Anomalous attraction between colloidal magnetite and silica spheres in apolar solvents
van Ewijk, GA; Philipse, AP
| HERO ID | 4936560 |
|---|---|
| In Press | No |
| Year | 2001 |
| Title | Anomalous attraction between colloidal magnetite and silica spheres in apolar solvents |
| Authors | van Ewijk, GA; Philipse, AP |
| Journal | Langmuir |
| Volume | 17 |
| Issue | 23 |
| Page Numbers | 7204-7209 |
| Abstract | We demonstrate the existence of an anomalous, strong attraction between small (9 nm) oleic acid-grafted magnetite particles and octadecanol-grafted silica spheres (420 nm) in apolar solvents. This attraction manifests itself by irreversible adsorption of magnetite particles onto silica spheres, with surface coverages up to 30%. This "heteroflocculation" is, quite surprisingly, orders of magnitude slower than a diffusion-limited process. The adsorption can be reversed by transferring covered silica particles to solvents with a higher dielectric constant. The findings practically rule out van der Waals forces or Coulomb forces between any pre-existing surface charges as the source of attraction. |
| Doi | 10.1021/la010102i |
| Wosid | WOS:000172123700006 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |