Collaborative Research: An Integrated Experimental/Computational Study of the Mechanics of Nanofiber Networks

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

This award supports research to characterize the effective mechanical strength and ductility of polymer nanofiber networks for nanofilamentous materials such as gels, rubber, tissue scaffolds, cellulose products and non-wovens. Although macroscale fiber networks are quite well understood, nanofibers behave differently from their macroscale counterparts due to the coupled effect of their outstanding ductility and strength that are not observed in microscale fibers, and the relatively strong adhesion between nanofibers. These two distinguishing features lead to currently unexplored opportunities for controlling and vastly improving the effective mechanical strength and ductility of polymer nanofiber networks. Ordered and random networks of nanofilaments composed of polymeric or biological materials are omnipresent in biological tissues, tissue scaffolds, biomedical implants, electrospun air filtration systems, cellulose products, etc. Undergraduate researchers will work with the faculty and graduate students to develop web-based, interactive educational classroom modules to introduce students to the concepts of fiber networks and design. The research focuses on regular and random quasi-2D nanofiber networks with bonded and non-bonded (cohesive) interactions between polymeric nanofibers, to identify ways for constructing networks with exceptional strength and toughness. To this effect, a tightly integrated experimental/computational research program will be followed in which the mechanical response of polystyrene (PS) and polyacrylonitrile (PAN) nanofibers (100-500 nm diameter), and the strength of bonded fiber interactions and adhesive PS-PS and PAN-PAN fiber contacts will be determined using novel experiments. The data will be employed to calibrate a computational model for the network mechanics, which will account for bonded, adhesive and topological interactions of nanofibers and will be used to determine the relative importance of these interactions in the overall mechanical behavior of networks with various network architectures and parameter sets. The model will be validated based on targeted experiments performed on regular and random fiber networks, and will be applied to perform optimization of the network structure for enhanced strength and toughness.