Prediction of Polyelectrolyte Complex Stoichiometry for Highly Hydrophilic Polyelectrolytes

Abstract

The interaction between two hydrophilic polyelectrolytes of opposite charges was investigated using poly­(l-lysine) (PLL) as the polycation and a library of copolymers of acrylamide and 2-acrylamido-2-methyl-1-propanesulfonate (P­(AM-co-AMPS)) with various chemical charge densities as polyanions. The formation of polyelectrolyte complexes (PECs) was comparatively studied by varying different parameters, such as the mixing order, the P­(AM-co-AMPS) chemical charge density and the initial polycation to polyanion molar ratio. PECs were then characterized in terms of charge stoichiometry and of stability toward ionic strength. The results showed a strong dependency of precipitated PEC stoichiometry on the P­(AM-co-AMPS) chemical charge density and the initial polycation to polyanion molar ratio. In contrast, PEC stoichiometry was not affected by the mixing order of the two polyelectrolyte partners. A general rule capable of predicting the PEC stoichiometry is proposed.

Supramolecular Self‐Assembly of DNA with a Cationic Polythiophene: From Polyplexes to Fibers

“…Interestingly, the free polycation concentration at equilibrium in the mixture allows determining the average number of polycation chains per DNA chain =341 corresponding to a positive to negative charge ratio of n + /n − =5.3, which means that the polyplex is highly positively charged. This finding is in agreement with the general rule recently enounced about the overall charge of polyelectrolyte complexes stating that if the polyelectrolyte of highest charge density between the two partners is introduced in excess in the mixture, the complex should have the same charge as this polyelectrolyte (here the polycation). Reversely, if the polyelectrolyte of highest charge density is introduced in default in the mixture, the complex should be stoichiometric (neutral, i. e. n + /n − =1).…”

Effect of Dendrigraft Generation on the Interaction between Anionic Polyelectrolytes and Dendrigraft Poly(l-Lysine)

“…Random copolymers of acrylamide and 2-acrylamido-2-methyl-1-propanesulfonate (PAMAMPS) with chemical charge densities f of 30% and 100% were synthesised by free radical copolymerization as described by McCormick et al [ 37 ]. The details of the synthesis are reported elsewhere [ 38 ] and briefly described in the Supplementary. DP w of PAMAMPS 30% (respectively 100%) were 3689 (respectively 4166) as obtained by Size-Exclusion Chromatography Coupled with Multi-Angle Laser Light Scattering (SEC-MALLS) and published elsewhere [ 38 ].…”

Separation and Characterization of Highly Charged Polyelectrolytes Using Free-Solution Capillary Electrophoresis

“…The mean composition of the copolymer f measured using proton NMR (3.75 g/L polymer solution in D 2 O) was close to the monomer feed compositions, indicating high conversion. The average molecular masses of the PAMAMPS were evaluated using size-exclusion chromatography coupled with multi-angle laser light scattering (SEC–MALLS), and ranged between 3 × 10 5 and 10 6 g/mol [21]. For such high molar masses, the PE electrophoretic mobility is independent of the molar mass (free-draining behavior [8,12,22]).…”

“…For such high molar masses, the PE electrophoretic mobility is independent of the molar mass (free-draining behavior [8,12,22]). For more details on the synthesis and characterization of the PAMAMPS used in this work, the reader can refer to Reference [21].…”