Gelation of graphene oxides induced by different types of amino acids

Heeyoung Ahn, Taehoon Kim, Hoon Choi, Cheolsang Yoon, Kiju Um, Jaewook Nam, Kyung Hyun Ahn, Kangtaek Lee

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We have investigated gelation of graphene oxide (GO) sheets induced by amino acids. For gelation of single layer GO sheets, six different types of amino acids were added to GO suspension as gelators. To understand gelation mechanism, we varied the concentration and type of amino acids as well as the pH of suspension, and monitored the morphology and rheological properties of reaction mixtures. Gelation was observed in acidic pH only with three types of amino acids (arginine, tryptophan, and cysteine) whereas no gel was formed at other pH values (neutral and basic). As the type of amino acid was varied, both the binding strength between amino acid and GO and the moduli (G′ and G′′) of reaction mixtures followed the same order, arginine > cysteine > tryptophan > asparagine > aspartic acid > glycine. To rationalize these results, we considered interactions between amino acid side chains and GO sheets (i.e., electrostatic interaction, π-π stacking, and hydrogen bonding), and found that the hydrogel formed by electrostatic attraction with arginine exhibited shorter gel time and larger moduli than the other samples. Finally, synthesis of GO hydrogel at physiological pH was demonstrated by increasing the concentration of GO sheets.

Original languageEnglish
Pages (from-to)229-237
Number of pages9
JournalCarbon
Volume71
DOIs
Publication statusPublished - 2014 May 1

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Graphite
Gelation
Oxides
Graphene
Amino acids
Amino Acids
Arginine
Hydrogel
Tryptophan
Cysteine
Hydrogels
Suspensions
Gels
Asparagine
Coulomb interactions
Aspartic Acid
Glycine
Electrostatics
Hydrogen bonds
Acids

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)

Cite this

Ahn, Heeyoung ; Kim, Taehoon ; Choi, Hoon ; Yoon, Cheolsang ; Um, Kiju ; Nam, Jaewook ; Ahn, Kyung Hyun ; Lee, Kangtaek. / Gelation of graphene oxides induced by different types of amino acids. In: Carbon. 2014 ; Vol. 71. pp. 229-237.
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abstract = "We have investigated gelation of graphene oxide (GO) sheets induced by amino acids. For gelation of single layer GO sheets, six different types of amino acids were added to GO suspension as gelators. To understand gelation mechanism, we varied the concentration and type of amino acids as well as the pH of suspension, and monitored the morphology and rheological properties of reaction mixtures. Gelation was observed in acidic pH only with three types of amino acids (arginine, tryptophan, and cysteine) whereas no gel was formed at other pH values (neutral and basic). As the type of amino acid was varied, both the binding strength between amino acid and GO and the moduli (G′ and G′′) of reaction mixtures followed the same order, arginine > cysteine > tryptophan > asparagine > aspartic acid > glycine. To rationalize these results, we considered interactions between amino acid side chains and GO sheets (i.e., electrostatic interaction, π-π stacking, and hydrogen bonding), and found that the hydrogel formed by electrostatic attraction with arginine exhibited shorter gel time and larger moduli than the other samples. Finally, synthesis of GO hydrogel at physiological pH was demonstrated by increasing the concentration of GO sheets.",
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Ahn, H, Kim, T, Choi, H, Yoon, C, Um, K, Nam, J, Ahn, KH & Lee, K 2014, 'Gelation of graphene oxides induced by different types of amino acids', Carbon, vol. 71, pp. 229-237. https://doi.org/10.1016/j.carbon.2014.01.033

Gelation of graphene oxides induced by different types of amino acids. / Ahn, Heeyoung; Kim, Taehoon; Choi, Hoon; Yoon, Cheolsang; Um, Kiju; Nam, Jaewook; Ahn, Kyung Hyun; Lee, Kangtaek.

In: Carbon, Vol. 71, 01.05.2014, p. 229-237.

Research output: Contribution to journalArticle

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