Interparticle Interactions in Dilute Solutions of Polyelectrolyte Complex Micelles

Hao Wu, Jeffrey M. Ting, Thomas M. Weiss, Matthew V. Tirrell

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The application of dilute solutions of polyelectrolyte complex (PEC) micelles for delivering therapeutic nucleic acids into disease sites has gained momentum. This Letter reports a detailed characterization of PEC micelles in dilute solutions including their internal structures and the determination of the interparticle interactions. The polymer concentration ranges from 0.1 to 0.5 wt %, a regime where micelle-micelle interactions are infrequent. We employ synchrotron small-angle X-ray scattering (SAXS) to simultaneously probe the morphology, internal structure, and radius of gyration (Rg) of the self-assemblies formed by charged diblock polyelectrolytes and homopolyelectrolytes. The emerging appearance of the structure factor in SAXS profiles with the increasing polymer concentration demonstrates the presence of the repulsive intermicellar correlations, which is further confirmed by the differences between the "reciprocal Rg" estimated by Guinier approximation and the "real space Rg" determined by pair distribution functions. We find that the soft corona chains tethered on the surface of phase-separated complex domains are compressed when micelles come close to the point where a hard-sphere interaction takes over. These findings contribute to the fundamental understanding of the structure and space-filling constraints in the complexation-driven self-assemblies and advance the rational design of cationic polymer-based nonviral gene delivery vectors.

Original languageEnglish (US)
Pages (from-to)819-825
Number of pages7
JournalACS Macro Letters
Issue number7
StatePublished - Jun 19 2019
Externally publishedYes

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Copyright © 2019 American Chemical Society.


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