Design, Synthesis, and Characterization of Phase Change Materials Based on Nanoparticle-doped Block Ionene Polymers
Abstract
Phase change materials present exciting opportunities to enhance performance characteristics in response to an externally applied stimulus. Despite significant progress in recent years, there remain gaps in our understanding of and ability to control material microstructure to develop phase change materials with continuous conductive pathways. We propose a coordinated synthesis, modeling, and fabrication research effort to enable the rational design of multifunctional polymer-based phase change materials. Specifically, electrically conductive nanoparticles will be integrated into a segmented ionene polymer with a controllable amount of ionic groups versus semicrystalline spacers with low glass transition temperature. The type and amount of ionic segments dictate the polymer microstructure and the low Tg spacer between ionic microphase separated domains enables strain-induced crystallization. This hierarchy suggests that a modest applied strain could induce crystallization, which could adjust the microphase structure and the location of the nanoparticles significantly. Furthermore, we speculate that synergistic effect of ionic domains and crystallites will direct the nanoparticles to form a connected pathway within the composite. Thus, a metallic nanoparticle-doped semicrystalline polymer matrix could transform from an insulating amorphous structure to an electrica11y conductive crystalline structure, and the amorphous structure could be recovered after annealing. To successfully address this ambitious goal, we propose a set of objectives to test the following hypothesis: NP-functionalized, segmented ionenes whose low Tg component undergoes strain-induced crystallization can exhibit strong mechanoresponsive behavior (depending on NP and ionic segment content); in particular, NP alignment in response to strain can induce a significant change in electrical conductivity." The proposed paradigm incorporates several innovative features, including: the incorporation of phase changing segmented ionene materials into conducting nanocomposites; the reorientation ofnanofi11ers through the application of an external stimulus (strain); and a scalable and inexpensive approach for synthesis of high performance functional materials and composites. Furthermore, it will enhance our scientific understanding of the mechanoresponsive behavior of segmented ionene-nanoparticle conjugates, and the effect of molecular architecture on the microstructure and resulting strain response, such that we can harness the mechanoresponsive potential of these materials by tuning the polymer and nanoparticle structure for a variety of applications. Moreover, the proposed work potentially enables the design of melt and/or solution processable nanocomposites with predicted, tailored, and reproducible microstructures and performance; which would be a significant contribution to the processing of functional nanocomposites. From a scientific perspective, our research findings can impact the community in a transformative way. Our proposed design and methodology can be potentially expanded to facile design, processing and manufacturing of reversible mechanica1ly, electrically, optically, and/or thermally responsive nanocomposites depending on the constituent nanoparticles and polymers. The proposed research is aligned with the long-term mission of the Army to maintain its advantage in science and technology of smart and functional materials and structures; the results will provide a cornerstone for understanding, designing, and synthesizing smart adaptive materials to be used in armors for the warfighters, lightweight and stronger composite materials for Army equipment and vehicles, and other critical needs of the armed forces.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810412
Entities
People
- Reza Montazami
Organizations
- Army Contracting Command
- Iowa State University
- United States Army