Polymerizable Nonionic Microemulsions:  Phase Behavior of H₂O−n-Alkyl Methacrylate−n-Alkyl Poly(ethylene glycol) Ether (C_iE_j)

Abstract

The phase behavior of ternary water−alkyl methacrylate−alkyl polyglycol ether (C i E j ) systems has been examined. Specifically, using seven different alkyl methacrylates ranging from methyl to hexadecyl methacrylate and C10E6 as surfactant, vertical sections through the phase prism were determined, from which the phase inversion temperature, the upper and lower critical temperature of the three-phase body, and the efficiency of the surfactant and its monomeric solubility in the oil were obtained. Keeping hexyl methacrylate as oil-fixed, 18 different surfactants were applied including short- and long-chain surfactants such as C4E3 and C14E8. The microemulsion systems examined here show the same general patterns as the well-known nonionic microemulsions with alkanes as oil. Notably, the phase inversion temperature is highly dependent on the alkyl chain length of the oil, a fact that is often left out of consideration when choosing a surfactant in emulsion polymerization. For a given oil the phase inversion temperature can be adjusted by appropriate choice of the number of ethylene glycol units of the surfactant. The efficiency of the surfactant systematically depends on the alkyl chain length of both the surfactant and the oil. Interestingly, there is a striking parallel between efficiency of a surfactant and its monomeric solubility in the oil. Finally, in preparation for applying these systems to the synthesis of nanoscaled latexes in microemulsion polymerization the water-rich part of the phase prism was examined. Both the expected shape of the emulsification failure phase boundary and the near-critical phase boundary with its nonmonotonic decay characteristic of branched network structures are delineated. The results of some preliminary polymerizations are briefly discussed.

Determining scaling in known phase diagrams of nonionic microemulsions to aid constructing unknown

“…Having only two points it is not possible to talk about trends in the cyclohexane system but the relation of size of three-phase body and minimum surfactant concentration seems to follow the qualitative trend even if with a different ratio. In E the system with hexadecyl methacrylate is close to the trend but none of the other systems in the different alkyl methacrylate systems came close to the trend when the methacrylates and surfactants were varied [115]. There was no general correlation between size of three-phase body and minimum surfactant concentration for these systems with different "oil".…”

“…[114] and E taken from Ref. [115]. Note that some of the systems (data points) appear in more than one dataset hence data points are on top of each other in a while in b the different T min has separated the data for the different sets.…”

The EACN scale for oil classification revisited thanks to fish diagrams

“…The optimal formulation does not correspond exactly to the same HLD for equal masses of water and oil (black line) and equal volumes of water and oil (grey line). [59][60][61][62][63][64][65][66][67][68][69][70][71][72] with n-alkanes and several selected oils. Experimental T * s for C 10 E 4 and these oils are also included, as well as the melting points of n-alkanes.…”

Self-Propelled Motion of Micrometer-Sized Oil Droplets in Aqueous Solution of Surfactant

“…Various organic reactions, such as polymerizations [14,15], enzymatic reactions [16], and synthetic organic reactions [17][18][19], occur in emulsion systems because of an increase in reagent compatibility, the enhancement of reaction rates, and the induction of regioselectivity. In this section, we introduce the oil droplet system that induces unique dynamics, such as directional motion, division, and deformation, triggered by the molecular conversion of oil and surfactant components.…”