Snail shell-shaped chiral substituted helical polyacetylene: preparation, characterization and infrared emissivity performance
- 11 Downloads
The first snail shell-shaped helical polyacetylenes (SHPAs) were synthesized from the copolymerization between l-serine-grafted propargylamine (LSA) and propargylamine (PA). The novel structure was obtained at the monomer input proportion of 50%. The monomer (LSA) and copolymers (poly(LSAm-co-PAn)) were characterized by 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, circular dichroism and transmission electron microscopy. The infrared emissivity of poly(LSA50-co-PA50) investigated at 8–14 μm was 0.451, which was much lower than the other copolymers. This was because the poly(LSA50-co-PA50) could form the obvious intramolecular interaction and self-assembled to a snail-shell shape by intermolecular hydrogen bonding in MeOH solution. Meanwhile, the conjugation performance of the main chain was enhanced. Consequently, the abundant hydrogen bonds formed through N–H and C=O bonding and the strong conjugate properties both could decrease the unsaturation degree, as well as change the heat conduction mode in the molecules, thereby reducing the infrared emissivity. This strategy provided a new direction to achieve the controllable infrared stealth.
This work was funded by National Nature Science Foundation of China (51673040, 21878047), Natural Science Foundation of Jiangsu Province (BK20171357, BK20180366), Fundamental Research Funds for Central Universities (2242018k30008), Scientific Innovation Research Foundation of College Graduate in Jiangsu Province (KYCX19_0103), Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (1107047002), and Fund Project for Transformation of Scientific and Technological Achievements of Jiangsu, Province of China (BA2018045).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 30.Percec V, Obata M, Rudick JG, De BB, Glodde M, Bera TK, Magonov SN, Balagurusamy VSK, Heiney PA (2002) Synthesis, structural analysis, and visualization of poly(2-ethynyl-9-substituted carbazole)s and poly(3-ethynyl-9-substituted carbazole)s containing chiral and achiral minidendritic substituents. J Polym Sci Part A Polym Chem 40(20):3509–3533CrossRefGoogle Scholar
- 31.Cheuk KKL, Lam JWY, Lai LM, Dong YP, Tang BZ (2003) Syntheses, hydrogen-bonding interactions, tunable chain helicities, and cooperative supramolecular associations and dissociations of poly(phenylacetylene)s bearing l-valine pendants: toward the development of proteomimetic polyenes. Macromolecules 36(26):9752–9762CrossRefGoogle Scholar