关键词: 溶液, 表面张力, 水稻, 润湿展布

Abstract: The surface tension and spreading characteristics of monosultap ME drops on rice leaf were studied using 50-1000 mg/L 20% monosultap ME, which comprised technical product of monosultap ME, synergist, mineral oil, and three non ion surfactants. Results showed that the surface tension of monosultap ME at 50 mg/L, 100 mg/L, 200 mg/L, 500 mg/L and 1000 mg/L were smaller than the critical surface tension of rice leaf. The contact angles of the drops of these solution were about 135° when the drops dropped onto rice leaf. As time went on, the contact angle became smaller, and the higher the concentration was, the faster the contact angle became small. Finally, the drops of monosultap ME at 200 mg/L, 500 mg/L and 1000 mg/L spread completely because the surfactant was over CMC (critical micelle concentration) in these solution and the drops at 50 mg/L and 100 mg/L could not spread eventually because the surfactant did not reach the CMC. Small drops of water tend to be attracted to form larger drops when they were near enough on rice leaf due to surface tension, but the drops of monosultap ME at 500 mg/L could not form larger ones and they could be distributed over rice leaf when they dropped on to it.

Key words: solution, surface tension, rice, wet spreading