Charge Density Overcomes Steric Hindrance of Ferrocene Surfactant in Switchable Oil-in-Dispersion Emulsions.
Angew Chem Int Ed Engl
; 62(5): e202210050, 2023 Jan 26.
Article
en En
| MEDLINE
| ID: mdl-36328980
ABSTRACT
A ferrocene surfactant can be switched between single and double head form (FcN+ C12 /Fc+ N+ C12 ) triggered by redox reaction. FcN+ C12 can neither stabilize an O/W emulsion alone nor an oil-in-dispersion emulsion in combination with alumina nanoparticles due to the steric hindrance of the ferrocene group. However, such steric hindrance can be overcome by increasing the charge density in Fc+ N+ C12 , so that oil-in-dispersion emulsions can be co-stabilized by Fc+ N+ C12 and alumina nanoparticles at very low concentrations (1×10-7 â
M (≈50â
ppb) and 0.001â
wt %, respectively). Not only can reversible formation/destabilization of oil-in-dispersion emulsions be achieved by redox reaction, but also reversible transformation between oil-in-dispersion emulsions and Pickering emulsions can be obtained through reversing the charge of alumina particles by adjusting the pH. The results provide a new protocol for the design of surfactants for stabilization of smart oil-in-dispersion emulsions.
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Año:
2023
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Article