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Light Responsiveness and Assembly of Arylazopyrazole-Based Surfactants in Neat and Mixed CTAB Micelles.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Tyagi, Gunjan 
Greenfield, Jake L 
Sharratt, William N  ORCID logo  https://orcid.org/0000-0003-2148-8423
Khan, Kasim 

Abstract

The self-assembly of an arylazopyrazole-based photosurfactant (PS), based on cetyltrimethylammonium bromide (CTAB), and its mixed micelle formation with CTAB in aqueous solution was investigated by small angle neutron and X-ray scattering (SANS/SAXS) and UV-vis absorption spectroscopy. Upon UV light exposure, PS photoisomerizes from E-PS (trans) to Z-PS (cis), which transforms oblate ellipsoidal micelles into smaller, spherical micelles with larger shell thickness. Doping PS with CTAB resulted in mixed micelle formation at all stoichiometries and conditions investigated; employing selectively deuterated PS, a monotonic variation in scattering length density and dimensions of the micellar core and shell is observed for all contrasts. The concentration- and irradiance-dependence of the E to Z configurational transition was established in both neat and mixed micelles. A liposome dye release assay establishes the enhanced efficacy of photosurfactants at membrane disruption, with E-PS exhibiting a 4-fold and Z-PS a 10-fold increase in fluorescence signal with respect to pure CTAB. Our findings pave the way for external triggering and modulation of the wide range of CTAB-based biomedical and material applications.

Description

Keywords

photosurfactant, CTAB, arylazopyrazole, micelle, SANS, SAXS, liposome

Journal Title

JACS Au

Conference Name

Journal ISSN

2691-3704
2691-3704

Volume Title

2

Publisher

American Chemical Society (ACS)
Sponsorship
EPSRC (EP/T517847/1)
EPSRC (2438208)