Preparation of monodisperse polyelectrolyte complex nanoparticles in dilute aqueous solution
Polyelectrolyte complexes (PEC) have been obtained by a fast ionic exchange reaction between polyelectrolytes bearing oppositely charged groups. Depending on the nature of the polyelectrolyte components and the mixing conditions, highly aggregated PECs with no phase separation during complexation can be prepared. PEC formation in diluted solutions and at non-stoichiometric mixing ratios results in homogeneous systems of sphere-like particles with charge-neutralized cores and shells of the excess component, which stabilize the particles against further coagulation. From the viewpoint of applications, such stable colloidal dispersions of PEC particles possess a high potential as carrier systems for organic molecules or as modifying solutions in coating processes. The aim of this work was to prepare homogeneous solutions of PEC particles characterized by a polydispersity index of <0.05. This could be realized by controlling the total polymer concentration and the mixing conditions of the oppositely charged polyelectrolytes. The effects of polymer structure, chain length, and charge distribution were also investigated. In this study poly(diallyldimethylammonium chloride), a linear polycation and poly(ethyleneimine) hydrochloride, a branched polycation were used in combination with the weak polyanion poly(maleic acid-co-propene). In addition, it was desirable to control the placement of the mono-sized PEC particles on modified silicon wafer.
KeywordsPolyelectrolyte complexes Colloidal dispersion Mono-sized complex particles Interacting polymers: poly(diallyldimethylammonium chloride) Poly(ethyleneimine) Poly(maleic acid-co-propene)
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