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Title
Japanese: 
English:Terminal Functionalization with a Triptycene Motif that Dramatically Changes the Structural and Physical Properties of an Amorphous Polymer 
Author
Japanese: 石割 文崇, 岡部 玄, 荻原 響, 梶谷 孝, M. Tokita, M. Takata, 福島 孝典.  
English: F. Ishiwari, G. Okabe, H. Ogiwara, T. Kajitani, M. Tokita, M. Takata, T. Fukushima.  
Language English 
Journal/Book name
Japanese: 
English:Journal of the American Chemical Society 
Volume, Number, Page Vol. 140    Issue 41    Page 13497–13502
Published date Oct. 3, 2018 
Publisher
Japanese: 
English: 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
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Official URL https://pubs.acs.org/doi/10.1021/jacs.8b09242
 
DOI https://doi.org/10.1021/jacs.8b09242
Abstract A surprising terminal-group effect on the structural and physical properties of an amorphous polymer is reported. We recently demonstrated that triptycene derivatives with substituents at the 1,8,13-positions show specific self-assembly behavior, enabling the formation of a well-defined “2D + 1D” structure based on nested hexagonal packing of the triptycenes. Upon terminal functionalization with a 1,8-substituted triptycene (1,8-Trip), a liquid polymer, polydimethylsiloxane (PDMS, Mn = 18–24 kDa), turned into a highly viscous solid that exhibits birefringence at 25 °C. Small-angle and wide-angle X-ray scattering measurements revealed that the resulting telechelic PDMS assembles into a 2D + 1D structure, where layers of PDMS domains, formed between 2D assemblies of the triptycene termini, stack into a 1D multilayer structure with a layer spacing of 18–20 nm. Because of this structuring, the complex viscosity of the telechelic PDMS was dramatically enhanced, providing a value 4 orders of magnitude greater than that of the original PDMS. Remarkably, the structural and physical properties of PDMS were hardly changed upon terminal functionalization with another regioisomer of triptycene (1,4-Trip), which differs only in the substitution pattern.

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