Adsorption of Mixtures of Poly(amidoamine) Dendrimers and Sodium Dodecyl Sulfate at the Air–Water Interface

Abstract

We relate the adsorption from mixtures of well-defined poly(amidoamine) (PAMAM) dendrimers of generations 4 and 8 with sodium dodecyl sulfate (SDS) at the air-water interface to the bulk solution properties. The anionic surfactant shows strong attractive interactions with the cationic dendrimers at pH 7, and electrophoretic mobility measurements indicate that the association is primarily driven by electrostatic interactions. Optical density measurements highlight the lack of colloidal stability of the formed bulk aggregates at compositions close to charge neutrality, the time scale of which is dependent on the dendrimer generation. Adsorption at the air-water interface was followed from samples immediately after mixing using a combination of surface tension, neutron reflectometry, and ellipsometry measurements. In the phase separation region for dendrimers of generation 4, we observed high surface tension corresponding to a depleted surfactant solution but only when the aggregates carried an excess of surfactant. Interestingly, these depleted adsorption layers contained spontaneously adsorbed macroscopic aggregates, and these embedded particles do not rearrange to spread monomeric material at the interface. These findings are discussed in relation to the interfacial properties of mixtures involving dendrimers of generation 8 as well as polydisperse linear and hyperbranched polyelectrolytes where there is polyelectrolyte bound to a surfactant monolayer. The results presented here demonstrate the capability of dendrimers to sequester anionic surfactants in a controllable manner, with potential applications as demulsification and antifoaming agents.

The Demulsification Properties of Cationic Hyperbranched Polyamidoamines for Polymer Flooding Emulsions and Microemulsions

“…As shown in Figure 6, to evaluate mutual adsorption, the metrological SLS solutions were mixed with 100 mg/L demulsifier (water-SLS-demulsifier system) and turbidity was measured using a wavelength of 450 nm optical density transmission [36]. Two different conditions were specified to clarify the interaction between the demulsifiers and the dispersed surfactants.…”

On the formation of dendrimer/nucleolipids surface films for directed self-assembly

“…Similar behavior has been found in mixtures consisting of PAMAM and the anionic surfactant SDS. 31 A slight excess of DLPNs is needed, especially for the mixtures containing DLPA, to form neutral complexes which is a result of the equilibrium between the bound surfactant and the free surfactant, which itself is affected by the solvent conditions. Additionally, the shi of the PAMAM/DLPA mobility towards higher bulk DLPN concentrations compared to PAMAM/DLPU indicates that the association in the bulk solution with the dendrimers depends also on the type of nucleoside head group.…”

“…30 All the mixtures were prepared immediately before the measurements in order to ensure that the samples were not depleted of material as it has been observed previously for other dendrimer/surfactant mixtures. 31 …”

Preparation of magnetic Fe3O4/P (GMA‐DVB)‐PEI/Pd highly efficient catalyst with core‐shell structure

“…In recent years, the fabrication and the application of linear‐dendritic organic materials have become a very hot research topic. And these materials have been widely applied in drug delivery, adsorption, catalysis, photonics, molecular imprinting, and so on, attributed to the unique spatial conformation and the large number of functional groups stemming from the branched segments . Of particular attention is that noble metal catalysts anchored onto the branched segments can well fulfill the high‐density loads.…”

“…And these materials have been widely applied in drug delivery, adsorption, catalysis, photonics, molecular imprinting, and so on, attributed to the unique spatial conformation and the large number of functional groups stemming from the branched segments. [13][14][15][16][17][18][19] Of particular attention is that noble metal catalysts anchored onto the branched segments can well fulfill the high-density loads. And moreover, the strong combination between these two parts endows the significant stability of noble metal catalysts.…”