Determination of dynamic spread factor of water droplets impacting on water-sensitive paper surfaces

Abstract

A brief summary of droplets spreading on solid surfaces is given as an introduction to the determination of dynamic spread factors of water droplets with 300–1500 μm diameter impinging on two types of paper surfaces (1) Kodak Linagraph 480 paper and (2) Kodak Kodabromide F.2 paper treated with a pH indicator. The spread factor on the Kodabromide paper was 0.49 for the stated size range whereas the Linagraph paper had a continuously varying spread factor tending to 0.25 at drop diameters above 700 μm. A discussion about measuring spread factors is included as well as the need for such research in areas of pesticide application.