Anomalous spreading behaviour of polyethyleneglycoldistearate monolayers at air/water interface

Journal of Chemical Sciences

S John Collins¹  Aruna Dhathathreyan1¹  T Ramasami¹ 

[1] Chemical Lab., Central Leather Research Institute, Adyar, Chennai 600 020, India$$

关键词: Anomalous behaviour;    polythyleneglycoldistearate;    air/water interface;    surface pressure-area isotherms;    condensed microcrystallites.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

Spreading behaviour of the dimeric surfactant polyethyleneglycoldistearate (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 both 𝐴-𝑇 and 𝜋-𝑇 at constant area show transitions at 𝑇 = 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.

【 授权许可】

Unknown