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Download fileSurface Tension, Viscosity, and Refractive Index of Sodium Dodecyl Sulfate (SDS) in Aqueous Solution Containing Poly(ethylene glycol) (PEG), Poly(vinyl pyrrolidone) (PVP), and Their Blends
journal contribution
posted on 2017-06-28, 17:20 authored by Ram Singh, Suvarcha Chauhan, Kundan SharmaTaking into consideration the importance
of the polymer–surfactant
system, in present manuscript we discuss the intermolecular interactions
present in solution containing sodium dodecyl sulfate (SDS) in six
different solvent concentrations of polymer and their mixtures in
their mass ratio [1 g of PEG (m1), 0.8:0.2
PEG/PVP (m2), 0.6:0.4 PEG/PVP (m3), 0.4:0.6 PEG/PVP (m4), 0.2:0.8 PEG/PVP (m5), and 1
g of PVP (m6) in 100 mL of distilled water]
having a molal concentration corresponding to 1.66 mmol·kg–1, 1.38 mmol·kg–1, 1.10 mmol·kg–1, 0.81 mmol·kg–1, 0.53 mmol·kg–1, and 0.25 mmol·kg–1, respectively.
It suffices to mention here that the concentration (molality) corresponds
to the total polymer content in the solution. All of the measurements
were carried out at three different temperatures, that is, 293.15,
303.15, and 313.15 K. The whole experiment was carried out with techniques
like surface tension, viscosity, and refractive index measurements.
Different parameters of relevance like surface excess (Γmax), minimum area per molecule at air–water interface
(Amin), relative viscosity (ηr), viscous relaxation time (τ), and limiting dielectric
constant (ε∞), and so forth have been evaluated
from surface tension, viscosity, and refractive index measurements.
This persistence of the surface tension (γ) beyond the critical
micelle concentration (CMC) appears to suggest that the aggregate
formation in the presence of the PEG or PVP or their blends is sufficiently
large. The close approximated value of relative viscosity to the unity
implies that the conformational changes in the polymer are minimal.
The refractive index measurements further reveal that the overall
polarizability of the studied systems increases with an increase in
the amount of polymer in the solution.