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Amino Acid Based Low-Molecular-Weight Ionogels as Efficient Dye-Adsorbing Agents and Templates for the Synthesis of TiO2 Nanoparticles

Authors

  • Sounak Dutta,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India), Fax: (+91) 33-24732805
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  • Dibyendu Das,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India), Fax: (+91) 33-24732805
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  • Antara Dasgupta,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India), Fax: (+91) 33-24732805
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  • Prasanta Kumar Das Dr.

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India), Fax: (+91) 33-24732805
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Abstract

The gelation of ionic liquids is attracting significant attention because of its large spectrum of applications across different disciplines. These ‘green solvents’ have been the solution to a number of common problems due to their eco-friendly features. To expand their applications, the gelation of ionic liquids has been achieved by using amino acid-based low-molecular-weight compounds. Variation of individual segments in the molecular skeleton of the gelators, which comprise the amino acid and the protecting groups at the N and C termini, led to an understanding of the structure–property correlation of the ionogelation process. An aromatic ring containing amino acid-based molecules protected with a phenyl or cyclohexyl group at the N terminus were efficient in the gelation of ionic liquids. In the case of aliphatic amino acids, gelation was more prominent with a phenyl group as the N-terminal protecting agent. The probable factors responsible for this supramolecular association of the gelators in ionic liquids have been studied with the help of field-emission SEM, 1H NMR, FTIR, and luminescence studies. It is the hydrophilic–lipophilic balance that needs to be optimized for a molecule to induce gelation of the green solvents. Interestingly, to maximize the benefits from using these green solvents, these ionogels have been employed as templates for the synthesis of uniform-sized TiO2 nanoparticles (25–30 nm). Furthermore, as a complement to their applications, ionogels serve as efficient adsorbents of both cationic and anionic dyes and were distinctly better relative to their organogel counterparts.

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