pH-Responsive Electrospun Nanofibers and Their Applications

Electrospun nanofibrous membranes offer superior properties over other polymeric membranes not only due to their high membrane porosity but also due to their high surface-to-volume ratio. A plethora of available polymers and post-modification methods allow the incorporation of "smart" responsiveness in fiber membranes. The pH-responsive property is achieved using polymers from the class of polyelectrolytes, which contain pH-dependent functional groups on their polymeric backbone. Electrospinning macroscopic membranes using polyelectrolytes earned considerable interest for biomedical and environmental applications due to the possibility to trigger chemical and physical changes of the membrane (swelling, wettability, degradation) in response to environmental pH-changes. Here, we review recent advancements in the field of electrospinning of pH-responsive nanofiber materials. Starting with the chemical background of pH-responsive polymers at the molecular level, we highlight the material-property transformation upon pH-change at the macroscopic membrane level and, finally, we provide an overview of recent applications of pH-responsive fiber membranes.