Prameela, G K S and Kumar, B V N Phani and Reddy, R Ravikanth and Pan, A and Subramanian, J and Kumar, Sugam and Aswal, V K and Kohlbrecher, Joachim and Mandal, A B and Moulik, S P (2017) Vesicle to micelle transition in the ternary mixture of L121/SDS/D2O: NMR, EPR and SANS studies. Physical Chemistry Chemical Physics, 19 (47). pp. 31747-31755. ISSN 1463-9076

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Abstract

Subtle changes in the microstructure and dynamics of the triblock copolymer L121, (ethylene oxide) 5 (propylene oxide) 68 (ethylene oxide) 5 i. e., E5P68E5, and sodium dodecylsulfate (SDS) system in aqueous medium were investigated using high-resolution nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) and small-angle neutron scattering (SANS) methods. NMR self-diffusion measurements helped us to understand the nature of binding of SDS with L121, and the formation of their mixed aggregates. These results showed that even at low SDS] (similar to 2 mM), the addition of L121 stabilized the dynamics of SDS. Furthermore, the increase in SDS] resulted in progressive changes in the diffusion behavior of both SDS and L121. C-13 chemical shift analysis revealed that preferential binding of L121 occurred on the SDS micelle surface. Deuterium (H-2) NMR spin-relaxation data evidenced that the formed mixed aggregates were non-spherical in terms of relaxation rate changes, and slowed the dynamics. The rotational correlation times of mixed aggregates were estimated from EPR analysis. A SANS study indicated the presence of uni-and multi-lamellar vesicles of L121 at low SDS]. The vesicles transformed to mixed L121-SDS micelles in the presence of a higher SDS]. This was supported by the measurements of H-2 NMR spin-relaxation and EPR rotational correlation times.

Item Type:	Article
Subjects:	Microstructure and Characterization
Divisions:	Sensor and Actuator
Depositing User:	Bidhan Chaudhuri
Date Deposited:	31 Jan 2018 09:11
Last Modified:	31 Jan 2018 09:11
URI:	http://cgcri.csircentral.net/id/eprint/4098

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