(235c) Modeling the Response of "Dual-Crosslinked" Functionalized Nanoparticles to Mechanical Deformation

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.