Thermoosmotic transfer of sterically stabilized ferrofluid particles in non-isothermal capillary porous layer

Non-isothermal mass transfer of ferrocolloids through porous membrane

“…As seen, the present measurements of particle separation through porous layer give significantly lower values of both the coefficients. It is interesting to note that a strong reduction of thermal separation rate was observed also in another filtration experiment [2].…”

“…Recently an unusually high thermophoretic mobility of nanoparticles is established [1], as well as significant changes in their thermophoretic separation in capillary porous media [2] and strong intensification of particle thermal transfer through a grid in the presence of magnetic field [1,3]. Besides the basic interest, these novel effects have a practical importance for many applications.…”

Effect of an excess of surfactant on thermophoresis, mass diffusion and viscosity in an oily surfactant-stabilized ferrofluid

“…From this large hydrodynamic volume fraction, we can calculate a mean hydrodynamic radius of the dispersed objects by making several hypothesis on the shape of these objects. For example (i) assuming that the NPs are individualy dispersed, then [74]: (15) or (ii) assuming that two NPs are enclosed in each dispersed object forming dimers of NP, then: 3 nm is too large to be associated with a monolayer coating of magnetic NPs [52], and the hypothesis (ii) of dispersed dimers with d…”

“…Previous research has shown that oily ferrofluids in a porous environment can present a decrease in thermally induced particle transport [15] for a wide range of such colloidal dispersions [16,17]. It has also been shown that surfactant addition further decreases Soret coefficient in a porous medium and that, at a sufficient concentration of excess surfactant, the particle transfer direction in a temperature gradient can be inverted [17].…”