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Research paper : Novel functional gels and their commercial distribution as chemical reagents (M. Yoshida)−185−Synthesiology - English edition Vol.5 No.3 (2012) gelator.” For the gelation of, for example, ionic liquids, it has been shown that the ion conductivity decreases only a few percent after gelation and is maintained.[4]-[6] In conventional ionic liquids with low viscosity, there was a trade-off where the conductivity increased as the ion mobility increased in the less viscous ionic liquids but it became likely to leak in sealed conditions due to the low viscosity. On the other hand, the highly viscous ionic liquids did not leak readily but had decreased conductivity as the ion mobility decreased due to the high viscosity. For this issue, we realized a new technology using this gelator that allowed the adjustment of viscosity only while retaining ion conductivity. Therefore, it can be used in electrochemical devices (dye sensitized solar cells, capacitors, etc.) that use ionic liquids as the electrolyte solution, and application in the coating process, increased lifespan of the operation time by preventing leakage, and other improvements in performance can be expected.4.3.3 Self-healing gelIn general, because gels have soft forms, their structures are easily destroyed by mechanical stress. Relating to the response under the mechanical stress, some gels show the “thixotropic property (thixotropy).” This is a property where the viscosity changes in response to applied stress, the substance changes into fluid sol under high stress conditions, and then returns to gel when the stress is removed. Generally, a long time is needed to return from sol to gel, and the only exception reported was the quick structural recovery of hydrogel composed of block copolymer that possesses cation charge on the side chain.[8] The authors looked at the structural similarity between the case studies and the electrolyte gelator, and investigated whether a similar characteristic could be observed. As expected, it was found that the new material had an interesting self-healing property where the storage elasticity modulus, which indicates the solidity of gel, recovered at extremely high speed (in a few seconds) after the destruction of the gel structure.[4][7][9] This structural recovery occurred at higher speed as the concentration increased. As a side story, the author at the time had no experience in the rheological measurement of gel elasticity, and we asked a measurement device manufacturer to measure the sample. It left a strong impression when the engineer who had experience in measuring numerous samples looked at the measurement of our sample and said, “I think this is a very rare phenomenon.” From the crystal structure analysis of the model compound (unpublished data), we believe this phenomenon occurs by the recovery of gel network by long-distance electrostatic interaction that arises from the fact that the electrolyte gelator is charged, rather than a short-distance interaction like the hydrogen bond. Since the once broken gel structure recovers instantly, this gel can be considered as a type of “indestructible gel,” and applications in various fields can be expected such as the impact absorbing material that utilizes high-speed structural recovery property. The author’s report was the precursor of the above high-speed self-healing gel, and many examples followed. In the functional gel “Aqua Material” that was jointly studied by Professor Takuzo Aida, Specially Appointed Assistant Professor Justin Lee Mynar (currently of King Abdullah University of Science and Technology, Saudi Arabia) of the University of Tokyo, and the authors, the formation of a water gel was observed by the interaction of clay derived nanoparticle and dendrimer that each possessed complementary charges. Since the high strength and self-healing properties were observed in this gel, the importance was again indicated of the electrostatic interaction that drives the gelation and allows self-healing.[10]4.3.4 Complexation with carbon nanotubes (CNTs)The electrolyte gelator is found to be a specific “dispersant” to CNTs, which is gaining attention as the next-generation material in the field of nanotechnology, as well as having the gelation function described before.[4] This result was found by inference from the previous example[11] of a similar polymer electrolyte for which only one report was known. In this case also, the authors had no experience in CNT research at that time. However, there were researchers involved in CNT Fig. 4 Photograph of hydrogel in inverted sample bottle (concentration at 1 wt%)Left: Pure water gel; Right: Gel containing single walled carbon nanotubes (From Reference [5])Fig. 5 Ionic liquid (EMIm-PF6) gel in an inverted sample bottle {from Reference [4] (Supporting Information) (permitted by ACS)}40 g/L30 g/L20 g/L

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