, DF, Mexico
Esturau-Escofet, Nuria:
Univ Nacl Autonoma Mexico, Inst Quim, POB 70-213, Mexico City 04510, DF, Mexico
Kozina, Anna:
Univ Nacl Autonoma Mexico, Inst Quim, POB 70-213, Mexico City 04510, DF, Mexico
Castillo, Rolando:
Univ Nacl Autonoma Mexico, Inst Fis, POB 20-364, Mexico City 01000, DF, Mexico
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