When Liquids are Liquids or Maybe Not

We introduce systems of liquids trapped in non-equilibrium configurations by interfacial assemblies of nanoparticle surfactants (‘NPSs’). These constructs consist of aqueous threads, length ~10-100 cm and diameter ~100 m whose mechanical properties are determined by an interfacial NPS assembly 20 nm thick. The interfacial layer consists of nanoparticles and polymers with complementary functionality, that interact only at the oil-water interface, to generate NPS that are irreversibly bound to the oil-water interface.

The shapes can be extensively deformed and reconfigured while maintaining macroscopic structural integrity, and are stable against coalescence. The films are self-healing, so that any ruptures in the film may rapidly be repaired. Furthermore, the system is compatible with a wealth of different nanoparticles, including metallic nanocrystals, meaning the interface can be readily functionalized.

The liquids retain their fluid characteristics: reagents can be flowed through them continuously, and they can be trivially rendered responsive to external stimuli.

Potential applications as a biphasic reaction medium and as responsive, self-regulating systems whose internal environment can be readily altered will be considered.

Speaker: Tom Russell, Univ. of Massachusets, Amherst