Paper Number
PO99
Session
Poster Session
Title
Decoupling polymeric and colloidal contributions to the rheology of self-suspended grafted nanoparticle melts
Presentation Date and Time
October 17, 2018 (Wednesday) 6:30
Track / Room
Poster Session / Woodway II/III
Authors
- Parisi, Daniele (FORTH-IESL, Materials Science and Technology-University of Crete)
- Buenning, Ellie (Columbia University)
- Benicewicz, Brian (University of South Carolina)
- Kumar, Sanat (Columbia University)
- Vlassopoulos, Dimitris (FORTH-IESL, Materials Science and Technology-University of Crete)
Author and Affiliation Lines
Daniele Parisi1, Ellie Buenning2, Brian Benicewicz3, Sanat Kumar4, and Dimitris Vlassopoulos1
1Materials Science and Technology-University of Crete, FORTH-IESL, HERAKLION, Greece; 2Columbia University, New York, NY; 3University of South Carolina, Columbia, SC; 4Columbia University, New York, NY
Speaker / Presenter
Vlassopoulos, Dimitris
Text of Abstract
Using a series of well-characterized polymer-grafted silica nanoparticles with the same hard core size and grafting density, we investigate their linear viscoelastic response in the melt state as function of increasing molar mass of the grafted chains, i.e., with decreasing core volume fraction. We identify two modes of relaxation, a faster one associated with the grafted chains and a slower one reflecting the overall nanoparticle hopping. These modes are quantified by means of tube and mode coupling theory modeling, respectively, by accounting for the molecular features of the particles and the estimated stretched inner part of the grafted layer, where interpenetration with chains from other nanoparticles is virtually impossible. Consequently, the two modes can be decoupled and, importantly, the transition from polymer- to colloid-dominated response is identified. Further, we discuss the respective signatures in nonlinear shear and focus on the yielding process in an attempt to provide material parameters for tailoring the response of such soft composites.