Ultra-Low Molecular Weight Photoswitchable Hydrogelators.
Angew Chem Int Ed Engl
; 60(12): 6764-6770, 2021 03 15.
Article
em En
| MEDLINE
| ID: mdl-33295683
ABSTRACT
Two photoswitchable arylazopyrozoles form hydrogels at a concentration of 1.2 % (w/v). With a molecular weight of 258.28â
g mol-1 , these are the lowest known molecular weight hydrogelators that respond reversibly to light. Photoswitching of the E- to the Z-form by exposure to 365â
nm light results in a macroscopic gelâsol transition; nearly an order of magnitude reduction in the measured elastic and loss moduli. In the case of the meta-arylazopyrozole, cryogenic transmission electron microscopy suggests that the 29±7â
nm wide sheets in the E-gel state narrow to 13±2â
nm upon photoswitching to the predominantly Z-solution state. Photoswitching for meta-arylazopyrozole is reversible through cycles of 365â
nm and 520â
nm excitation with little fatigue. The release of a rhodamineâ
B dye encapsulated in gels formed by the arylazopyrozoles is accelerated more than 20-fold upon photoswitching with 365â
nm light, demonstrating these materials are suitable for light-controlled cargo release.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Austrália