title: Exploring the photophysics of curcumin in zwitterionic micellar system: an approach to control ESIPT process in the presence of room temperature ionic liquids (RTILs) and anionic surfactant.
abstract: In this manuscript, we have modulated the photophysical properties of curcumin in a zwitterionic (N-hexadecyl-N,N-dimethylammonio-1-propanesulfonate (SB-16)) micellar aggregates with addition of room temperature ionic liquids (RTILs) as well as commonly used anionic surfactant (SDS), using steady-state and time-resolved spectroscopic techniques. To modulate the photophysics, first we studied its interaction with an SB-16 micellar system, then to further exploit its photophysics, three RTILs (EmimES, EmimBS, EmimHS) with variation of alkyl chain lengths as well as SDS were used. It is observed that the rate of degradation of curcumin is drastically decreased after partitioning into the zwitterionic micellar system. It is shown that the dynamics of excited state intramolecular proton transfer (ESIPT) processes can be controlled by using those RTILs and SDS. Our study also reveals that the hindrance of nonradiative processes of curcumin, i.e., ESIPT is more pronounced in the case of RTIL containing a long alkyl chain compared to a small one. However, most interestingly the addition of long chain (dodecyl) anionic surfactant (SDS) promotes the ESIPT process of curcumin. We have also studied the effect of the addition of inorganic salt and compared the results with RTILs. The present work demonstrates an effort to decipher the photophysics of curcumin in zwitterionic micellar systems by monitoring its excited state dynamics.
authors.affiliation: Department of Chemistry, Indian Institute of Technology , Kharagpur 721302, West Bengal, India.
authors.forename: Chiranjib
authors.initials: C
authors.lastname: Banerjee
authors.forename: Surajit
authors.initials: S
authors.lastname: Ghosh
authors.forename: Sarthak
authors.initials: S
authors.lastname: Mandal
authors.forename: Jagannath
authors.initials: J
authors.lastname: Kuchlyan
authors.forename: Niloy
authors.initials: N
authors.lastname: Kundu
authors.forename: Nilmoni
authors.initials: N
authors.lastname: Sarkar
mesh_terms: D000838:Anions / Q000737:chemistry; D003474:Curcumin / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D052578:Ionic Liquids / Q000737:chemistry*; D007700:Kinetics; D008823:Micelles; D011522:Protons; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
chemical_list: D000838:Anions; D052578:Ionic Liquids; D008823:Micelles; D011522:Protons; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D003474:Curcumin