Engineering Stable Glass Films Using Molecular Design and Surface-Mediated Equilibration
Nanoscopic thin films of small molecule amorphous organic materials are widely used in applications that range from protective coatings to organic photovoltaics and resist materials in nanoimprint lithography. These films are frequently manufactured through the use of physical vapor deposition (PVD) onto a substrate held below the materials' glass transition temperature, Tg. Tg signifies the temperature where a system is unable to equilibrate on laboratory or computational time scales. Since glassy systems are out of equilibrium, the precise method of their fabrication, including substrate temperature, its properties, and rate of deposition can profoundly affect the materials properties and function in these applications. This project employs a combination of molecular synthesis, high-throughput characterization, and molecular simulation to design and characterize a library of synthetic glass-forming materials as a function of deposition variables. Addressing fundamental questions of the formation of highly stable glasses during PVD will have a transformative effect on the community's ability to engineer the properties of amorphous organic thin films and open the door to new applications of stable glasses for various industries. In addition to the project's impact on our fundamental understanding of stable glass formation and industrial applications, this project will impact the education of junior scientists from the undergraduate level through the PhD level. Undergraduate education is integrated into all aspects of the project. The starting material for the synthesis of glass formers is prepared as part of an undergraduate organic chemistry laboratory course. Advanced undergraduates and graduate students participate in the synthesis of the glass-formers as well as the characterization of PVD films using various experimental and computational techniques.