Salt Effect on Polymerizable Vesicles of Allyl Dodecyl Dimethylammonium Bromide and Sodium Dodecyl Sulfonate in Aqueous Solution

Abstract

Polymerization reactions in vesicles are known to fix the vesicular structure to provide stabilized hollow colloidal nanoparticles used as biological membrane models, drug delivery vehicles, or templates for the synthesis of nanostructures. As a precursive work of polymerization directly from vesicles, a polymerizable surfactant, allyl dodecyl dimethylammonium bromide (ADDB) was synthesized, and spontaneous stable vesicles were formed from aqueous solutions of ADDB and sodium dodecyl sulfonate (SDS) in equimolar composition. The aqueous mixture of ADDB/SDS could form homogeneous solutions even at a high surfactant or sodium bromide (NaBr) concentration. Before polymerization, salt effect on the polymerizable vesicles was investigated by using dynamic light scattering (DLS) and freeze-fracture transmission electron microscopy (FF-TEM) measurements. It was interestingly revealed by the DLS method that the vesicle size increased from 83 nm in a salt-free solution to 250 nm with increasing the salt concentration to 250 mmol/L, but decreased from 250 to 180 nm with increasing the salt concentration to 1000 mmol/L. The same meaningful trend was disclosed by the FF-TEM measurements that when NaBr concentration was below 150 mmol/L the dispersed individual vesicle size was about 70 nm but it decreased to 20 nm while the NaBr concentration was above 400 mmol/L. The causation of increment of average aggregate radius can be attributed to the fusion and flocculation of vesicles observed clearly under a TEM imagine. The decrease of vesicle size results from the fact that, at a high salt concentration, electrolyte screens the interaction between the charged head groups, thus entropic increase drives big vesicles to decrease to small ones.

Synthesis of Amphiphilic Star Block Copolymers and Their Evaluation as Transdermal Carriers

“…The use of covalently reinforced micelle-like carriers has potential to circumvent these complications by removing the dependence on dynamic equilibrium. Whereas a number of researchers have demonstrated the covalent cross-linking of preformed liposomes − or polymer micelles, − an attractive alternative approach is to construct micelle-like macromolecules “de novo” in which multiple amphiphilic component are synthesized covalently attached to form amphiphilic star polymers. Whereas smaller stars still are expected to be susceptible to disaggregation, their CMCs should be drastically reduced.…”

Chaotropic Salt Dispersion Enables Room-Temperature Synthesis of High-Purity Polyvinyl Butyral

“…However, these surfactants can become permanently entrapped or entangled within the PVB granules. 21 The residual surfactants undermine hydrophobic interactions, leading to a decline in the strength and cohesion of the PVB membranes. Consequently, a massive volume of water is required for PVB rinsing (1 ton of PVB resins consumes 100 tons of water or even more), 18 resulting in the generation of significant waste emissions.…”

“…Detailed information pertaining to this approach can be found in the "PVB Synthesis with Sodium Dodecyl Benzene Sulfonate" SI section, along with Video S1, in accordance with prior literature references. 21,27 The produced PVB is labeled as SDBS-B. Note that we designed the synthesis protocol using SDBS to compare it with that using NaSCN.…”