TY - JOUR
T1 - Photo-Responsive Control of Adsorption and Structure Formation at the Air–Water Interface with Arylazopyrazoles
AU - Hardt, Michael
AU - Busse, Franziska
AU - Raschke, Simon
AU - Honnigfort, Christian
AU - Carrascosa-Tejedor, Javier
AU - Wenk, Paul
AU - Gutfreund, Philipp
AU - Campbell, Richard A.
AU - Heuer, Andreas
AU - Braunschweig, Björn
PY - 2023/4/25
Y1 - 2023/4/25
N2 - Smart interfaces that are responsive to external triggers such as light are of great interest for the development of responsive or adaptive materials and interfaces. Using alkyl-arylazopyrazole butyl sulfonate surfactants (alkyl-AAP) that can undergo E/Z photoisomerization when irradiated with green (E) and UV (Z) light, we demonstrate through a combination of experiments and computer simulations that there can be surprisingly large changes in surface tension as well as in the molecular structure and order at air-water interfaces. Surface tensiometry, vibrational sum-frequency generation (SFG) spectroscopy and neutron reflectometry (NR) are applied to the study of custom-synthesized AAP surfactants with octyl- and H-terminal groups at air-water interfaces as a function of their bulk concentration and E/Z configuration. Upon photoswitching, a drastic influence of the alkyl chain on both the surface activity and the responsiveness of interfacial surfactants is revealed from changes in the surface tension, γ, where the largest changes in γ are observed for octyl-AAP (∆γ~23 mN/m) in contrast to H-AAP with ∆γ
AB - Smart interfaces that are responsive to external triggers such as light are of great interest for the development of responsive or adaptive materials and interfaces. Using alkyl-arylazopyrazole butyl sulfonate surfactants (alkyl-AAP) that can undergo E/Z photoisomerization when irradiated with green (E) and UV (Z) light, we demonstrate through a combination of experiments and computer simulations that there can be surprisingly large changes in surface tension as well as in the molecular structure and order at air-water interfaces. Surface tensiometry, vibrational sum-frequency generation (SFG) spectroscopy and neutron reflectometry (NR) are applied to the study of custom-synthesized AAP surfactants with octyl- and H-terminal groups at air-water interfaces as a function of their bulk concentration and E/Z configuration. Upon photoswitching, a drastic influence of the alkyl chain on both the surface activity and the responsiveness of interfacial surfactants is revealed from changes in the surface tension, γ, where the largest changes in γ are observed for octyl-AAP (∆γ~23 mN/m) in contrast to H-AAP with ∆γ
KW - Sum-Frequency Generation
KW - Photoresponsive Materials
KW - Neutron Reflectometry
KW - Ultra Coarse-Grained Simulations
KW - Fluid Interfaces
KW - Photoisomerization
UR - https://www.scopus.com/pages/publications/85153802719
U2 - 10.1021/acs.langmuir.3c00294
DO - 10.1021/acs.langmuir.3c00294
M3 - Article
SN - 0743-7463
VL - 39
SP - 5861
EP - 5871
JO - Langmuir
JF - Langmuir
IS - 16
ER -