On the occasion of the 50thanniversary of Macromolecular Science and Engineering program at Case Western Reserve University it seems appropriate to highlight scientific impacts this program had on the current advances in materials science as well as on related fields in the context ofthe recent most emerging discoveries.  Over the last 50 years fundamental discoveries formulated a foundation for many current and future discoveries. The emerging field of materials science in general, and polymer science in particular, that our research group is involved in are stimuli-responsive and self-healing polymeric materials. Recent studies have demonstrated that using an orchestrated choice of reactive components in designing polymeric matrices it is possible to achieve self-repairable networks [1,2] or formulate multi-component materials with self-healing properties [3]. Numerous experiments also suggested that controllable localized network heterogeneities play an essential role in stimuli-responsive behavior of polymer networks. In the context of physico-chemical events responsible for repair processes, this presentation will focus on spectroscopic evidence and thermodynamic considerations of self-healing and the role of the recoupling self-healing lattice model enabling to estimate the contributions of localized configurational changes as well as chemical reactions occurring during self-healing to the Gibbs free energy. As chains undergo transitions from non-equilibrium to equilibrium Gaussian states during self-healing, the magnitude of entropic and enthalpic contributions undergoes dynamic changes, and localized heterogeneities involving reformation of covalent bonding, coordination, and supramolecular chemistries play an essential role in this remodeling process. An interplay of orchestrated supramolecular and covalent bonding will be discussed in the context of IR and Raman imaging of thermoplastic and thermosetting polymers.References: (1) Ghosh, B., Urban, M.W., Science 323  , 1458, 2009; (2) Yang, Y., Urban, M.W., �Healable Polymer Systems,� Ed. Wayne C. Hayes, Royal Society of Chemistry, 2012.

Role of localized heterogeneities on stimuli-responsiveness and self-healing in polymers

245th National Meeting (2013)

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