In this article, solvation dynamics and rotational relaxation approaches have been applied to explore the microheterogeneity of surface active ionic liquid (SAIL) containing microemulsions, i.e., [P13][Tf2N]/[BHD][AOT]/[IPM] and [N3111][Tf2N]/[BHD][AOT]/[IPM], using coumarin 480 (C-480) as a probe molecule. The average solvation time constants of Coumarin-480 (C-480) decreases with an increase in R value (R = [P13][Tf2N] or [N3111][Tf2N]/[BHD][AOT]) at a temperature of 25 °C for both the systems. This is attributed to the movement of the probe molecules from the interface to the pool of the microemulsion. However, the rotational relaxation time of the probe molecules (C-480) increases with increasing value of R as the pool of the microemulsion is more viscous compared to the interfacial region. Besides these, for the first time, we have measured the diffusion coefficients of these novel aggregates applying fluorescence correlation spectroscopic technique. The decrease in diffusion coefficients (Dt) with increase in R confirms the swelling of the microemulsions with addition of RTILs.
Bibliographical noteFunding Information:
N. S. is grateful to SERB, Department of Science and Technology and Council of Scientic and Industrial Research (CSIR), Government of India for generous research grants. C. B. is thankful to UGC; N. K. and D. B. are thankful to IIT Kharagpur and A. R. is thankful to CSIR for the research fellowships
© The Royal Society of Chemistry 2016.