259234 Modeling the Response of "Dual-Crosslinked" Functionalized Nanoparticles to Mechanical Deformation

Tuesday, October 30, 2012: 9:20 AM
Butler West (Westin )
Balaji Iyer1, Isaac Salib1, Victor. Y. Yashin1, German Kolmakov2, Krzysztof Matyjaszewski3 and Anna Balazs1, (1)Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, (2)Physics, New York City College of Technology, Brooklyn, NY, (3)Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA

We investigate the role of stretchable polymeric arms and force-dependent kinetics of dual cross-links on the mechanical response of a network formed by polymer-grafted nanoparticles (PGN). Each of the individual particles of the network is composed of a rigid core and a corona of grafted polymeric arms with functionalized end groups that can form stable and labile bonds. The presence of both the labile and stable bonds leads to a "dual-crosslinked" system. The overlap of the coronas of adjacent particles enables interaction between functionalized end groups that lead to the formation of the nanoparticle network. Interaction between polymer-coated colloids is combined with the Bell model for rupture and formation of bonds to model the interaction of array of particles. The mechanical response of the network is captured through the stretching and the force-dependent kinetics of the dual cross-linked polymer arms in the network. We show that the presence of stretchable arms allows for rearrangements leading to increases in the strength and ductility of the PGN network. We also show that the force-dependent kinetics of labile bonds modifies the initial mechanical response, while the stable bonds determine the ductility of the network.

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See more of this Session: Polymer Networks and Gels I
See more of this Group/Topical: Materials Engineering and Sciences Division