The surface tension and contact angle measurements were carried out using a DSA 100E analyzer (Krüss, Germany) at 25 °C. According to the manufacturer, the measurement accuracy of this instrument amounts to ±0.001 mN m -1 . The surface tension was determined using the drop shape method. Basically, the principle of this method is to form an axisymmetric drop at the tip of a needle of known diameter. The image of the drop is taken with a CCD camera and digitized. The surface tension (γ, mN m -1 ) was calculated according to the results of the drop profile analysis according to the Laplace equation. The value of the surface tension and contact angle allowed for calculation of the CMC and surface tension at CMC (γCMC) based on the plot γ vs log C using a linear regression analysis method. The temperature was controlled using a Fisherbrand FBH604 thermostatic bath (Fisher, Germany, accuracy ±0.1 °C). The determination of the contact angle (CA) was based on the sessile drop method. The drops of solution are deposited on a solid hydrophobic surface (paraffin). The images of the drops were taken with a CCD camera, digitized and evaluated using Young-Laplace fitting. The CA was determined as the slope of the tangent line at the contact point between the 3 phases (solution, paraffin surface, and air). The measured error of the CA determination in this method is estimated to be less than 0.1° by the manufacturer. Where wdic is mass fraction of dicamba anion.