Re-entrant direct hexagonal phases in a lyotropic system of surfactant induced by an ionic liquid

Saheli Mitra, Ramesh Karri, Praveen Kumar Mylapalli, Arka Bikash Dey, Gourav Bhattacharya, Gouriprasanna Roy, Syed Mohammed Kamil, Surajit Dhara, Sunil Kumar Sinha, Sajal Kumar Ghosh

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In the present study, an ionic liquid (IL), known as green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF 4) with four carbons in the hydrophobic chain (C-4) has been used as an additive to modify the self-assembled aggregates of an anionic surfactant sodium dodecyl sulfate (SDS) and then the evolution of the liquid crystalline phases has been investigated. Small angle synchrotron x-ray diffraction study has revealed an unprecedented phase sequence where a hexagonal phase (H I) of direct cylindrical micelles is observed to evolve to another hexagonal phase (H II) of, again, direct cylindrical micelles with a lamellar phase (L α) as the intermediate. The rheological data and the theoretical calculations have confirmed the phases. To understand such a phase behaviour of the system, the work is extended by considering the ionic liquids with the same head group but of shorter (C-2) and longer (C-10) hydrocarbon chains compared to BMIM-BF4. While the shorter chain IL causes the hexagonal phase to form rectangular (R) phase, the longer chain is observed to induce the lamellar phase (L α). The molecular mechanism of appearance of such different phases has been discussed.

LanguageEnglish
Pages1327-1339
Number of pages13
JournalLiquid Crystals
Volume46
Issue number9
DOIs
Publication statusPublished - 15 Jul 2019

Keywords

  • Lyotropic liquid crystal
  • surfactant
  • ionic liquids
  • rheology
  • small angle x-ray diffraction

Cite this

Mitra, Saheli ; Karri, Ramesh ; Mylapalli, Praveen Kumar ; Dey, Arka Bikash ; Bhattacharya, Gourav ; Roy, Gouriprasanna ; Kamil, Syed Mohammed ; Dhara, Surajit ; Sinha, Sunil Kumar ; Ghosh, Sajal Kumar. / Re-entrant direct hexagonal phases in a lyotropic system of surfactant induced by an ionic liquid. In: Liquid Crystals. 2019 ; Vol. 46, No. 9. pp. 1327-1339.
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abstract = "In the present study, an ionic liquid (IL), known as green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF 4) with four carbons in the hydrophobic chain (C-4) has been used as an additive to modify the self-assembled aggregates of an anionic surfactant sodium dodecyl sulfate (SDS) and then the evolution of the liquid crystalline phases has been investigated. Small angle synchrotron x-ray diffraction study has revealed an unprecedented phase sequence where a hexagonal phase (H I) of direct cylindrical micelles is observed to evolve to another hexagonal phase (H II) of, again, direct cylindrical micelles with a lamellar phase (L α) as the intermediate. The rheological data and the theoretical calculations have confirmed the phases. To understand such a phase behaviour of the system, the work is extended by considering the ionic liquids with the same head group but of shorter (C-2) and longer (C-10) hydrocarbon chains compared to BMIM-BF4. While the shorter chain IL causes the hexagonal phase to form rectangular (R) phase, the longer chain is observed to induce the lamellar phase (L α). The molecular mechanism of appearance of such different phases has been discussed.",
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author = "Saheli Mitra and Ramesh Karri and Mylapalli, {Praveen Kumar} and Dey, {Arka Bikash} and Gourav Bhattacharya and Gouriprasanna Roy and Kamil, {Syed Mohammed} and Surajit Dhara and Sinha, {Sunil Kumar} and Ghosh, {Sajal Kumar}",
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Mitra, S, Karri, R, Mylapalli, PK, Dey, AB, Bhattacharya, G, Roy, G, Kamil, SM, Dhara, S, Sinha, SK & Ghosh, SK 2019, 'Re-entrant direct hexagonal phases in a lyotropic system of surfactant induced by an ionic liquid', Liquid Crystals, vol. 46, no. 9, pp. 1327-1339. https://doi.org/10.1080/02678292.2019.1566507

Re-entrant direct hexagonal phases in a lyotropic system of surfactant induced by an ionic liquid. / Mitra, Saheli; Karri, Ramesh; Mylapalli, Praveen Kumar; Dey, Arka Bikash; Bhattacharya, Gourav; Roy, Gouriprasanna; Kamil, Syed Mohammed; Dhara, Surajit; Sinha, Sunil Kumar; Ghosh, Sajal Kumar.

In: Liquid Crystals, Vol. 46, No. 9, 15.07.2019, p. 1327-1339.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Re-entrant direct hexagonal phases in a lyotropic system of surfactant induced by an ionic liquid

AU - Mitra, Saheli

AU - Karri, Ramesh

AU - Mylapalli, Praveen Kumar

AU - Dey, Arka Bikash

AU - Bhattacharya, Gourav

AU - Roy, Gouriprasanna

AU - Kamil, Syed Mohammed

AU - Dhara, Surajit

AU - Sinha, Sunil Kumar

AU - Ghosh, Sajal Kumar

N1 - No Accepted Version

PY - 2019/7/15

Y1 - 2019/7/15

N2 - In the present study, an ionic liquid (IL), known as green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF 4) with four carbons in the hydrophobic chain (C-4) has been used as an additive to modify the self-assembled aggregates of an anionic surfactant sodium dodecyl sulfate (SDS) and then the evolution of the liquid crystalline phases has been investigated. Small angle synchrotron x-ray diffraction study has revealed an unprecedented phase sequence where a hexagonal phase (H I) of direct cylindrical micelles is observed to evolve to another hexagonal phase (H II) of, again, direct cylindrical micelles with a lamellar phase (L α) as the intermediate. The rheological data and the theoretical calculations have confirmed the phases. To understand such a phase behaviour of the system, the work is extended by considering the ionic liquids with the same head group but of shorter (C-2) and longer (C-10) hydrocarbon chains compared to BMIM-BF4. While the shorter chain IL causes the hexagonal phase to form rectangular (R) phase, the longer chain is observed to induce the lamellar phase (L α). The molecular mechanism of appearance of such different phases has been discussed.

AB - In the present study, an ionic liquid (IL), known as green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF 4) with four carbons in the hydrophobic chain (C-4) has been used as an additive to modify the self-assembled aggregates of an anionic surfactant sodium dodecyl sulfate (SDS) and then the evolution of the liquid crystalline phases has been investigated. Small angle synchrotron x-ray diffraction study has revealed an unprecedented phase sequence where a hexagonal phase (H I) of direct cylindrical micelles is observed to evolve to another hexagonal phase (H II) of, again, direct cylindrical micelles with a lamellar phase (L α) as the intermediate. The rheological data and the theoretical calculations have confirmed the phases. To understand such a phase behaviour of the system, the work is extended by considering the ionic liquids with the same head group but of shorter (C-2) and longer (C-10) hydrocarbon chains compared to BMIM-BF4. While the shorter chain IL causes the hexagonal phase to form rectangular (R) phase, the longer chain is observed to induce the lamellar phase (L α). The molecular mechanism of appearance of such different phases has been discussed.

KW - Lyotropic liquid crystal

KW - surfactant

KW - ionic liquids

KW - rheology

KW - small angle x-ray diffraction

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U2 - 10.1080/02678292.2019.1566507

DO - 10.1080/02678292.2019.1566507

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