Complex coacervation was achieved using a ternary mixture of polymers by combining poly (allylamine) (PAH) or poly (ethylenimine) (PEI) with poly (acrylic acid) (PAA) and poly (N, N-dimethylaminoethyl methacrylate) (PDMAEMA). We performed a systematic investigation into the effect of mixing ratio, salt concentration and pH on these ternary coacervates. Turbidity and microscopy demonstrated that ternary coacervates form over a broader range of mixing ratios compared to the base PAA / PDMAEMA system. An enhanced resistance to salt was observed for ternary coacervates, demonstrated by the shift of the critical salt concentration of coacervate to solution boundary at higher salt concentrations. The shift of the critical salt concentration and its dependence on pH value were rationalized by using the Voorn-Overbeek model. The ternary system containing branched PEI showed a considerable difference in salt resistance, due to the dramatic change in the charge density of the polyelectrolyte at a specific pH range (6-8). Rheological analysis demonstrated that salt affects the relaxation time and viscoelastic behavior of ternary coacervates. Notably, relaxation curves shifted to lower relaxation times at a much higher salt concentration in ternary coacervates, due to their highly packed polymer network. Zeta potential measurements revealed that the stability of ternary coacervate droplets is also affected by changes in mixing ratio, salt and pH. Generally, ternary coacervates maintain the characteristics and tunability of typical binary coacervates. However, the choice of the third component is important, as it can significantly affects the response and material properties of the coacervates.

Ternary, tunable polyelectrolyte complexes driven by complex coacervation

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.