| 研究実績の概要 |
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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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
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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| 今後の研究の推進方策 |
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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