Polyelectrolyte Nanofibers

This chapter is devoted to polyelectrolytes (PEs), which possess macromolecules with a substantial part comprised of ionic or ionizable functional groups. Solutions of PEs reveal non-trivial physical phenomena when such functional groups are ionized under dissociation of counterions. Accordingly, electrostatic interactions between PE charges and dissociated counterions in solution, or in complex with another PE suspended in the same electrolyte reveal unexpected and attractive properties. As a result, conformations and dynamics of such PEs in solution are significantly affected by electrostatic interactions with the other PEs of the same or an opposite polarity. Especially interesting for applications are macromolecular polyelectrolyte complexes (PECs) resulting from the association of oppositely charged PEs. Polyelectrolytes can be electrospun to form nanofibers and nanofiber membranes. Electrospinning of polyelectrolytes is described here in detail, including the unusual physical properties of the resulting nanofibers and their internal structure. The deformable polyelectrolyte fibrous membranes can sustain an electro-osmotic throughflow and serve as a key element of artificial dynamically-tunable responsive malleable surfaces of the type of those considered in Sect.  1.3.6 in Chap. 1 .