Wetting Behavior and Maximum Retention of Aqueous Surfactant Solutions on Tea Leaves

Abstract

In this research, the maximum retention and wetting behavior of surfactant solutions (N-200, N-300, Tween-80, Morwet EFW, DTAB, SDS) on the surfaces of tea leaves was investigated based on surface free energy, surface tension, the contact angle, adhesion work, and adhesion force. The results showed that the contact angles of all surfactant solutions were kept constant with low adsorption at the tea leaf–liquid interfaces below 0.005%. With an increase in concentration, the contact angle of Tween-80 decreased sharply because the adsorption of molecules at the solid–liquid interfaces (ΓSL’) was several times greater than that at the liquid–air interfaces (ΓLV). Adhesion work decreased sharply and then reached a minimum at the critical micelle concentration (CMC), but then increased until reaching a constant. Moreover, a high adhesion force did not indicate better wettability, as it does with rose petals and peanut leaves. For tea leaf surfaces, an increase in the contact angle brought about an increase in the adhesion force. In addition, the maximum retention for Morwet EFW is at different concentrations compared to N-200, N-300, Tween-80, DTAB, and SDS, where the maximum retention of Morwet EFW on tea leaves was 6.05 mg/cm2 at 0.005%.According to the mechanisms of wetting behavior on plant surfaces, a recipe for pesticide formulation can be adjusted with better wettability to reduce loss, improve utilization efficiency, and alleviate adverse effects on the environment.

Optoacoustic/Fluorescent/Acoustic Imaging Probe Based on Air-Filled Bubbles Functionalized with Gold Nanorods and Fluorescein Isothiocyanate

“…All measurements were performed at room temperature. Surface tension values obtained for the Tween 80 solution (60.9 mg/mL) and Span 60 solution (20 mg/mL) at early surface age (<1 min) of the pendant drop agree with previous reports. − As one can see in Figure a, the lowest value of the last 2 min surface tension average (31.6 mN/m) corresponded to a molar ratio of 1:3, which was chosen as the optimal one for air-filled bubble preparation. This molar ratio differed from the values presented previously because of modifying the method for obtaining bubbles.…”

Preparation of a Chlorantraniliprole–Thiamethoxam Ultralow-Volume Spray and Application in the Control of Spodoptera frugiperda

“…If the pesticide formulation has better adhesion on the crop leaves, it can be retained on the crop leaves more, thereby improving the utilization rate of the pesticide and reducing waste. 40 The maximum retention measurement results of the six samples and the analysis of the significant difference between the test results are shown in Figure 4 . The maximum retention of the five ULV sprays is significantly different to that of the reference product (7.79 mg/cm 2 ).…”

Effect of Adjuvant on Glyphosate Effectiveness, Retention, Absorption and Translocation in Lolium rigidum and Conyza canadensis

“…Plant species present different wettability in their leaves, due to a different leaf architecture such as leaf roughness and wax [23]. When roughness is high, the wettability remains low [24]. Under this concept, plant species' surfaces can be classified from easy-to-wet through to difficult-to-wet, describing why some plants show very non-wetting properties and lead to a low retention of the sprayed liquids.…”