2020 Fiscal Year Annual Research Report
三脚型トリプチセン機能団が誘起する特異な高分子自己集合化と機能発現
| Project/Area Number |
20J23317
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
CHEN YUGEN 東京工業大学, 物質理工学院, 特別研究員(DC1)
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| Project Period (FY) |
2020-04-24 – 2023-03-31
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| Keywords | Tripodal Triptycene / Self-assembly / Telechelic Polymer / Polydimethylsiloxane / Narrow-disperse / Polyethylene Glycol |
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| Outline of Annual Research Achievements |
In 2020, I conducted three aspects of research as described in the application.
First, I have investigated the properties of 1,8,13-disubstituted triptycene terminal functionalized PDMS (1,8,13-TripPDMS). Unlike conventional PDMS polymers, a free-standing film of 1,8,13-TripPDMS could be fabricated without any chemical crosslinking. To the best of my knowledge, this is the first example of terminal functionalized PDMS elastomer with periodic order. I believe that this work will lead to the development of thermoplastic PDMS materials.
Second, to reach a deeper understanding of the role of the tripodal triptycene termini in enhancing the physical properties of PDMS, I designed and synthesized narrow-1,8-TripPDMS. I noticed that narrow-1,8-TripPDMS displayed low self-assembling properties but exhibited largely enhanced self-assembling and mechanical properties upon adding a small amount of tripodal triptycene. This finding supports a simple method for controlling the mechanical properties of tripodal triptycene modified materials.
Third, for the development of stimuli-responsive polymers with triptycene units, I designed and synthesized tripodal triptycene functionalized telechelic polyethylene glycol (PEG) (1,8-TripPEG) and telechelic PEG with 1,4-disubstituted triptycene termini. I confirmed that both 1,8-TripPEG and 1,4-TripPEG exhibited LCST behaviors in an aqueous solution. Remarkably, the LCST of 1,8-TripPEG (52 °C) was much lower than that of 1,4-TripPEG (71 °C), presumably due to the difference in the self-assembly behavior of the terminal triptycene units.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
First, I synthesized telechelic PDMS (1,8,13-TripPDMS) with three different functional groups at the 1, 8, and 13 positions of triptycene termini. I found that 1,8,13-TripPDMS shows a million times higher complex viscosity value than conventional PDMS and can form a free-standing film without chemical crosslinking. Since 1,8,13-TripPDMS film can be reproduced, both reversibility and recyclability of film are confirmed by tensile measurement, in which the recycled film exhibited the same mechanical properties.
Second, I also synthesized and characterized tripodal triptycene terminated PDMS with narrow molecular weight dispersity (narrow-1,8-TripPDMS). Narrow-1,8-TripPDMS exhibited lower self-assembling property properties than wide-distribution 1,8-TripPDMS due to the lack of lower molecular weight telechelic PDMS. Since the given fact that narrow-1,8-TripPDMS exhibited enhanced self-assembling and mechanical properties upon the addition of a small amount of tripodal triptycene, giving rise to a self-standing film.
Third, I have conducted the synthesis and characterization of triptycene terminal telechelic polyethylene glycol (TripPEG). The telechelic PEG with 1,8-disubstituted triptycene termini (1,8-TripPEG) and a control telechelic PEG with 1,4-disubstituted triptycene termini (1,4-TripPEG) were synthesized. These TriPEGs displayed different LCST behaviors and gelation properties in aqueous media due to the difference in the self-assembly behavior of the terminal triptycene units.
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| Strategy for Future Research Activity |
In 2021, I plan to continue investigating the properties of TripPEG in more detail. Since TripPEG exhibits LCST behaviour upon changing the temperature in both solution and gel states, I will explore the actuation properties of the aqueous TripPEG gel. Besides, PEG is a biocompatible polymer, and thus, I will evaluate the properties of TripPEG gel for biological applications. Furthermore, the other stimuli-responsive water-soluble polymers (i.e., PNIPAAM) with triptycene units will be synthesized. The self-assembly properties of these water-soluble telechelic polymers in bulk and aqueous media will be evaluated by DSC, TGA, XRD and microscopy analyses, along with light scattering measurements. Additionally, I will conduct computational calculations to study the dynamics and structures of these telechelic polymers.
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