General approach to surface-accessible plasmonic Pickering emulsions for SERS sensing and interfacial catalysis

Abstract

Pickering emulsions represent an important class of functional materials with potential applications in sustainability and healthcare. Currently, the synthesis of Pickering emulsions relies heavily on the use of strongly adsorbing molecular modifiers to tune the surface chemistry of the nanoparticle constituents. This approach is inconvenient and potentially a dead-end for many applications since the adsorbed modifiers prevent interactions between the functional nanosurface and its surroundings. Here, we demonstrate a general modifier-free approach to construct Pickering emulsions by using a combination of stabilizer particles, which stabilize the emulsion droplet, and a second population of unmodified functional particles that sit alongside the stabilizers at the interface. Freeing Pickering emulsions from chemical modifiers unlocks their potential across a range of applications including plasmonic sensing and interfacial catalysis that have previously been challenging to achieve. More broadly, this strategy provides an approach to the development of surface-accessible nanomaterials with enhanced and/or additional properties from a wide range of nano-building blocks including organic nanocrystals, carbonaceous materials, metals and oxides.

SERS as a Probe of Surface Chemistry Enabled by Surface-Accessible Plasmonic Nanomaterials

“…Commun. 2023 , 14 , 1392 . A general and modifier-free approach for the creation of stable Pickering emulsions from charged colloidal nanoparticles with enhanced functionalities in SERS and interfacial catalysis.…”

“…The promoter-assisted interfacial self-assembly approach can also be readily extended to the construction of plasmonic Pickering emulsions, which have potential as biphasic enhancing substrates for important fundamental SERS studies . Pickering emulsions consist of fine liquid droplets, which are covered by a layer of solid particles and dispersed in another immiscible fluid.…”

“…Commun. 2023 , 14 , 1392 . A general and modifier-free approach for the creation of stable Pickering emulsions from charged colloidal nanoparticles with enhanced functionalities in SERS and interfacial catalysis. Li, C.; Chen, Z.; Huang, Y.; Zhang, Y.; Li, X.; Ye, Z.; Xu, X.; Bell, S. E. J.; Xu, Y. Uncovering Strong π-Metal Interactions on Ag and Au Nanosurfaces Under Ambient Conditions via in situ Surface-Enhanced Raman Spectroscopy.…”

“…Here we describe our recent progress in the development of modifier-free approaches for the synthesis and stabilization, assembly ,,− and device construction − of surface-accessible plasmonic nanomaterials (Figure ). The ability to synthesize highly active engineered plasmonic substrates that retain their surface-accessibility, even in complex environments, paves the way for using SERS to study chemical phenomena at molecule–metal interfaces in a way that is not possible with traditional modifier-capped plasmonic substrates.…”

“…The ability to synthesize highly active engineered plasmonic substrates that retain their surface-accessibility, even in complex environments, paves the way for using SERS to study chemical phenomena at molecule–metal interfaces in a way that is not possible with traditional modifier-capped plasmonic substrates. This has allowed us to develop new insights into fundamental surface chemistry ,− and enabled the design of significantly improved plasmonic sensors for important real-life analytes including pharmaceuticals, explosives, “legal highs”, DNA, etc. ,,− More generally, we have shown that the understanding of exposed surfaces which SERS provides can underpin the development of nanomaterials with enhanced and/or novel functionalities that are significant for applications beyond sensing, for example, in catalysis ,,,, and electronics …”