Molecular Basis for the Morphological Transitions of Surfactant Wormlike Micelles Triggered by Encapsulated Nonpolar Molecules

Abstract

Surfactant wormlike micelles are prone to experience morphological changes, including the transition to spherical micelles, upon the addition of nonpolar additives. These morphological transitions have profound implications in diverse technological areas, such as the oil and personal-care industries. In this work, additive-induced morphological transitions in wormlike micelles were studied using a molecular theory that predicts the equilibrium morphology and internal molecular organization of the micelles as a function of their composition and the molecular properties of their components. The model successfully captures the transition from wormlike to spherical micelles upon the addition of a nonpolar molecule. Moreover, the predicted effects of the concentration, molecular structure, and degree of hydrophobicity of the nonpolar additive on the wormlike-to-sphere transition are shown to be in good agreement with experimental trends in the literature. The theory predicts that the location of the additive in the micelle (core or hydrophobic–hydrophilic interface) depends on the additive hydrophobicity and content, and the morphology of the micelles. Based on the results of our model, simple molecular mechanisms were proposed to explain the morphological transitions of wormlike micelles upon the addition of nonpolar molecules of different polarities.

Lubrication and Dynamically Controlled Drug Release Properties of Tween 85/Tween 80/H2O Lamellar Liquid Crystals

“…Figure a shows the molecular self-assembly models of Tween 85/Tween 80/H 2 O lamellar liquid crystals. The interlayer thickness d of lamellar liquid crystals consists of an aqueous layer d w and an amphiphile bilayer d 0 …”

“…Surfactant molecules can self-assemble into micelles, vesicles, lyotropic liquid crystals, and many other aggregates. , Lyotropic liquid crystals are between solid and liquid, including hexagonal liquid crystals, lamellar liquid crystals, and cubic liquid crystals. The lamellar liquid crystals have a unique double-layer structure, in which the layers can slide under an external force.…”

Scission energy and topology of micelles controlled by the molecular structure of additives

“…31–35 Various viscoelastic properties such as, storage and loss modulus, zero-shear viscosity and average breakage time as a function of salt concentrations, have been reported in these studies. Theoretical models 36–42 also have been developed recently to understand the role of additives in the scission energy, morphology and rheological properties of micellar solutions. However, more microscopic details such as effects of the hydrotropes on the micelle core structure and its consequence on the micelle scission energy are difficult to obtain from experiments and theoretical models.…”

Solvent-Directed Transformation of the Self-assembly and Optical Property of a Peptide-Appended Core-Substituted Naphthelenediimide and Selective Detection of Nitrite Ions in an Aqueous Medium

“…56 In general, it is not possible to study the properties of a hydrophobic NDI molecule in hydrophilic solvents and vice versa. However, an effective method for studying the hydrophobic molecule in a water medium can be accessed by their encapsulation within the hydrophobic region of a micelle 57,58 or within the lipid bilayer 59 and subsequently dispersing the micelle/lipid bilayer in the aqueous medium.…”

“…In general, it is not possible to study the properties of a hydrophobic NDI molecule in hydrophilic solvents and vice versa. However, an effective method for studying the hydrophobic molecule in a water medium can be accessed by their encapsulation within the hydrophobic region of a micelle , or within the lipid bilayer and subsequently dispersing the micelle/lipid bilayer in the aqueous medium. The molecule with a fluorescence property in the hydrocarbon solvent can be dispersed in the water medium by encapsulating it into the micelle, and it can be applied in bioimaging and sensing .…”