Conformation of a single polyelectrolyte in poor solvents

Area of Science:

• Polymer Science
• Biophysics
• Theoretical Chemistry

Background:

• Understanding polyelectrolyte (PE) conformation is crucial for polymer science and protein folding/aggregation.
• Existing theories and experimental data on PE structures in poor solvents require further refinement.

Purpose of the Study:

• To develop a theory incorporating electrostatic interactions into self-consistent field theory for PEs.
• To investigate the conformational behaviors of single PEs in poor solvents.
• To predict and characterize novel PE structures.

Main Methods:

• Systematic inclusion of electrostatic interactions into self-consistent field theory for polymers.
• Theoretical modeling of single polyelectrolyte chains in poor solvents.

Main Results:

• Predicted spherical globules (Sph) can elongate to pearl-necklace (PN) structures or flatten into novel biconcave red cell and toroid shapes.
• Identified PN structures as stable, while biconcave and toroid structures are metastable.
• Demonstrated that cylindrical globules are unstable.
• Observed less pronounced PN signatures compared to other theories, aligning with simulations and experiments.
• Revealed discontinuous Sph-to-double PN transitions and continuous transitions between adjacent PN structures.
• Found that string width decays with increasing backbone charge fraction, unlike thermal blobs.

Conclusions:

• The developed theory accurately predicts PE conformational transitions and identifies novel structures.
• The findings enhance understanding of polymer behavior in solution and have implications for protein folding studies.
• The theory provides a framework for further investigations into polyelectrolyte complex systems.