The Relation of Tallowamine Ethoxylates to Dynamic Surface Tension and Field Performance

Abstract

The uptake of active ingredient from sprayed formulations via foliar penetration has been demonstrated to be increased by the use of surfactants. The surfactant may increase the spray solution's ability to wet the leaf surface, or facilitate translocation of the active ingredient through the stomata into the leaf. It has been shown that the structure of surfactants can influence the ability of the surfactant to promote these mechanisms of transport of the active ingredient. The amount of Ethylene oxide in the hydrophilic portion of the surfactant is one such factor that has been linked to the translocation of the active ingredient. Various hydrophobes such as fatty alcohol and nonylphenol, ethoxylated to various degrees, have been used to show the effect. Another such hydrophobe, tallowamine, is ethoxylated and used as a surfactant in water soluble herbicides. In this study, a series of tallowamine ethoxylates of varying degrees of ethoxylation from 2 moles of Ethylene oxide to 20 moles of Ethylene oxide were evaluated to determine the effect of the amount of Ethylene oxide on surface properties. Aqueous solutions of the surfactants were measured at different frequencies for dynamic surface tension using the maximum bubble pressure technique. The reduction of the liquid's surface tension increase wetting and spreading of the liquid onto the foliar surfaces thus facilitating translocation of the active ingredient. By measuring the modification of the surface tension of the liquid versus the Ethylene oxide content of the surfactant, we will support the data previously compiled. Also included in the study will be measurements of the dynamic contact angle of the aqueous solutions on the surface of a leaf, as well as other surfactant properties.