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Abstract Understanding photoreaction dynamics in crystals is important for predicting the dynamic property changes accompanying these photoreactions. In this work, we investigate the photoreaction dynamics ofp‐phenylenediacrylic acid dimethyl ester (p‐PDAMe) in single crystals that show reaction front propagation, in which the photoreaction proceeds heterogeneously from the edge to the center of the crystal. Moreover, we find thatp‐PDAMesingle crystals exhibit a distinctive crystal shape change from a parallelogram to a distorted shape resembling a fluttering flag, then to a rectangle as the photoreaction proceeds. Density functional theory calculations predict the crystal structure after the photoreaction, providing a reasonable explanation of the distinctive crystal shape change that results from the spatially heterogeneous photoreaction. These results prove that the spatially heterogeneous photoreaction dynamics have the ability to induce novel crystal shape changes beyond what would be expected based on the equilibrium reactant and product crystal shapes.
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Harnessing irreversible thermal strain for shape memory in polymer additive manufacturing
ABSTRACT Shape transformation upon annealing of fused filament fabrication additively manufacturing structures is investigated as a one‐way shape memory strategy using commodity thermoplastics. Irreversible thermal strain, which is a measurement of shape transformation upon annealing, is shown to depend on both raster angle and layer thickness, both of which are parameters than can be easily adjusted on most FFF printers. We present an algorithm based on our understanding of the underlying micromechanics of the system that allows for input of desired final dimensions and output the necessary print parameters. We also demonstrate that this approach is extensible to other materials and report more complex shape memory geometries. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 48239.
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- Award ID(s):
- 1853480
- PAR ID:
- 10460224
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Applied Polymer Science
- Volume:
- 136
- Issue:
- 47
- ISSN:
- 0021-8995
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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