Synthesis of amphiphilic fluorinated Janus particles with applications in stabilizing surfactant-free foams

Abstract We report the preparation of amphiphilic Janus particles covered with fluorinated chains as well as the self-assembly and foam stabilization property of these particles over a limited range of concentrations. The structure and properties of these particles were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, fluorescence microscopy, pendant drop tensiometer, and foamscan. At a particle concentration of 0.6 wt%, the adsorption of the Janus particles at the interface was saturated and an equilibrium surface tension of approximately 35 mN/m was obtained. No further decreases in surface tension were observed with additional increases in the particle concentration. At a concentration of 0.4 wt%, the Gibbs stability criterion was achieved and the foam volume was almost constant throughout the observation period. Additionally, the liquid fraction of the foam exhibited a static equilibrium at each concentration assessed, demonstrating that drainage was arrested effectively. These results confirm that the use of amphiphilic Janus particles is an efficient approach to stabilizing foams.