Mixing Enhancement Effect of Low-molecular-weight Organogelators for Thixotropic Organogel Creation

Ohsedo, Yutaka; Watanabe, Hisayuki; Oono, Masashi; Tanaka, Akihiro

doi:10.1246/cl.121203

Cited by 20 publications

(22 citation statements)

References 22 publications

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“…Because it is known that (1) small changes in gelator structure can cause large changes in gelation properties and (2) the naturally occurring alkanoic acid ( R )‐12‐hydroxystearic acid (12HSA) and its derivatives are much more efficient gelators than their structurally related stearic acid derivatives, we reasoned that replacing the stearic acid part of the stearylhydrazides examined previously with 12HSA might result in gelators ( n ‐HSAH in Scheme ) capable of forming gels with significantly different and improved characteristics. Herein we report that the addition of a hydroxyl group along the chain of the stearylhydrazides does in fact lead to important changes in the properties of the gels.…”

Section: Introductionmentioning

confidence: 62%

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(R)‐12‐Hydroxystearic Acid Hydrazides as Very Efficient Gelators: Diffusion, Partial Thixotropy, and Self‐Healing in Self‐Standing Gels

Zhang

Weiss

2016

Chemistry An Asian Journal

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The gelation properties of derivatives of N-alkylated (R)-12-hydroxystearic acid hydrazide (n-HSAH, n=0, 2, 6, 10; n is the length of an n-alkyl chain on the terminal nitrogen atom) in a wide variety of liquids is reported. The n-HSAH compounds were derived from a naturally occurring alkanoic acid, (R)-12-hydroxystearic acid (R-12HSA), and although they differ from the analogous N-alkyl (R)-12-hydroxystearamides (n-HSAA) only by the presence of one N-H group, their behavior as gelators is very different. For example, the parent molecule (0-HSAH) is a supergelator in ethylene glycol, in which it forms self-standing gels that are self-healing, partially thixotropic, moldable, and load-bearing; gels of 0-HSAA are not self-standing. 0-HSAH is structurally the simplest molecular gelator of which we are aware that is capable of forming both self-standing and partially thixotropic gels. Also, diffusion of the cationic dye erythrosine B and the anionic dye methylene blue in 0-HSAH/ethylene glycol gel blocks is much slower than the self-diffusion of ethylene glycol. Polarizing optical microscopy, X-ray diffraction, and FTIR studies revealed that the self-assembled fibrillar networks (SAFINs) of the gels are crystalline, and that 0-HSAH molecules may be arranged in a triclinic subcell with bilayer stacking. The SAFINs are stabilized by strong hydrogen-bonding interactions between the hydrazide groups of adjacent molecules and a perpendicular hydrogen-bonding network between the pendent hydroxyl groups of 0-HSAH. The other n-HSAH (n=2, 6, 10) molecules appear to be arranged in orthorhombic subcells with monolayers and strong hydrogen-bonding interactions between the hydrazide group of one gelator molecule and the hydroxyl group of a neighboring one. These results show how small structural modifications of structurally simple gelator molecules can be exploited to form gels with novel properties that can lead potentially to valuable applications, such as in drug delivery.

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Section: Introductionmentioning

confidence: 62%

“…Recently, good alkylhydrazide gelators have been made from alkanoic acids . They form organogels in liquids with dielectric constants that range from 2 to 66, and mixtures of their homologues provide gels with some thixotropic properties …”

Section: Introductionmentioning

confidence: 99%

(R)‐12‐Hydroxystearic Acid Hydrazides as Very Efficient Gelators: Diffusion, Partial Thixotropy, and Self‐Healing in Self‐Standing Gels

Zhang

Weiss

2016

Chemistry An Asian Journal

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“…Although these molecular gels have relatively weak mechanical stability, we demonstrated that the mechanical properties of the alkylhydrazide molecular gels can be enhanced by simply mixing alkylhydrazides with different alkyl chain lengths . Moreover, the critical gelation concentration of the mixtures is decreased (enhanced) compared to those for each single alkylhydrazide gelator.…”

Section: New Alkylhydrazide Organogelator and Mixed Lmwgs For Improvementioning

confidence: 85%

“…[37] Moreover, the critical gelation concentration of the mixtures is decreased (enhanced) compared to those for each single alkylhydrazide gelator. Furthermore, thixotropic behavior or mechanically induced switching of the sol-to-gel transition was observed for the mixed alkylhydrazide molecular gels while each alkylhydrazide alone did not exhibit this behavior.…”

Section: New Alkylhydrazide Organogelator and Mixed Lmwgs For Improvementioning

confidence: 98%

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Low-molecular-weight organogelators as functional materials for oil spill remediation

Ohsedo

2015

Polym. Adv. Technol.

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Oil spills from tankers are one of the major types of man-made disasters that impact the marine environment, and they have been shown to have long-lasting effects. On prevention of the spread of oil through rapid cleanup of spills, low-molecular-weight organogelators have received much attention because of their ability to tune their properties through rational design. In this mini-review, I present a brief summary of studies focused on the remediation of oil spills via a chemical method, which involves the use of low-molecular-weight organogelators that form organogels with fuel oils or organic solvents. Moreover, recent attempts to create new improved molecular organogels composed of commercially available simple organogelators via a mixing induced enhancement method for solidifying oil are also discussed. In addition, polymer organogelators for oil spills are discussed in relation to low-molecular weight gelators.

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Stearoylamido‐D‐Glucamine Hydrogelators for Thixotropic Molecular Gels with Tunable Softness by Chemical Modification

Ohsedo

2022

Chemistry An Asian Journal

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Low-molecular-weight hydrogelators containing stearoyl, glycine, and D-glucamine moieties with or without methyl groups were synthesized to prepare chemically tuned molecular hydrogels. To evaluate the role of hydrogen bonding of hydrogelators in molecular hydrogel formation, the author has newly synthesized hydrogelators with or without methyl groups at their NÀ H in amide groups, contributing to the hydrogen bond formation in fiber in molecular hydrogels. The obtained hydrogels exhibited improved thixotropic performance with tunable softness, exhibiting pseudo-reversible thixotropic cycles that depended on the methyl substitution positions in the hydrogelators. To change the hydrogen bonds' positions by chemical modification has made it possible to tune the mechanical properties of molecular gels.

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Mixing Enhancement Effect of Low-molecular-weight Organogelators for Thixotropic Organogel Creation

Cited by 20 publications

References 22 publications

(R)‐12‐Hydroxystearic Acid Hydrazides as Very Efficient Gelators: Diffusion, Partial Thixotropy, and Self‐Healing in Self‐Standing Gels

(R)‐12‐Hydroxystearic Acid Hydrazides as Very Efficient Gelators: Diffusion, Partial Thixotropy, and Self‐Healing in Self‐Standing Gels

Low-molecular-weight organogelators as functional materials for oil spill remediation

Stearoylamido‐D‐Glucamine Hydrogelators for Thixotropic Molecular Gels with Tunable Softness by Chemical Modification

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