(1) Interactions between polysoap (potassium salt of alternating maleic anhydride and cetylvinyl ether copolymer) and monosoap (potassium palmitate (KP), laurate (KL), and caprylate (KC)) in aqueous solution, were classified into four groups from the viscosity behavior of the nixed polysoap/ monosoap solutions at constant mixed ratios.
a) The plots of the observed reduced viscosity
vs. polysoap concentration were in straight line and were in parallel to the calculated plots (the summation of the viscosity of the polysoap and the monosoap solution respectively). This would mean the presence of the polysoap/monosoap complexes due to the hydrophobic bonding which had constant compositions and contents.
b) The observed plots were almost flat, while the calculated ones were sloping. This may be attributed to the contraction of the polysoap molecules subsequent to the fixation of counter ions by polysoap anions, similarly to the effect of the addition of potassium acetate (KA) on the viscosity of the polysoap solution.
c) The observed plots were situated on remarkably lower levels than the calculated ones (the KL/polysoap systems in the 4/1 (mol/basemol basis) mixed ratio). This seems to correspond that intermolecular aggregates of the polysoap present in the aqueous polysoap solution were degrated by the adsorption of the monosoap to the polysoap owing to the hydrophobic bonding between them.
d) Distinct maxima occurred in the observed plots (the KC/polysoap systems in the 12/ 1 mixed ratio). It could be considered that the saturated adsorption of KC to the polysoap was attained at the maximum by the hydrophobic bonding between them.
(2) Hydrophobic interactions between polysoap and monosoap were also confirmed from the carbon black dispersion of the mixed polysoap/monosoap solutions in comparison with the mixed polysoap/KA solutions.
(3) The hydrophobic interactions between polysoap and monosoap were governed by the number of chemically-attached soap-like groups of the polysoap, and monosoaps interacted in a less degree with smaller polysoaps.
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