Paper Number
PS5
Session
Polymers in Solution
Title
Transport of interacting nanoparticles in complex polymeric solutions
Presentation Date and Time
October 15, 2018 (Monday) 11:30
Track / Room
Track 4 / Post Oak
Authors
- Poling-Skutvik, Ryan (University of Houston, Chemical and Biomolecular Engineering)
- Slim, Ali (University of Houston, Chemical and Biomolecular Engineering)
- Krishnamoorti, Ramanan (University of Houston, Chemical and Biomolecular Engineering)
- Conrad, Jacinta C. (University of Houston, Chemical and Biomolecular Engineering)
Author and Affiliation Lines
Ryan Poling-Skutvik, Ali Slim, Ramanan Krishnamoorti, and Jacinta C. Conrad
Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204
Speaker / Presenter
Conrad, Jacinta C.
Text of Abstract
Transport of nanoparticles through complex fluids is essential for environment remediation, nanocomposite processing, and targeted drug delivery. Because nanoparticles are of comparable size to the heterogeneities present in many complex fluids, their dynamics cannot be described through the framework of microrheology but rather decouple from the bulk fluid properties. Indeed, nanoparticles can transport many orders of magnitude faster than expected when coupled to complex fluid relaxations on similar length scales, or much more slowly than expected when physically obstructed. Interactions between the nanoparticles, arising from high particle densities and/or chemical surface modifications, can further modify their transport properties. To understand the underlying physics of transport in this size regime, we measure the dynamics of surface-modified silica nanoparticles moving through polymer solutions, which serve as model complex fluids with well-controlled and tunable heterogeneities, using x-ray photon correlation spectroscopy. Electrostatic charges lead to long-range interactions between the particles in organic solvents without disrupting the structure or dynamics of the surrounding polymer solution. The long-range interparticle interactions slow nanoparticle dynamics across the interparticle distance, even though the nanoparticle dynamics are subdiffusive and coupled to the polymer relaxations. Grafted polymers help to stabilize the nanoparticles in complex fluids and lead to soft physical interactions between the grafted particles and the surrounding polymer chains, with implications for their transport behavior. Our work illustrates that modifying the particle surface chemistry grants excellent control over the transport properties of nanoparticles through complex media.