Impacts of composition of short chain alcohols/ urea and temperature change on the interaction of polyvinyl alcohol and sodium dodecyl sulfate: Conductivity and DFT investigations

Abstract

Herein, the conductivity measuring approach was used to investigate the aggregation of polyvinyl alcohol (PVA) with sodium dodecyl sulphate (NaDS) in H2O and H2O + alcohols (EtOH,1-PrOH, 2-PrOH)/ urea environments at various temperatures. The extent and nature of interaction between NaDS and PVA has been characterized from the achieved micellar parameters and energetics of the aggregation process. The micelle development has been characterized from the break point achieved in the conductivity vs. conc. of NaDS plots. At 303.15 K, the single CMC values of the NaDS + PVA mixture were decreased with increasing the amount of PVA (<0.5 % (w/w) PVA) while two CMC values were acquired at 0.5 % (w/w) PVA. The CMC values have been observed to change significantly with the concentrations of alcohols while an increasing trend in the CMC values has been detected in alcohols media above 6 % (w/w) composition. In water and aq. EtOH/urea solutions, the CMC values initially decline, reaches its lowest point, and then increases when the temperature is increased. In aq. 1-PrOH and 2-PrOH solutions, the CMC values demonstrate the enhancing fashion with increasing temperature. In all cases, negative ∆Gmo values were found, indicating spontaneous aggregation phenomena. The measurements of ∆Hmo and ∆Smo indicate that the PVA molecule interacts with NaDS through ion-dipole and hydrophobic interactions. Furthermore, compensation temperature (Tc) and intrinsic enthalpy gain (∆Hm0,*) for the studied system were measured and described with proper reasoning. In addition, the properties of complex formation and structural analysis, band gaps analysis, chemical hardness and UV-Vis spectral study of the NaDS, PVA, and NaDS + PVA mixed system with and without additive have been explored by using DFT technique.