Surface tension:

The surface tension of silicone surfactant is much lower than the non-silicone ones, and this will lead to the big gap in the contact angle,generally positively related, see table as below. 

Contact Angle:

Usually the contact angle is negatively related to the wetting speed and coverage diameter on the surface, see table as below. 

Wetting speed and diameter: 

PET is a hydrophobic surface.The good performance of silicone surfactant on such surface make it possible to have good market in agriculture. 

The waxy layer of crop leaves are also hydrophobic. Genrally agrochemicals will find it hard to enter inside the leaf structure by stomatal absorption. And the wetting speed is slow, the spreading coverage is not big. The drops may slide off the leaf surface or big drop may even bounce out, thus leads to the pesticide waste and efficacy not meet the expectation. 

With the help of silicone surfactant, the agrochemicals can spread on the leaf surface, then go into the small part of crops and weeds, and maximize the efficacy. 

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