Organic Additive, 5-Methylsalicylic Acid Induces Spontaneous Structural Transformation of Aqueous Pluronic Triblock Copolymer Solution: A Spectroscopic Investigation of Interaction of Curcumin with Pluronic Micellar and Vesicular Aggregates

This article presents the interaction of curcumin in the microenvironments provided by aggregation of pluronic triblock copolymer P123 into micellar and vesicular assemblies. The formation of vesicles using triblock copolymer P123 and 5-methylsalicylic acid (5 ms) has been successfully characterized by optical spectroscopy light scattering measurement and eventually microscopic techniques. Besides to make a comparative study between the polymeric micelles we have also investigated the photophysical changes of curcumin in F127 triblock copolymer micelles havin variation in poly(ethylene oxide) (PPO) and poly(propylene oxide) (PEO) unit of polymer chain to taht of P123. Time-dependent UV-vis measeurement suggests that these polymer micelles are able to stabilize poorly water-soluble curcumin by suppressing the degradation rate in micellar nanocavity. However, experimental observations suggest that P123 micelles are more efficient that F127 to perturb excited state intramolecular proton transfer (ESIPT) related nonradiative decay of curcumin. We also observed that rigid and confined microenvironment of P123/5 mS vehicles enhances emission intensity and lifetime of curcumin more compared to P123 micelles. All the observations suggest that modulation of photophysics onf curumin is responsible duw to its interaction with poly(ethylene oxide) or poly(propylene oxide) unit of triblock copolymer.