Abstract Details
| Influence of Particle-Polymer Affinity on Viscoelastic Properties of Hydrogel Nanocomposites | |
|---|---|
| Abstract ID | MAT-04 |
| Presenter | Masaki Yanagioka |
| Presentation Type | Poster |
| Full Author List | M. Yanagioka (1) , M. F. Toney (2) , C. W. Frank (1) |
| Affiliations | (1) Department of Chemical Engineering, Stanford University, Stanford, CA 94305 (2) Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, Menlo Park, CA 94025 |
| Category | Materials Science |
| Abstract | Both the nanoparticle distribution and the nanoparticle−polymer affinity influence the viscoelastic properties of nanocomposites significantly. However, these two parameters are closely coupled to each other, and evaluation of individual contributions to the mechanical properties allows us to expedite efficient development of nanocomposites with desirable properties. To separate these two effects, we utilized a crystalline colloidal array that was encapsulated within a polymer matrix such that particle agglomeration was essentially eliminated. We then investigated how the nanoparticle−polymer affinity relates to the mechanical properties of the nanocomposite by comparing the silica and polystyrene nanoparticles. A smaller viscoelastic loss for the polystyrene-filled nanocomposite was observed compared to the silica-filled nanocomposite. To understand this difference between these two systems, the surface roughness of the particles within the polymer matrix and the molecular conformation of the interfacial layer between the polymer and the nanoparticles were characterized by synchrotron small-angle X-ray scattering and quartz crystal microbalance, respectively. On polystyrene particles, the surface roughness was larger, and the adsorbed polymer assumed a flat conformation. Consequently, the mobility of the adsorbed polymer was reduced compared to the one on silica particles. This reduced mobility explains a smaller viscoelastic loss for the polystyrene-filled nanocomposite. |
| Footnotes | |
| Funding Acknowledgement | We thank Nippon Shokubai Co. Ltd. for their gift of the silica particle suspension. This work is supported by the Center on Polymer Interfaces and Macromolecular Assemblies (CPIMA), which is sponsored by the NSF−MRSEC program. M.Y. is grateful for support in the form of a fellowship from Bridgestone Corp. |