Influences of NaCl and Na2SO4 on the Micellization Behavior of the Mixture of Cetylpyridinium Chloride + Polyvinyl Pyrrolidone at Several Temperatures

Abstract

Herein, the conductivity measurement technique is used to determine the interactions that may occur between polyvinyl pyrrolidone (PVP) polymer and cetylpyridinium chloride (CPC) surfactant in the presence of NaCl and Na2SO4 of fixed concentration at variable temperatures (298.15–323.15 K) with an interval of 5 K. In the absence or presence of salts, we observed three critical micelle concentrations (CMC) for the CPC + PVP mixture. In all situations, CMC1 values of CPC + PVP system were found to be higher in water than in attendance of salts (NaCl and Na2SO4). Temperature and additives have the tendency to affect counterion binding values. Various physico-chemical parameters were analyzed and demonstrated smoothly, including free energy (ΔG0m), enthalpy (ΔH0m) and entropy change (ΔS0m). The micellization process is achieved to be spontaneous based on the obtained negative ΔG0m values. The linearity of the ΔHmo and ΔSmo values is excellent. The intrinsic enthalpy gain (ΔH0*m) and compensation temperature (Tc) were calculated and discussed with logical points. Interactions of polymer hydrophobic chains or the polymer + surfactant associated with amphiphilic surface-active drugs can employ a strong impact on the behavior of the gels.

Study on the association and phase separation behavior of surfactants and promethazine hydrochloride: impact of ammonium electrolytes

“…The degree of counterion bounds to micelles ( β ) can be obtained by the subtraction of α from the unity. 61 The effect of three ammonium salts, such as NH 4 Cl, NH 4 NO 3 and (NH 4 ) 2 SO 4 , on the variables associated with the aggregation of surfactant-drug systems was examined in the current investigation. The concentrations of NH 4 Cl, NH 4 NO 3 and (NH 4 ) 2 SO 4 were chosen in the range of 0.4911–12.00 mmol kg −1 , 0.5221–12.12 mmol kg −1 and 0.5333–4.097 mmol kg −1 , respectively, while the values of ionic strength ( I ) of respective ammonium salts are provided in Table 2 .…”

A recent overview of surfactant–drug interactions and their importance

“…The CMC values of the drug surfactant system were found to be greater in an aqueous solution than in the presence of NaCl and Na 2 SO 4 in all circumstances due to the repulsive interactions, 65 which increased the diffusion coefficient and reduced the dimension of the micelles. 66 When non-ionic surfactant turbidity in solution becomes apparent to the unaided eye, it is referred to as a cloud. The cloud point (CP) is dened as the temperature at a certain point or even above it where phase separation occurs.…”

“…The CMC values of the drug surfactant system were found to be greater in an aqueous solution than in the presence of NaCl and Na 2 SO 4 in all circumstances due to the repulsive interactions, 65 which increased the diffusion coefficient and reduced the dimension of the micelles. 66 …”