Quantitative model for prediction of hydrodynamic size of nonionic reverse micelles

Abstract

The sizes of nonionic reverse micelles were investigated as a function of the molecular structure of the surfactant, the type of oil, the total concentration of surfactant [NP], the ratio of surfactant to total surfactant (r), the water to surfactant molar ratio (omega), temperature, salt concentration, and polar phase. The basis of our investigation was a mixture of nonylphenol polyethoxylates--NP4 and NP7, various polar phases, and several oils. Micelle sizes were determined using dynamic light scattering (DLS). A central composite experimental design was used to quantitatively model micelle size as a function of omega, surfactant concentration, and r. The model has demonstrated the capability of predicting the mean diameter of micelles from 4 to 13 with a precision of +/-2 nm as measured by DLS. This quantitative correlation between the size of reverse micelles and the synthetic variables provides the foundation for choosing experimental conditions to control reverse micelle size. In turn, this allows control of the size of nanoparticles synthesized within them.

Experimental and Theoretical Efforts to Identify the Microstructural Transition of Water to Acetonitrile‐Based Reverse Micelle through Binary Compositions of Polar Solvents

“…It is clear from the plot that the temperature‐sensitivity is gradually reduced on going from aqueous RMs to non‐aqueous RMs. This dependence seems obvious if one considers the extent of H‐bonding ability in these systems and is attributed to a disruption of H‐bonding, between the water and the polar head group of DDAB molecule at high temperature . As the system proceeds towards the ACN‐rich RMs, the lack of H‐bonding ability of ACN with surfactant actually provides more temperature insensitivity to the formulated systems.…”

Membrane Synthesized from Microemulsion‐Derived Ilmenite Nano Powders Used for Removal of Red Dye from Textile Industry

“…TEM micrograph of different FeTiO 3 powders synthesized with 0.5:1 and 2.5:1 water–surfactant ratio is shown in the inset of corresponding XRD patterns. According to the literature, micelle size increases with a decrease in surfactant concentration when the other parameters are held constant . When water was added to reverse micelles, a portion of the water got distributed to the interface and hydrates the head groups until they reach a maximum, becoming fully hydrated at a certain Wo.…”

“…According to the litera-ture, micelle size increases with a decrease in surfactant concentration when the other parameters are held constant. 34 When water was added to reverse micelles, a portion of the water got distributed to the interface and hydrates the head groups until they reach a maximum, becoming fully hydrated at a certain Wo. Additional water then goes primarily to the inner core, leading to a continuous increase in the volume of core water with a further increase in Wo.…”

Annealing temperature and initial iron valence ratio effects on the structural characteristics of nanoscale nickel zinc ferrite

“…According to the literature, these ratios should produce reverse micelles with a hydrodynamic diameter of approximately 8.34 nm. 13 The mixed metal chloride salt solution was then quickly added to the deoxygenated surfactant solution in the addition funnel and held under flowing nitrogen. Next, 5.0 ml of concentrated ammonium hydroxide was added to the degassing surfactant solution in the reaction flask.…”