NER: Engineering Stable Nanoscale Conducting / Insulating Polymer Interfaces: Combinatorial Exploratory Research

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Thin films can become unstable at thicknesses below 100 nm, due to attractive van der Waals (VDW) interactions. This problem is particularly severe in conducting and semiconducting polymers, which have large Hamaker constants. VDW instability results in dewetting and must be avoided in nanoscale film processing. Yet, robust methods for preventing VDW instability in these systems have not emerged. A failure to develop strategies to control instability places severe limits on the use of conducting polymer thin films at nanoscale dimensions. To address this critical limitation, this research will explore an innovative method to stabilize nanoscale conducting / insulating film bilayers. Research Plan and Significance. Nanoscale conducting polymer devices require multilayered junctions of conducting / insulating interfaces. VDW instability is likely to occur at these junctions due to Hamaker constant mismatch. This research will develop an exploratory method to prevent VDW instability at polymer bilayer conductor / insulator interfaces. The lack of previous research and theory on nanoscale conductive polymer wetting stability leads to the exploratory, high-risk nature of this project. The risk is increased by the experimental difficulty in maintaining consistent substrate chemistry over the many samples needed to test hypotheses. To overcome this limitation in experimental efficiency, a high-throughput measurement method will be used for feasibility studies of bilayer stability. Specific Aims: 1) The parameters required to prevent VDW instability will be determined for a model bilayer thin film system: poly(3-undecybithiophene) (PUBT) / polystyrene (PS), and 2) Stability measurements will be compared to a Hamaker constant model to ascertain its effectiveness in predicting stability of nanoscale bilayers. Outcomes. The proposal work will provide the first systematic measurements of VDW stability of insulator/semiconductor and insulator/conductor thin film bilayers. This exploration will set important limitations and demonstrate the feasibility of incorporating nanoscale conductor / insulator junctions in device architectures. Educational Plan and Significance. The educational goal of the PI is to increase the content, breadth, and inclusiveness of the instructional process for surface and colloid science at Georgia Tech. To meet these needs this research will supplement the PI's continuing educational thrusts: * Development of a graduate course in surface and colloid science chemical engineering * Internet-available surface lecture examples for undergraduate engineering courses * Active recruitment of the local community, minority, and underrepresented students in engineering research.