Multi-Walled Carbon Nanotubes as a Cosurfactant for Highly Concentrated Emulsions

Abstract

GRAPHICAL ABSTRACTThe role of multi-wall carbon nanotubes (MWCNT) as a solid surfactant in highly concentrated water-in-oil emulsions was investigated. MWCNT were dispersed in the oil phase. These suspensions are viscoplastic fluids with the yield stress increasing by more than 1000 times with addition of 2% MWCNT, which demonstrates intensive ''structurizing'' ability. After emulsion preparation, MWCNT were concentrated at the interface, stabilizing emulsions. The dependence of the inversion point on MWCNT concentration was found. Emulsions containing up to 94 wt% of the aqueous phase can be prepared only when MWCNT is combined with conventional surfactant. Rheological properties of such compositions were measured. It was established that emulsions stabilized by a combined surfactant were more stable in comparison to conventional surfactant stabilized emulsion.

Effect of Incorporation of Multiwalled Carbon Nanotubes on the Microstructure and Flow Behavior of Highly Concentrated Emulsions

“…35−38 Multiwalled CNTs (MWCNTs) were also utilized as “cosurfactants” along with conventional surfactants to prepare w/o HCEs. 38 Studies on poly high internal phase emulsion (polyHIPE) composite foams provided some useful insights regarding the formation of percolating networks in HCEs. 39−43 Conductive polyHIPE composites having a low electrical percolation threshold were prepared by the polymerization of highly concentrated w/o emulsions incorporated with CNTs, where CNTs were either added in the aqueous phase or in the organic phase.…”

“…Recently, CNTs and several other nanoparticles were incorporated into HCEs either as Pickering stabilizers or as co-stabilizers, and the role of various factors such as the particle size, hydrophobicity, and surfactant/particle ratio on the emulsion stability was studied. − Multiwalled CNTs (MWCNTs) were also utilized as “cosurfactants” along with conventional surfactants to prepare w/o HCEs . Studies on poly high internal phase emulsion (polyHIPE) composite foams provided some useful insights regarding the formation of percolating networks in HCEs. − Conductive polyHIPE composites having a low electrical percolation threshold were prepared by the polymerization of highly concentrated w/o emulsions incorporated with CNTs, where CNTs were either added in the aqueous phase or in the organic phase.…”

Au/CNTs catalyst for highly selective hydrodeoxygenation of vanillin at the water/oil interface

“…It has been reported that solid particles can be used to stabilize aqueous-oil emulsions, which are called Pickering emulsions. [34][35][36][37][38][39][40] The catalytic properties of Pickering emulsions catch the eyes of researchers in recent years. [41][42][43][44][45][46][47][48][49][50][51][52] Carbon nanotube supported metal nanohybrids have been proved that they could act as both recoverable emulsiers and catalysts in our previous work.…”

Innovative Skin Product O/W Emulsions Containing Lignin, Multiwall Carbon Nanotubes and Graphene Oxide Nanoadditives with Enhanced Sun Protection Factor and UV Stability Properties

“…MWCNTs structure (Figure 1c) makes them suitable for stabilizing emulsion due to being harder to desorb from the oil-water interface [31]. During the last decade, the extraordinary stability properties of MWCNTs have encouraged researchers to utilize them as stability agents for O/W emulsions, exhibiting great results [32][33][34]. Moreover, many articles in the literature confirm that MWCNTs may act as excellent UV filters [35,36].…”