Mechanisms of Elasticity in Semiconducting Polymers
Abstract
Semiconducting (pi conjugated) polymers have the potential to combine the electronic properties of inorganic semiconductors with the mechanical properties of plastic. Favorable charge transport properties and mechanical deformability are, however, in competition. For example, the rigid ? conjugated backbone and semicrystalline microstructure are necessary for charge transport but also tend to reduce the deformability. Despite these seemingly exclusive criteria, our laboratory and others have demonstrated materials that can be stretched by over 100% while retaining high charge carrier mobility. There are two challenges obscured by this progress. The first challenge is that the deformation is generally plastic, as opposed to elastic. The elastic range is by far the more important than the absolute “stretchability,” because a material that can only be stretched once before it deforms permanently will not be usable in most applications. The elastic range of most “stretchable” semiconducting polymers is small, ?10%. The second challenge is that most previous approaches to increasing the deformability of conjugated polymers have been based on intuition, e.g., increasing the length of the side chain and incorporating aliphatic spacers. These approaches are based on the assumption that the flexibility of the polymer chain directly translates into the deformability of the film. Our results contradict this assumption. The molecular structure influences the mechanical properties of the solid in large part insofar as it influences the solid state structure. The goals of this proposal are thus (1) to understand the mechanisms of elasticity at the molecular and microstructural level and (2) to increase the elastic range. Stretchable, ultra flexible, printable, and robust semiconducting polymers can provide energy for aerospace and satellite applications and can transduce signals for human and structural health monitoring.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910278
Entities
People
- Darren J. Lipomi
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of California, San Diego