SYMPOSIA PAPER Published: 01 November 2022

Measuring Surface Wetting of Adjuvants and Related Agricultural Products by Semi-Automated Goniometry and Precision Tilt


Over the past decade, environmental concerns over immoderate pesticide usage, coupled with concerns over pesticide resistance, have fueled a booming adjuvant market to maintain sufficient crop protection; however, conventional laboratory techniques for determining the efficacy of these adjuvants are lacking and outdated. This paper presents a new experimental paradigm for both characterizing and quantifying the spreading behavior of a liquid agricultural product through semi-automated goniometry. Method A overcomes the error and bias in traditional, single-valued contact angle measurements by capturing the transient variability of contact angle via a high-resolution video camera. Method B utilizes numerical analysis to isolate the most stable contact angle (MSCA) of the liquid-substrate system. Experimentally, the incorporation of an automated tilting mechanism allows the goniometer to capture instances of stick-slip activity from a gradually tilted drop. Measurements of critical tilt angles at two distinct initial contact angles are fitted by linear regression to interpolate the MSCA of the system. Spreading work is then calculated from the known value of surface tension and the derived MSCA and reported against a common substrate and base liquid (water), enabling a modern industry standard for measuring, calculating, and interpreting the effectiveness of wetting agents.

Author Information

Padmanabha, Akaash
Helena Agri-Enterprises LLC, Collierville, TN, US
Bear, Jennifer
Helena Agri-Enterprises LLC, Collierville, TN, US
Gum, Emily
Helena Agri-Enterprises LLC, Collierville, TN, US
Milholland, Karla
Helena Agri-Enterprises LLC, Collierville, TN, US
Cox, Michael
Helena Agri-Enterprises LLC, Collierville, TN, US
Hayes, Amanda
Helena Agri-Enterprises LLC, Collierville, TN, US
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Pages: 1–10
DOI: 10.1520/STP164120210060
ISBN-EB: 978-0-8031-7730-7
ISBN-13: 978-0-8031-7729-1