Active ingredient deposition as a whole during foliar spray application was studied by means of microscopic and macroscopic methods. High‐speed photography of the impact of spray droplets showed that rebound from reflective plant surfaces was reduced only with surfactant concentrations well above the critical micelle concentration. These results correlate with laboratory spraying experiments to determine quantitatively the retention of spray solutions. The dynamic interaction between droplet and foliage seemed to be specifically dependent on surfactant structure, concentration and the distribution of isomers or by‐products in the technical product. Rough surfaces with epicuticular wax crystals were difficult to wet; the orientation of the leaf, however, had little influence on retention. Apolar artificial surfaces retained water rather well and are therefore unsuitable as model surfaces for reflective leaves. Measurement of dynamic surface tension at 100 msec gave a satisfactory correlation with retention values in the case of liquids containing surfactant but failed to predict the good adhesion of polyvinyl alcohol solutions.
Surface analysis methods like ESCA, AES, SIMS and ISS can provide valuable information on the structure and composition of polymer surfaces. Examples of application are the investigation of surface changes, such as the effects of weathering, etching and corona treatments, and the detection of surface deposits consisting of materials like antistatic agents, lubricants and exuded constituents. Because of their high surface sensitivity and ability to differentiate between surface and bulk phenomena, surface analysis methods are particularly suitable for the investigation of interfaces between polymers and metals, glass fibres, etc., e.g. in radial tyres, cable insulations and capacitor foils. It is pointed out that in these cases the inadequacies of the preparation methods limit the value of the analytical findings more than the inadequacies of the analysis methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.