The effect of an anionic surfactant on the rheology and stability of high volume fraction O/W emulsion stabilized by PVA |
| |
Authors: | P Taylor |
| |
Institution: | (1) Zeneca Agrochemicals, Jealott's Hill Research Station Formulation Section, RG42 6ET Bracknell, Berkshire, UK |
| |
Abstract: | The effect of the addition of an anionic surfactant (sodium dodecyl benzene sulphonate) on the rheology and storage stability of concentrated O/W emulsions stabilized by poly (vinyl alcohol) is reported. It was found that the surfactant markedly reduced the magnitudes of the storage modulii of the emulsions. This could be attributed to a reduction in the interfacial tension resulting from the formation of polyelectrolyte type complexes between the PVA and NaDBS at the O/W interface. The results were compared to the equation (given by Princen) relating concentrated emulsion rheology to the interfacial tension and droplet size. Reasonable agreement was found, though there was a small difference in the constants in the equation given by Princen and those found here. The agreement suggested that the emulsions were deforming above a critical volume fraction and that the rheological properties were dominated by the dilation of the interface during shear. Microelectrophoresis measurements showed that the addition of the surfactant conferred a charge onto the PVA stabilized droplets as a result of the formation of the polyelectrolyte complex. The NaDBS was found to reduce the long-term stability of the emulsions compared to emulsions containing PVA alone. |
| |
Keywords: | Poly(vinyl) alcohol surfactants oil/water emulsions rheology polymer surfactant complexes |
本文献已被 SpringerLink 等数据库收录! |