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Estimation of Micropolarity and Microviscosity of Pluronic F127–Surfactant Mixed Systems Using Fisetin as a Fluorescent Molecular Probe
Author(s) -
Mishra Jhili,
Mishra Ashok Kumar
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201803924
Subject(s) - microviscosity , poloxamer , pulmonary surfactant , fluorescence anisotropy , differential scanning calorimetry , chemistry , analytical chemistry (journal) , micelle , sodium dodecyl sulfate , glass transition , materials science , chemical engineering , chromatography , organic chemistry , aqueous solution , polymer , thermodynamics , biochemistry , physics , membrane , engineering , copolymer
Abstract Surfactant induced changes in the transition temperature of Pluronic F127 have been studied using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and fluorescence spectroscopy. The analysis shows that ionic surfactants (cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS)) significantly alter the transition temperature of PF127, whereas the effect of a nonionic surfactant (Tween20) is not significant. The sol‐gel transition temperature decreases from PF127 (22 °C) to PF127+TW20 (21 °C) to PF127+CTAB (18 °C), whereas there is no sol‐gel transition temperature observed for PF127+SDS. Using the anionic emission and fluorescence anisotropy value of fisetin, the local polarity and microviscosity in the immediate neighbourhood of fisetin in pluronic‐surfactant systems have been estimated. Rotational correlation time along with the time‐resolved fluorescence anisotropy study gives additional information about the variation in medium microviscosity (PF127) with temperature in the absence and presence of surfactants. Variation in both polarity and microviscosity of the PF127‐surfactant mixed systems follows a reverse trend at sol and gel phases. Fluorescence lifetime studies indicate that fisetin molecules distribute in the different microdomains of PF127‐surfactant mixed systems. The local environmental heterogeneity at different microdomains of PF127‐surfactant mixed system is confirmed from lifetime distribution analysis of fisetin FT* emission.