ChBE Seminar Series–Dr. Peter Green
In addition to its annual lectures, ChBE hosts a weekly seminar throughout the year with invited lecturers who are prominent in their fields. Unless otherwise noted, all seminars are held on Wednesdays in the Molecular Science and Engineering Building ("M" Building) in G011 (Cherry Logan Emerson Lecture Theater) at 4:00 p.m. Refreshments are served at 3:30 p.m. in the Emerson-Lewis Reception Salon.
Self-assembly and physical properties of polymer metallic nanoparticle thin film systems
Important questions regarding control of the structure and properties of the technologically important class of materials, generally identified as polymer nanocomposites (PNCs), remain even after more than two decades of research. PNCs, involving mixtures of polymers with particles of nano-scale dimensions, exhibit diverse functional properties, based on the molecular characteristics of the polymer and the size, dimension and chemistry of the nanoparticles (graphene, quantum dots, nanorods, clays, fullerenes and metallic nanocrystals). PNCs are used for applications that range from structural and biomedical to electronic and optical. The primary challenge associated with the use of these systems is that the properties are unusually sensitive to the nanoparticle size and spatial distribution, and a combination of entropic and enthalpic interactions, which are often difficult to control. A unified picture of how various competing interactions at the nanoscale determine the structure and properties of PNCs remains elusive.
In this presentation we show that a promising strategy for controlling the spatial distribution of nanoparticles within a polymer host, and hence the properties, involves grafting chains onto the surface of metallic nanoparticles of varying sizes. We have developed rules to design and to fabricate thin films of different morphologies of this class of PNCs. I will present: (1) examples of phase diagrams of thin film polymer/nanoparticle systems; (2) self-assembly of nanoparticles in homopolymers and block copolymers; (3) strategies to “tailor” the refractive index, and surface plasmon phenomena, of thin film PNCs.