title: A novel ionic liquid-in-oil microemulsion composed of biologically acceptable components: an excitation wavelength dependent fluorescence resonance energy transfer study.
abstract: In this work we have reported the formulation of a novel ionic liquid-in-oil (IL/O) microemulsion where the polar core of the ionic liquid, 1-ethyl-3-methylimidazolium n-butylsulfate ([C2mim][C4SO4]), is stabilized by a mixture of two nontoxic nonionic surfactants, polyoxyethylene sorbitan monooleate (Tween-80) and sorbitan laurate (Span-20), in a biological oil phase of isopropyl myristate (IPM). The formation of the microemulsion droplets has been confirmed from the dynamic light scattering (DLS) and phase behavior study. To assess the dynamic heterogeneity of this tween-based IL/O microemulsion, we have performed an excitation wavelength dependent fluorescence resonance energy transfer (FRET) from coumarin 480 (C480) to rhodamine 6G (R6G). The multiple donor-acceptor (D-A) distances, ∼15, 30, and 45 Å, obtained from the rise times of the acceptor emission in the presence of a donor can be rationalized from the varying distribution of the donor, C480, in the different regions of the microemulsion system. With increasing the excitation wavelength from 375 to 408 nm, the contribution of the rise component of ∼240 ps which results the D-A distance of ∼30 Å increases significantly due to the enhanced contribution of the C480 probe molecules closer to the acceptor in the ionic liquid pool of the microemulsion.
authors: Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India.
authors: Sarthak
authors: S
authors: Mandal
authors: Surajit
authors: S
authors: Ghosh
authors: Chiranjib
authors: C
authors: Banerjee
authors: Jagannath
authors: J
authors: Kuchlyan
authors: Debasis
authors: D
authors: Banik
authors: Nilmoni
authors: N
authors: Sarkar
mesh_terms: D003374:Coumarins / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer; D006601:Hexoses / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D009226:Myristates / Q000737:chemistry; D009821:Oils / Q000737:chemistry*; D011136:Polysorbates / Q000737:chemistry; D011807:Quinolizines / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D014783:Viscosity
chemical_list: D003374:Coumarins; D004655:Emulsions; D006601:Hexoses; D007093:Imidazoles; D052578:Ionic Liquids; D009226:Myristates; D009821:Oils; D011136:Polysorbates; D011807:Quinolizines; D012235:Rhodamines; C026188:rhodamine 6G; C573700:coumarin 480; C008205:isopropyl myristate; C014822:sorbitan monolaurate; C518739:1-ethyl-3-methylimidazolium