Adsolubilization of 2-naphthol into adsorbed layer of PEO–PPO–PEO triblock copolymers on hydrophilic silica

Adsolubilization of 2-naphthol into adsorbed layers of triblock PEO–PPO–PEO copolymers on hydrophobic silica particles

“…In fact, we demonstrated in our previous publication [25] that adsolubilization of 2-naphthol does take place into the adsorbed Pluronics layers on hydrophilic silica particles, as expected, and the adsolubilization amount is particularly dependent on the hydrophilic/lypophilic balance (HLB) of the copolymers. Indeed, after rinsing of the particles precoated with the more hydrophobic Pluronic surfactants, the desorbed amount of the Pluronics was estimated to be less than 10% of the adsorbed amount.…”

“…It is noted that 2-naphthol does adsorb onto the hydrophobic surface even in the absence of the surfactants. Since the amount of 2-naphthol itself adsorbed onto hydrophilic silica particles was observed to be negligible [25], the adsorption onto the hydrophobic silica particles would be driven by the hydrophobic interaction between the solute and the surface. This adsorption did not cause any significant changes in the dispersion stability of the suspensions (data not shown).…”

“…The surfactant concentration in the supernatant was evaluated by referring to a method developed by Nuysink and Koopal [30]. The experimental procedure is given in our previous publication [25].…”

“…This desorption will necessarily result in subsequent release of the adsolubilized solutes. From this point of view, adsolubilization into the adsorbed layers of triblock PEO-PPO-PEO copolymers (Pluronics) on hydrophilic silica particles was studied previously [25]. As is well known, Pluronic surfactants are chemically synthesized triblock copolymers and the physicochemical properties in aqueous/nonaqueous solutions are possibly to be controlled by adjusting synthesis parameters such as EO/PO ratio and overall copolymer molecular weight.…”

Effect of Pluronics and surfactant adsorption onto dolomite suspension zeta potential and stability

“…The suspensions were shaken and after reaching the equilibrium the samples were centrifuged and the supernatants were analyzed. The concentration of Pluronics in the supernatants was measured according to tannic acid method described by Tsurumi et al [15]. The complexation between tannic acid and PEO block of Pluronic gives turbidity.…”