Nanofibers – extremely thin strands of polymer material – are finding new and expanded uses in consumer products, in industry and in the medical field. These applications range from highly absorbent textiles, wound dressing materials, filters for water, air and oil, and drug delivery materials. Researchers at CLiPS (NSF Center for Layered Polymeric Systems) headquartered at Case Western Reserve University have developed an improved way of producing nanofibers using microlayer extrusion. Up until this discovery, nanofibers have been produced almost exclusively by electrospinning, a process that employs toxic organic solvents. The fibers produced at CLiPS by multilayer extrusion may have equivalent diameters as small as 10 to 100 nanometers. The diameter of a human hair, by contrast, is 100 microns – which equals 100,000 nanometers. These fibers have other special characteristics in addition to being produced without the use of solvents. Because the fibers are rectangular or ribbon-shaped rather than cylindrical, they have greater surface area relative to their overall size, and have shown greater mechanical performance characteristics than conventional fibers. These qualities make the fibers safer for the environment, more effective than conventional fibers, and less expensive to produce. CLiPS researchers produce the fibers by two methods. In the first example, vertical polymer components are layered between a solid polymer separator. The layers go through a multiplier to create many very thin layers. One of the polymers is water soluble. When the resulting multilayered film is placed in water, individual nanofibers remain. In the second technique, two different polymers are layered together horizontally. They also go through a multiplying process. In this instance the layers are cut vertically when they are still soft, and then extruded as a composite. The two polymers in the composite are separated and may be stretched to orient and strengthen the resulting fibers. New Nanofibers Using Microlayer Extrusion Eric Baer, Case Western Reserve University, DMR Air filter Separated into Nanofibers Vertical layers with solid layers in between - delaminated Multi-layered material Melt-cutting die Production Method 1 Production Method 2 Applications Special purpose textiles Wound dressings Filters Composite

New Nanofibers Using Microlayer Extrusion Eric Baer, Case Western Reserve University, DMR CLiPS REU Program Immerses Undergraduates in Research The REU program at CLiPS which features an intensive 10- week long summer program in engineering research is an important component of the STEM pipeline for CLiPS partner institutions. It is also an important vehicle for broadening participation in STEM education. The REU program draws from a national audience, with priority given to undergraduates at CLiPS partner and affiliate schools. This year, the REU program accepted students from 14 schools, including the 4 students from the new CLiPS HBCU affiliates. In addition, this year’s class featured 10 women (42%) and 9 members from under-represented minorities (45% - 4 students were undeclared). Historically 10 students have entered graduate programs at CWRU after their REU experience. These figures underscore the importance of the REU program in furthering our diversity efforts.