Triblock Polyelectrolyte Synthesis: Guanidinium and sulfonate functionalized poly(ally glycidyl ether)-b-poly(ethylene glycol)-b-poly(ally glycidyl ether) (PAGE-PEO-PAGE) were synthesized following previously published anionic polymerization protocols . Poly(ethylene glycol) (PEO, Mn = 20,000 g•mol -1 ) was dried in a vacuum oven at 25 °C for one day before use. Allyl glycidyl ether (AGE) was mixed with calcium hydride, stirred overnight to remove trace amounts of water, and degassed by three cycles of freeze-pump-thaw, followed by distillation. All anhydrous reagents were transferred into a glove box under a dry argon atmosphere. An appropriate amount of PEO was dissolved in 50 mL anhydrous THF and titrated with potassium naphthalenide (0.4 M in anhydrous THF) until the solution turned light green. Then, AGE was added, and the reaction mixture was stirred at 45 °C for 48 h. The polymerization reaction was terminated by the addition of degassed methanol. The product was precipitated in hexane, filtered, and dried under vacuum prior to further functionalization. The degree of polymerization of the PAGE blocks was calculated from the relative peak intensities in the NMR spectra, yielding PAGE30-PEO455-PAGE30.