TY - JOUR
T1 - Quadruple hydrogen bonding containing supramolecular thermoplastic elastomers
T2 - Mechanical and morphological correlations
AU - Chen, Xi
AU - Zhang, Keren
AU - Talley, Samantha J.
AU - Orsino, Christina M.
AU - Moore, Robert B.
AU - Long, Timothy E.
N1 - Funding Information:
The authors would like to thank the support from Department of Chemistry and Institute for Critical Technology and Applied Science (ICTAS) at Virginia Tech. The authors would also like to thank insightful discussion with Kevin J. Drummey and proof reading by Chixia Tian, Ryan J. Mondschein, and Emily M. Wilts.
Publisher Copyright:
© 2018 Wiley Periodicals, Inc.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - We report the design of bioinspired, reversible supramolecular thermoplastic elastomers (TPEs) functionalized with ureido-cytosine (UCyt) complementary quadruple hydrogen bonding (QHB) sites. The polymer contained a soft poly(n-butyl acrylate) central block that imparted flexibility and two external, hard nucleobase-containing blocks that contributed to structural integrity. In addition, the hard block with pendant QHB motifs served as efficient physical crosslinks to further enhance the thermomechanical performance, where the polymer service window extended up to 30 °C higher compared to the controls that bear dimeric hydrogen bonding units. The resulting UCyt copolymers also exhibited improved surface and bulk morphology, which self-assembled into well-ordered lamellar microstructures. Moreover, the polymer displayed an unexpected moisture-resistant property with less than 1 wt % equilibrium moisture uptake even at 95% relatively humidity, which presumably correlated with its well-ordered and densely-packed morphology facilitated by strong hydrogen bonding. Variable temperature Fourier-transform infrared spectroscopy experiments further confirmed the thermoreversibility of hydrogen bonding, indicating melt-processablility and recyclability of the polymer. These physical properties verified quadruple bonding dominated behavior, and structure–property–morphology relationships suggest key design parameters for future TPEs.
AB - We report the design of bioinspired, reversible supramolecular thermoplastic elastomers (TPEs) functionalized with ureido-cytosine (UCyt) complementary quadruple hydrogen bonding (QHB) sites. The polymer contained a soft poly(n-butyl acrylate) central block that imparted flexibility and two external, hard nucleobase-containing blocks that contributed to structural integrity. In addition, the hard block with pendant QHB motifs served as efficient physical crosslinks to further enhance the thermomechanical performance, where the polymer service window extended up to 30 °C higher compared to the controls that bear dimeric hydrogen bonding units. The resulting UCyt copolymers also exhibited improved surface and bulk morphology, which self-assembled into well-ordered lamellar microstructures. Moreover, the polymer displayed an unexpected moisture-resistant property with less than 1 wt % equilibrium moisture uptake even at 95% relatively humidity, which presumably correlated with its well-ordered and densely-packed morphology facilitated by strong hydrogen bonding. Variable temperature Fourier-transform infrared spectroscopy experiments further confirmed the thermoreversibility of hydrogen bonding, indicating melt-processablility and recyclability of the polymer. These physical properties verified quadruple bonding dominated behavior, and structure–property–morphology relationships suggest key design parameters for future TPEs.
KW - block copolymers
KW - quadruple hydrogen bonding
KW - structure–property–morphology relationships
KW - supramolecular polymers
KW - ureido-cytosine
UR - http://www.scopus.com/inward/record.url?scp=85056431918&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85056431918&partnerID=8YFLogxK
U2 - 10.1002/pola.29272
DO - 10.1002/pola.29272
M3 - Article
AN - SCOPUS:85056431918
SN - 0887-624X
VL - 57
SP - 13
EP - 23
JO - Journal of Polymer Science, Part A: Polymer Chemistry
JF - Journal of Polymer Science, Part A: Polymer Chemistry
IS - 1
ER -