Seminar 9/24/2014 - Tadanori Koga, Stony Brook University: New Paradigm for the Design of Polymer-Solid Interfaces
Abstract: Polymer thin films on top of impenetrable solids is of vital importance in many traditional technologies as well as new emerging nanotechnologies such as organic photovoltaics and biosensors. In this talk, I will focus on polymer-solid interfaces where irreversible polymer adsorption occurs regardless of the magnitude of solid-segment attractive interactions. In order to unveil the equilibrium conformations of adsorbed polymer chains, spin-cast homopolymer films prepared on Si substrates were used as models. The films were annealed at a high temperature to promote adsorption and ensure equilibrium and subsequently rinsed with a good solvent to remove non-adsorbed chains. A suite of surface sensitive techniques including grazing-incident x-ray/neutron scattering and atomic force microscopy were utilized. Firstly, I will present the unique nano-architectures and dynamics of the adsorbed chains and highlight the resultant long-range effects on the local structures and properties of the film. Secondly, I will discuss the unique adhesive property of the adsorbed chains that controls the thermodynamic stability of spin-cast films. Thirdly, I will also demonstrate the formation of the adsorbed layers in monolayer films of block copolymers, which would be a crucial parameter to control the orientation of the microdomain structures. Lastly, I will focus on geometric effects of solids on the nano-architectures by comparing with the adsorbed layers on nanoparticle surfaces.
Bio: Tad Koga is an associate professor in Chemical and Molecular Engineering Program at Stony Brook University. He received his Ph.D from Kyushu University, Japan in 1998 under the guidance of Prof. Takeji Hashimoto (Kyoto University, Japan). He is currently the spokesperson of the Advanced Polymers Beamline (X27C) at National Synchrotron Light Source and the research member of the Advanced Soft Material Beamline Consortium, Synchrotron Radiation Research Institute, SPring-8 (Japan). He received the NSF CAREER award for his work on green polymer surface processing using supercritical carbon dioxide in 2009.
All seminars are held on Wednesdays from 12:00 noon-1:00 p.m. in the Bowen Hall Auditorium Room 222. A light lunch is provided at 11:30 a.m. in the Bowen Hall Atrium immediately prior to the seminar.
Location: Bowen Hall Auditorium
Date/Time: 09/24/14 at 12:00 pm - 09/24/14 at 1:00 pm
Category: PRISM/PCCM Seminar Series