title: On the effect of pH on spreading of surfactant solutions on hydrophobic surfaces.
abstract: Surfactants are invaluable in a number of agricultural applications in products such as pesticides and herbicides. In these products, surfactants are very often used in conjunction with acidifiers in order to improve their half-life. In this paper, we investigate how the change in pH affects surfactant wetting and spreading. We compare the performance of a conventional surfactant, Triton X-100, with that of a trisiloxane superspreader, Silwet L-77, on a number of polymer coated surfaces exhibiting various degrees of hydrophobicity. Silwet L-77 in water based solutions showed very good wetting capability on all surfaces. However, its wetting ability was drastically reduced with the addition of acetic acid. On the other hand, Triton X-100 was not affected by the addition of acid and exhibited the same spreading behaviour as in water-based solutions.
authors.affiliation: Institute for Materials and Processes, School of Engineering, The University of Edinburgh, Kings Buildings, Edinburgh EH9 3JL, United Kingdom.
authors.forename: Jovana
authors.initials: J
authors.lastname: Radulovic
authors.forename: Khellil
authors.initials: K
authors.lastname: Sefiane
authors.forename: Martin E R
authors.initials: ME
authors.lastname: Shanahan
mesh_terms: D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D017830:Octoxynol; D017646:Organosilicon Compounds; D013501:Surface-Active Agents / Q000737:chemistry*; D017155:Wettability
chemical_list: D017646:Organosilicon Compounds; D013501:Surface-Active Agents; C473569:silwet L-77; D017830:Octoxynol