Aggregation and Rheological Behavior of the Lavender Oil–Pluronic P123 Microemulsions in Water–Ethanol Mixed Solvents

Abstract

The effect of lavender oil on aggregation characteristics of P123 in aqueous-ethanolic solutions is investigated systematically by DLS, SANS, and rheology. The solubilization capacity of the P123 based formulations toward Lavender oil increased by increasing P123 concentration. The study unveiled the importance of the short chain alcohol-ethanol, as solubilization enhancer. The apparent hydrodynamic radius (R) increased significantly with an increase in lavender oil concentration up to maximum oil solubilization capacity of the copolymer at a particular ethanol concentration. DLS measurements on 5, 10, and 15 wt% P123 in the presence of 25% ethanol revealed the presence of large-sized micellar clusters in addition to the oil swollen micelles. The core size (R), radius of hard sphere (R), and aggregation number (N) obtained from SANS profiles showed considerable enhancement with the addition of lavender oil confirming penetration of oil inside the copolymer. Rheological studies showed that viscosity also increased significantly with the addition of lavender oil near the maximum loading limit of the P123 concentration. Quite interestingly, the sol-gel transition temperature displayed a strong dependence on both P123 as well as oil concentration and decreased almost linearly by increasing oil concentration. This study demonstrates the use of a biocompatible and temperature sensitive self-assembled P123 based formulation for lavender oil solubilization that can be beneficial in the cosmetic industry wherein controlled release of fragrances and so forth is demanded.

Micellization of Pluronic P123 in Water/Ethanol/Turpentine Oil Mixed Solvents: Hybrid Particle–Field Molecular Dynamic Simulation

“…Adding 15% ethanol into the system caused a reduction of the size of micelles, and, at the same time, an increase of the fraction of micelles composed of a smaller number of P123 beads. Unlike water, ethanol is considered a good solvent for P123, as confirmed by the reduction of micelle’s radius of gyration <Rg>=2.304 nm (system (I)), compared with <Rg>=4.129 nm calculated at 5% P123 in water [18,20]. For the system (IV) of 5% P123, 15% ethanol and 1.5% oil, the percentage of free P123 chain is above 0.2.…”

“…The main goal of the study was to find the effect of ethanol on the micellization of Pluronic P123. To compare the simulation results with the experimental results of [20], the volume concentration of P123 was chosen by 5 % and the temperature of systems was kept at 303K. Furthermore, ethanol, at the two different concentrations of 15% and 25% was chosen, and the two different systems are shown in Table 2 (I), and (II), respectively.…”

“…The grid size was set to 2.1 nm, and the density field was updated every 300 time steps (Update frequency has been tested in several of our previous papers and guarantees reasonable results with respect to finer methods [35,36,37,38,39,41]. ) The NVT ensemble was chosen, the temperature was kept constant at 303K, the same as in the experiments of Reference [20], using the Andersen thermostat with a collision frequency of 20 ps −1 . The total simulation step was 8 × 10 7 steps, which corresponds to the real time 2.4 µs.…”

“…Furthermore, the effect of mixed solvents on the aggregation of P123 [17] and the phase behavior of P123 in mixed ethanolic solvents has been the subject of several studies [18,19]. Very recently, Chat et al successfully investigated the aggregation features of P123 in the presence of lavender oil and ethanol using dynamic light scattering, small angle neutron scattering, and rheology [20]. They showed that lavender oil assisted aggregation characteristics of Pluronic P123 in the mixed solvents of ethanol and water [20].…”

“…Very recently, Chat et al successfully investigated the aggregation features of P123 in the presence of lavender oil and ethanol using dynamic light scattering, small angle neutron scattering, and rheology [20]. They showed that lavender oil assisted aggregation characteristics of Pluronic P123 in the mixed solvents of ethanol and water [20]. Furthermore, Ganguly et al studied tea tree essential oil (TTO) on the properties of aqueous solutions of Pluronic P123 and the effect on micellar solubilization.…”