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    • Keywords


      Anomalous behaviour; polythyleneglycoldistearate; air/water interface; surface pressure-area isotherms; condensed microcrystallites

    • Abstract


      Spreading behaviour of the dimeric surfactant polyethylene-glycoldistearate (PEGDS) monolayer at air/water interface has been studied using surface pressure-area (π-A) isotherms as a function of temperature. The isotherms show a plateau suggesting a transition between a liquid expanded (LE) and a condensed state. The condensed state possibly arises due to nucleation and growth of multilayers from the monolayer. Isobaric measurements of bothA-T and π-T at constant area show transitions atT = 295 K. These plots suggest a melting followed by formation of condensed microcrystallites. Structure optimization carried out using various angles of orientation of the alkyl tails with respect to the backbone in PEGDS reveals tilt transitions of the tails in different states which can be related to the packing behaviour seen in the isotherms. Optical microscopy has been used to confirm the structures in these states.

    • Author Affiliations


      S John Collins1 Aruna Dhathathreyan1 T Ramasami1

      1. Chemical Lab., Central Leather Research Institute, Adyar, Chennai - 600 020, India
    • Dates

  • Journal of Chemical Sciences | News

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