| Autor: |
Miller KA; Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States., Alemany LB; Department of Chemistry and Shared Equipment Authority, Rice University, Houston, Texas 77005, United States., Roy S; Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States., Yan Q; Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States., Demingos PG; Department wof Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada., Singh CV; Department wof Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada., Alahakoon S; Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States., Egap E; Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States., Thomas EL; Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States., Ajayan PM; Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States. |
| Abstrakt: |
Two-dimensional (2D) rigid polymers provide an opportunity to translate the high-strength, high-modulus mechanical performance of classic rigid-rod 1D polymers across a plane by extending covalent bonding into two dimensions while simultaneously reducing density due to microporosity by structural design. Thus far, this potential has remained elusive because of the challenge of producing high-quality 2D polymer thin films, particularly those with irreversible, rigid benzazole linkages. Here, we present a facile two-step process that allows the deposition of a uniform intermediate film network via reversible, non-covalent interactions, followed by a subsequent solid-state annealing step that facilitates the irreversible conversion to a 2D covalently bonded polymer product with benzoxazole linkages. We demonstrate the versatility of this synthesis method by producing films with four different aromatic core units. The resulting films show microporosity and anisotropy with a 2D layered structure that can be exfoliated into few-layer nanosheets using a freeze-thaw method. These films have promising mechanical properties with an in-plane ultimate tensile strength of nearly 40 MPa and axial tensile and transverse compressive elastic moduli on the scale of several GPa, rivaling the performance of solution-cast films of 1D polybenzoxazole, as well as several other 1D high-strength polymer films. |
