TY - JOUR
T1 - Quadruple Hydrogen Bonding Supramolecular Elastomers for Melt Extrusion Additive Manufacturing
AU - Chen, Xi
AU - Zawaski, Callie E.
AU - Spiering, Glenn A.
AU - Liu, Boer
AU - Orsino, Christina M.
AU - Moore, Robert B.
AU - Williams, Christopher B.
AU - Long, Timothy E.
N1 - Funding Information:
The authors acknowledge Prof. Feng Lin and Zhengrui Xu for expertise and instrumentation for electron microscopy. This material is based upon work supported by the National Science Foundation under Grant No. DMR-1809291. The authors thank the insightful discussion with Philip J. Scott and Emily M. Wilts and the support from the Department of Chemistry, Macromolecules Innovation Institute (MII), and Nanoscale Characterization and Fabrication Laboratory (NCFL) at Virginia Tech.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/7/15
Y1 - 2020/7/15
N2 - This manuscript describes the versatility of highly directional, noncovalent interactions, i.e., quadruple hydrogen bonding (QHB), to afford novel polyurea segmented supramolecular polymers for melt extrusion three-dimensional (3D) printing processes. The molecular design of the polyurea elastomers features (1) flexible polyether segments and relatively weak urea hydrogen-bonding sites in the soft segments to provide elasticity and toughness, and (2) strong ureido-cytosine (UCyt) QHB in the hard segments to impart enhanced mechanical integrity. The resulting polyureas were readily compression-molded into mechanically-robust, transparent, and creasable films. Optimization of polyurea composition offered a rare combination of high tensile strength (95 MPa), tensile elongation (788% strain), and toughness (94 MJ/m3), which are superior to a commercially available Ninjaflex elastomer. The incorporation of QHB facilitated melt processability, where hydrogen bonding dissociation provided low viscosities at printing temperatures. During cooling, directional self-assembly of UCyt QHB facilitated the solidification process and contributed to part fidelity with the formation of a robust physical network. The printed objects displayed high layer fidelity, smooth surfaces, minimal warpage, and complex geometries. The presence of highly directional QHB effectively diminished mechanical anisotropy, and the printed samples exhibited comparable Young's moduli along (x-y direction, 0°) and perpendicular to (z-direction, 90°) the layer direction. Remarkably, the printed samples exhibited ultimate tensile strains approaching 500% in the z-direction prior to failure, which was indicative of improved interlayer adhesion. Thus, this design paradigm, which is demonstrated for novel polyurea copolymers, suggests the potential of supramolecular polymers with enhanced mechanical performance, melt processability, recyclability, and improved interlayer adhesion for melt extrusion additive manufacturing processes.
AB - This manuscript describes the versatility of highly directional, noncovalent interactions, i.e., quadruple hydrogen bonding (QHB), to afford novel polyurea segmented supramolecular polymers for melt extrusion three-dimensional (3D) printing processes. The molecular design of the polyurea elastomers features (1) flexible polyether segments and relatively weak urea hydrogen-bonding sites in the soft segments to provide elasticity and toughness, and (2) strong ureido-cytosine (UCyt) QHB in the hard segments to impart enhanced mechanical integrity. The resulting polyureas were readily compression-molded into mechanically-robust, transparent, and creasable films. Optimization of polyurea composition offered a rare combination of high tensile strength (95 MPa), tensile elongation (788% strain), and toughness (94 MJ/m3), which are superior to a commercially available Ninjaflex elastomer. The incorporation of QHB facilitated melt processability, where hydrogen bonding dissociation provided low viscosities at printing temperatures. During cooling, directional self-assembly of UCyt QHB facilitated the solidification process and contributed to part fidelity with the formation of a robust physical network. The printed objects displayed high layer fidelity, smooth surfaces, minimal warpage, and complex geometries. The presence of highly directional QHB effectively diminished mechanical anisotropy, and the printed samples exhibited comparable Young's moduli along (x-y direction, 0°) and perpendicular to (z-direction, 90°) the layer direction. Remarkably, the printed samples exhibited ultimate tensile strains approaching 500% in the z-direction prior to failure, which was indicative of improved interlayer adhesion. Thus, this design paradigm, which is demonstrated for novel polyurea copolymers, suggests the potential of supramolecular polymers with enhanced mechanical performance, melt processability, recyclability, and improved interlayer adhesion for melt extrusion additive manufacturing processes.
KW - extrusion additive manufacturing
KW - mechanical property
KW - microphase separation
KW - quadruple hydrogen bonding
KW - rheology
KW - supramolecular polymer
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U2 - 10.1021/acsami.0c08958
DO - 10.1021/acsami.0c08958
M3 - Article
C2 - 32520520
AN - SCOPUS:85088270059
SN - 1944-8244
VL - 12
SP - 32006
EP - 32016
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 28
ER -