Polyelectrolytes are long, chain-like molecules with repeating charged units. These molecules are widely used in various fields, including the biomedical and energy industries. The self-assembly behavior of polyelectrolytes is crucial for their applications.
According to the classical theory, polyelectrolytes in an aqueous environment form complexes, called polyelectrolyte complexes (PECs), through electrostatic interactions between the charged units. The size, structure, and properties of PECs depend on various factors, including the charge density and concentration of the polyelectrolytes.
The team led by Professor Jean-Francois Joanny, Professor David Morse, and Professor Nathalie Duru developed a new theoretical framework that challenges this classical view. The key insight is that polyelectrolyte self-assembly is driven not only by electrostatic interactions but also by the excluded volume effect.
Excluded volume effect refers to the fact that two objects cannot occupy the same space at the same time. In the case of polyelectrolytes, the excluded volume effect arises from the fact that the molecules are long and flexible.
The team showed that the excluded volume effect can significantly affect the self-assembly behavior of polyelectrolytes, leading to the formation of different types of structures, such as clusters and networks, rather than the traditional PECs.
The theory is consistent with recent experimental observations and provides a more complete understanding of polyelectrolyte self-assembly. The findings could lead to the development of new materials with tailored properties for various applications.
