Ultrafast desorption of colloidal particles from fluid interfaces

Significance Solid particles can replace surfactants to stabilize emulsions and foams. The attachment of particles onto drops and bubbles is typically considered to be irreversible because of a large energy barrier for particle detachment––millions of times the thermal energy for microparticles. Here we demonstrate a method to promote the detachment of microparticles from bubbles using ultrasound. We identified conditions for complete particle removal and recovery in under a millisecond. Our method is programmable in time, and does not require any physicochemical modification of the fluids or the interface. This work addresses the emerging need for methods to recover interfacial particles from emulsions and foams in applications ranging from controlled release to interfacial catalysis and gas storage.