We introduce systems of liquids, trapped in non-equilibrium configurations by the jamming of interfacial assemblies of nanoparticle surfactants (‘NPSs’). These constructs consist of aqueous tubules, ~10-100 cm in length and ~100 mm in diametter whose mechanical properties are determined by an interfacial NPS assembly 20 nm thick. The interfacial layer consists of functionalized nanoparticles dispersed in an aqueous phase and polymers having a complementary functionality, that interact only at the oil-water interface, to generate NPS that are irreversibly bound to the oil-water interface. The shapes of the liquid phases can be extensively deformed and reconfigured while maintaining macroscopic structural integrity and are stable against coalescence. The films are also self-healing, so that any ruptures in the film are rapidly repaired. These structured liquids can be prepared using a wealth of different nanoparticles, including metallic nanocrystals, meaning the interface can be readily functionalized with the properties characteristic of the NPs. The liquids retain their fluid characteristics: reagents can be flowed through them continuously, and they can be rendered responsive to external stimuli. In the case of paramagnetic nanoparticles, the interfacial jamming of the NPs in a magnetic field can transform an initial ferrofluid droplet into a ferromagnetic liquid droplet, producing a completely new form of magnetic material. If the paramagnetic NPs are overpacked at the interface, storing a potential energy, zn explosive spontaneous emulsification occurs, jettisoning ferromagnetic liquid rolets from the interface at velocities exceeding 1 mm/s. Potential applications of structured liquid include biphasic reaction medium and responsive, self-regulating systems whose internal environment can be readily altered.

When liquids are liquids or maybe not

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.