- Benjamin Wang
- Doctoral Candidate, Chemical Engineering
- Thesis:The effect of interfacial thermodynamics on the rheological properties of nanostructured polymeric composites formed by multilayer coextrusion
- co-advised by Gareth McKinley, Dept. of Mechanical Engineering
- B.S. Chemical Engineering, Stanford University, 1998
- Email: firstname.lastname@example.org
- Phone: (617) 253-6477
- Office: 66-353
Polymer composites are widely used in industrial and consumer applications for enhancement of mechanical properties, chemical resistance and optical properties. More recently chemically heterogeneous macromolecules, known as block copolymers, have attracted increasing interest because of their ability to self assemble into periodic lamellar morphologies. We utilize multilayer coextrusion, an advanced polymer processing technique to generate comparable nanometer thick lamellar structures. This technique does not rely on equilibrium phase separation to assemble the structure but rather employs a series of processing dies to create the layers through forced assembly. Many combinations of polymers can be coextruded to generate multilayered films and sheets making this a flexible technique for fabricating polymeric lamellar nanostructures.
Materials generated through multilayer coextrusion can and have been used for barrier applications, mechanical property enhancement, and complex optical interference stacks. When the number of layers becomes very large, the individual layers become very thin, and a large amount of interface is generated. While this can result in the development of interesting materials nanocomposites with meritorious properties, we are interested in using coextruded multilayers as a platform for investigating interfacial properties between polymers. By varying the number of layers in our system, we can quantitatively tailor the amount of interface in our material. As an example our investigations aims to experimentally determine the correspondence between the thermodynamic interactions between partially immiscible homopolymers and the bulk rheological properties of multilayers. We compare these results to existing scaling theory. We anticipate that a greater understanding of these properties will allow us to achieve a greater understanding of polymer-polymer interactions in confined, highly interfacial conditions.