ChBE Seminar Series: Saad Khan
Tuesday, November 20, 2007
11:00 a.m.-12:00 p.m.
Room 2110, Chemical & Nuclear Engineering Bldg.
Professor Srinivava Raghavan
Functional Nanofibers via Electrospinning: From Coatings to Biomedical Therapeutics
Presented by Professor Saad Khan
Department of Chemical and Biomolecular Engineering
North Carolina State University
Nanofibers produced via electrospinning present a promising avenue for developing novel nanomaterials with well-defined functionalities. Their very high surface to volume ratio, arising from typical diameters between 10-500 nm, render them as an excellent source for developing functionalized materials for many applications such as membrane technology, drug delivery, filtration devices and tissue scaffolds. In this work we discuss fabrication of novel materials, and approaches to overcome some of the limitations associated with developing these functional nanofibers using electrospinning. As such, the presentation will have two components.
In the first part, we will examine a novel one-step process to fabricate metal nanoparticles (NP)-templated polymer nanofibers via solution electrospinning. The system has the potential as building blocks for fabricating functional fabrics with antimicrobial and catalytic properties for biomedical, filtration, sensor and catalytic applications. The effects of metal NP incorporation, electrospinning and polymer solution parameters, and nanoparticle and nanofiber morphologies are studied using imaging, materials characterization and rheological techniques.
A recurring issue in the area of electrospinning of nanofibers is the lack of spinnability of polymers, at lower concentrations to achieve smaller fiber diameters. In this part, we will discuss how we can improve the spinnability of these polymer systems by incorporating a unique class of polymers known as associative polymers. Our results show that addition of associative polymers to polymer solutions, otherwise not easily electrospinnable, leads to significant changes in viscosity and viscoelasticity. These rheological changes translate to bead-free and uniform final nanofiber morphology as well as reduced fiber diameter. This concept of using associative polymers is further extended to other associative polymers as well as other polymer systems which are not easily electrospinnable.