||Wright-Patterson AFB, OH 454337817
Efficient materials design and development of tools for their damage prediction are crucial for multifunctional composites. Biomimetic design has opened up avenues for achieving extraordinary combinations of toughness and strength, similar to natural composites, although natural composites still surpass these properties. Key challenges include lack of understanding of the failure mechanisms in such composites and the influence of size, shape, and orientation of the nanofiller on toughening. There are still open questions about chemical structure and morphology around the interphase region and its influence on the mechanics. Overcoming these challenges requires careful design and a multidisciplinary approach combining synthesis, processing, characterization (across scales), and multiscale modeling. We are interested in understanding the failure mode from the nano- to higher scales, and the underlying processing structure-property relationship. Key interests include the biomimetic design of hierarchical structures; elucidating the fundamental principles of the underlying fracture mechanism based on chemistry and shape/size/distribution of the nanofillers; investigating corresponding electrical and optical properties; and establishing techniques to predict failure using molecular and mesoscale mechanics modeling. Techniques include bulk and surface spectroscopy, high-resolution X-ray micro-computed tomography, nanoscale chemical/physical/mechanical mapping, atomic force microscopy, electron microscopy, in-situ testing, and multiscale modeling.
Ao G, Nepal D, Davis VA: "Rheology of lyotropic cholesteric liquid crystal forming single-wall carbon nanotube dispersions stabilized by double-stranded DNA.” Rheologica Acta 55: 1-9, 2016
Jawaid A, Nepal D, et al: “Mechanism for Liquid Phase Exfoliation of MoS2.” Chemistry of Materials 28: 337-348, 2016
Park K, et al: "Engineering the Optical Properties of Gold Nanorods: Independent Tuning of Surface Plasmon Energy, Extinction Coefficient and Scattering Cross-Section.” Journal of Physical Chemistry C 118: 5918-5926, 2014
Biomimetic; Nanocomposite; Nanoscale imaging; Polymer; Mechanical properties; Spectroscopy; Fracture mechanics; Electro-optical properties; Multiscale modeling;