Kinetics of diffusionally induced gelation and ordered nanostructure formation in surfactant–polyelectrolyte complexes formed at water/water emulsion type interfaces

Chitosan-DNA Particles for DNA Delivery: Effect of Chitosan Molecular Weight on Formation and Release Characteristics

“…[1][2][3] Interestingly, interactions between oppositely charged surfactants and polyelectrolytes in aqueous solutions can lead to associative phase separation, where the concentrated phase assumes the form of a viscous liquid, gel, liquid crystal or precipitate. This behavior has previously been exploited to form gel particles, which have been prepared by dropwise addition of a solution of cationic polysaccharide (chitosan, N,N,Ntrimethylammonium derivatized hydroxyethyl cellulose (Amerchol JR-400 TM )) [4][5][6][7] to anionic (sodium dodecyl sulfate (SDS), sodium perfluorooctanoate (FC7)), and catanionic (cetyltrimethylammonium bromide (CTAB)= sodium perfluorooctanoate (FC7)) [8] surfactant solutions.…”

Diffusion driven layer-by-layer assembly of graphene oxide nanosheets into porous three-dimensional macrostructures

“…Decrease in growth rate of the GO/b-PEI layer with time is also clearly observed; this indicates that although the assembly is driven by the diffusion of b-PEI, other factors such as depletion of the reactants can influence the growth of the assembled structure. Similar diffusion-induced development of complex layer has also been observed during interactions between oppositely charged small molecules at liquid-liquid interfaces [32][33][34] ; however, the formation of a porous multilayered structure shown in Fig. 1 is quite unique, which we attribute to the relatively large size and highly anisotropic shape of the GO sheets.…”

DNA gel particles: An overview

“…Control over the transitions between these states allows exploitation of surfactant and polyelectrolyte mixtures in a wide array of commercial applications, such as drug delivery, cosmetic formulations, and rheological modification. There have initially been two separate reports of associative phase separation in surfactant and polyelectrolyte mixtures (where the polyelectrolyte undergoes a transition from an expanded to a collapsed state) that yields hollow surfactant/polyelectrolyte gel particles, with numerous potential applications in controlled encapsulation and release and separation processes [38][39]. This effect is achieved with a dropwise addition method [40][41][42] where drops of chitosan solutions are added to an oppositely charged surfactant solution [38][39].…”

“…There have initially been two separate reports of associative phase separation in surfactant and polyelectrolyte mixtures (where the polyelectrolyte undergoes a transition from an expanded to a collapsed state) that yields hollow surfactant/polyelectrolyte gel particles, with numerous potential applications in controlled encapsulation and release and separation processes [38][39]. This effect is achieved with a dropwise addition method [40][41][42] where drops of chitosan solutions are added to an oppositely charged surfactant solution [38][39]. Observations suggest that the gel formation process is diffusion limited, that the gel layer thickness is proportional to the amount of polyelectrolyte in solution, and that the gelled surfactant and polyelectrolyte complex is electroneutral [39].…”

“…This effect is achieved with a dropwise addition method [40][41][42] where drops of chitosan solutions are added to an oppositely charged surfactant solution [38][39]. Observations suggest that the gel formation process is diffusion limited, that the gel layer thickness is proportional to the amount of polyelectrolyte in solution, and that the gelled surfactant and polyelectrolyte complex is electroneutral [39]. 5 This behaviour has been exploited to form gel particles by dropwise addition of solutions of different cellulose-based polycations (chitosan, N,N,N-trimethylammonium derivatized hydroxyethyl cellulose (Amerchol JR-400)) [38][39][43][44] to anionic (sodium dodecyl sulfate (SDS), sodium perfluorooctanoate (FC7)) and catanionic (cetyltrimethylammonium bromide (C16TAB)/sodium perfluorooctanoate (FC7)) surfactant solutions [45].…”