Spectroscopic Investigation of Electrospun Nanofibers

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My group studies the structure and properties of soft materials (polymers, supramolecular assemblies and molecular glasses) and develops advanced spectroscopy techniques (such as polarized Raman and time-resolved infrared spectroscopy). Our experience and world-leading infrastructure provide us a unique opportunity to make innovative contributions in the field of electrospinning. *** Electrospinning is an extremely popular method for producing nanofibers thanks to its experimental simplicity and amazing versatility. Electrospun fibers are currently used in selective membranes, tissue engineering and other biomedical applications, but there is a growing interest in applying them for technological applications in sensors, energy conversion, catalysis and opto-electronic devices. Unfortunately, our understanding of the structure and properties of nanofibers, and how they are affected by the electrospinning process, remains fragmentary. Molecular orientation is often invoked as a critical parameter but it is challenging to quantify. My group has recently demonstrated the power of vibrational spectroscopy at the individual fiber scale to do this quantification and answer other important questions in the field.*** In this context, my program seeks to understand and control the structure and properties of electrospun fibers using state-of-the-art vibrational spectroscopy. We will study five key aspects of electrospun fibers, with the specific objectives of: 1) Understanding molecular orientation in fibers and its impact on their properties; 2) Demonstrating and controlling disentanglement of polymer chains during electrospinning; 3) Enabling a deeper understanding of electrospinning through time-resolved infrared studies; 4) Understanding why and where polymorphs form during electrospinning; and 5) Understanding the effect of blending on fiber microstructure. To reach these ambitious objectives, we will use our workhorse Raman technique in combination with IR spectroscopy, including the first nanoIR instrument in Canada, and various complementary techniques.*** Our research is innovative and could not be conducted elsewhere in the world. It should greatly improve the current understanding of the structure in electrospun fibers and their unusual properties when they reach the nanoscale. It will allow confirming and explaining possibly transformative observations, such as partial disentanglement and polymorph formation. Our work will also lead to significant instrumental developments in vibrational spectroscopy that will be applicable to other fields of materials science. Overall, our work will improve our ability to optimize the properties of nanofibers and contribute to making their promising technological applications a reality.**