Temperature controlled surface hydrophobicity and interaction forces induced by poly (N-isopropylacrylamide)

Probing the stability of sterically stabilized polystyrene particles by centrifugal sedimentation

“…Subsequently, the mixture was heated to 70°C. Once temperature equilibration was reached, a mixture of 40 5.0 g styrene and 0.05 g AIBN was injected dropwise into the reaction flask. The polymerization was allowed to proceed for 24 hours under nitrogen at 300 rpm.…”

“…Subsequently, as the centrifugal field is increased over time, the particles, which are already in a strongly close packing arrangement, are prevented from further particle rearrangement. 40 Hence, any additional centrifugal force is unable to compress the particle bed further. In contrast, above T c , the solvency of PEGMA stabilizers is compromised, resulting in instability of the polystyrene particles and aggregation into larger structures (Figure 2b).…”

“…Ultimately, this is linked to an increase in the depth of the attractive interaction minimum with increasing electrolyte, affecting the particle 35 aggregation rate and size/density of aggregates formed. 7,36 Further increases in the applied centrifugal field at increments of 500 rpm up to a final speed of 4000 rpm showed a characteristic collapse profile of the sediment beds with the degree of collapse for these beds increasing with increased 40 electrolyte concentrations (~1.8 mm at 1 mM KCl up tõ 5.4 mm at 1 M KCl). The more open bed structure at 1 M KCl clearly allows greater flexibility for the particles to rearrange and exclude the supernatant volume, hence leading to larger particle bed compression.…”

“…organic pigments, oxide nanoparticles, polymeric thickeners, microcapsules, etc.) and include a range of other additives, such as volatile actives, electrolyte, viscosity modifier, humectant 40 amongst others. This makes the formulation of a stable colloidal dispersion laborious and it can also be difficult to judge the colloidal stability in the early formulation stages without performing lengthy 'stability' experiments.…”

Flocculation of flotation tailings using thermosensitive polymers

“…Moreover, Forbes (2011) indicated that PNIPAM may be more efficient than conventional flotation agents. Its copolymers can be used for selective removal of desired mineral (Burdukova et al, 2010b). At the present moment, one may find papers where thermosensitive polymers were used for suspension flocculation (Burdukova et al, 2011;Deng et al, 1996;Forbes, 2011;Ghimici and Constantin, 20011;Kuźnik et al, 2010;Lemanowicz et al, 2012;Mori et al, 2013;Sakohara et al, 2008;Sakohara et al, 2013), nanoparticles stabilization (Budgin et al, 2012;Gong et al, 2012) or heavy metal ion removal (Tokuyama et al, 2010).…”