Surfactant–polymer interactions: molecular architecture does matter

Abstract

Polymer-surfactant mixtures are found in many industrial formulations, and hence there is a significant interest in understanding, at a molecular level, how the self-assembly of surfactant is affected by oppositely-charged polyelectrolytes (PEs). We use self-consistent field modeling and show that the modes of interaction of PEs strongly depend on the architecture of the PE on the segmental level. Hydrophilic cationic PEs with their charge proximal to the linear backbone are expected to bind electrostatically to the outsides of the coronas of the spherical micelles of anionic surfactants, such as sodium laureth sulphate (SLES). As a result, the surfactant aggregation number increases, but at the same time the colloidal stability deteriorates, due to bridging of the PEs between micelles. PEs with their charge somewhat displaced from the backbone by way of short hydrophobic spacers, are expected to be present inside a micelle at the core-corona boundary. In this case the aggregation number decreases, yet the colloidal stability is retained. Hence, SLES tends to remove hydrophilic PEs from an aqueous solution, whereas it solubilizes more hydrophobic ones. The binding isotherm shows that the uptake of PEs remains typically below charge compensation and in this case the spherical micelle topology remains the preferred state.

Mechanically Stretchable and Electrically Insulating Thermal Elastomer Composite by Liquid Alloy Droplet Embedment

“…For a TEC, the shape of the liquid alloy droplet fillers and the contact interface between liquid alloy fillers and the PDMS matrix can significantly influence heat transfer over the filler gaps and thus the thermal conductivity. To achieve better adhesion at the interface between the liquid alloy fillers and the PDMS matrix, an additional buffer interface material 43 or surface functionalization 44 can be introduced. This should be subjected to a further investigation in the future.…”

Mesoscopic simulation studies on the formation mechanism of drug loaded polymeric micelles

“…In particular, mesoscopic simulations are applied to explore the morphologic changes of complex systems and elucidate complex mechanisms [17,18]. The formation mechanism of drug delivery carriers in an aqueous environment can be investigated in greater detail through mesoscopic simulations than through experimentation [19]. Among usual mesoscopic simulation methods, for instance molecular dynamics (MD) simulation whose time scales are too short to observe the formation of the micelles, and the simulation at atom level is also very expensive [20][21][22], dissipative particle dynamics (DPD) which allows for a much larger time step and length scales is widely used in the simulation of coarse-grained models of fairly complex systems [23,24].…”

Physicochemical Aspects of the Performance of Hair-Conditioning Formulations

“…Nowadays, different theoretical approaches, mainly based on the use of mean-field self-consistent calculations, have been used for the in silico prediction of the performance of different model conditioning formulations [11,[71][72][73][74]. The results obtained following the abovementioned theoretical approaches are generally in good accordance with the experimental findings [7,45,46].…”