Mechanisms of Local Stress Sensing in Multifunctional Polymer Films Using Fluorescent Tetrapod Nanocrystals
| Autor: | Shilpa N. Raja, Danylo Zherebetskyy, Siva Wu, Peter Ercius, Alexander Powers, Andrew C. K. Olson, Daniel X. Du, Liwei Lin, Sanjay Govindjee, Lin-Wang Wang, Ting Xu, A. Paul Alivisatos, Robert O. Ritchie |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Photoluminescence polymer Bioengineering Nanotechnology 02 engineering and technology 010402 general chemistry 01 natural sciences Stress (mechanics) tetrapod nanocrystal sensor Ultimate tensile strength General Materials Science mechanical Nanoscience & Nanotechnology Nanoscopic scale chemistry.chemical_classification Nanocomposite Mechanical Engineering General Chemistry Polymer fluorescence spectroscopy 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Compressive strength chemistry Quantum dot 0210 nano-technology |
| Zdroj: | Nano letters, vol 16, iss 8 Raja, SN; Zherebetskyy, D; Wu, S; Ercius, P; Powers, A; Olson, ACK; et al.(2016). Mechanisms of Local Stress Sensing in Multifunctional Polymer Films Using Fluorescent Tetrapod Nanocrystals. Nano Letters, 16(8), 5060-5067. doi: 10.1021/acs.nanolett.6b01907. UC Berkeley: Retrieved from: http://www.escholarship.org/uc/item/07d5n8zk |
| Popis: | © 2016 American Chemical Society. Nanoscale stress-sensing can be used across fields ranging from detection of incipient cracks in structural mechanics to monitoring forces in biological tissues. We demonstrate how tetrapod quantum dots (tQDs) embedded in block copolymers act as sensors of tensile/compressive stress. Remarkably, tQDs can detect their own composite dispersion and mechanical properties with a switch in optomechanical response when tQDs are in direct contact. Using experimental characterizations, atomistic simulations and finite-element analyses, we show that under tensile stress, densely packed tQDs exhibit a photoluminescence peak shifted to higher energies ("blue-shift") due to volumetric compressive stress in their core; loosely packed tQDs exhibit a peak shifted to lower energies ("red-shift") from tensile stress in the core. The stress shifts result from the tQD's unique branched morphology in which the CdS arms act as antennas that amplify the stress in the CdSe core. Our nanocomposites exhibit excellent cyclability and scalability with no degraded properties of the host polymer. Colloidal tQDs allow sensing in many materials to potentially enable autoresponsive, smart structural nanocomposites that self-predict impending fracture. |
| Databáze: | OpenAIRE |
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