Hydrophobically modified silica nanolaces-armored water-in-oil pickering emulsions with enhanced interfacial attachment energy

Anisotropic particles with a high aspect ratio led to favorable interfacial adhesion, thus enabling Pickering emulsion stabilization. Herein, we hypothesized that pearl necklace-shaped colloid particles would play a key role in stabilizing water-in-silicone oil (W/S) emulsions by taking advantage of their enhanced interfacial attachment energy.

We fabricated hydrophobically modified silica nanolaces (SiNLs) by depositing silica onto bacterial cellulose nanofibril templates and subsequently grafting alkyl chains with tuned amounts and chain lengths onto the nanograins comprising the SiNLs.

The SiNLs, of which nanograin has the same dimension and surface chemistry as the silica nanospheres (SiNSs), showed more favorable wettability than SiNSs at the W/S interface, which was supported by the approximately 50 times higher attachment energy theoretically calculated using the hit-and-miss Monte Carlo method. The SiNLs with longer alkyl chains from C6 to C18 more effectively assembled at the W/S interface to produce a fibrillary interfacial membrane with a 10 times higher interfacial modulus, preventing water droplets from coalescing and improving the sedimentation stability and bulk viscoelasticity. These results demonstrate that the SiNLs acted as a promising colloidal surfactant for W/S Pickering emulsion stabilization, thereby allowing the exploration of diverse pharmaceutical and cosmetic formulations.