农业工程学报2017，Vol.33Issue(3)：81-87,7.DOI:10.11975/j.issn.1002-6819.2017.03.011
烷基聚葡糖苷液滴在黄瓜叶面的润湿状态及动态铺展行为
Wetting state and dynamic spreading behavior of alkyl polyglycoside drop on cucumber leaf surface
摘要
Abstract
Improving the wettability of spraying liquid on the target crop surface is one of the effective ways for enhancing the utilization efficiency of pesticide.When the spray liquid reached the surface of target crop,will occur series dynamic process including deposition,retention,spread,penetration,etc.These behaviors of dynamic wetting will decide spraying liquid how to transfer to biological organisms,and make directly influence of the pesticide.As entering the 21st century,the dynamic wetting behavior of liquid on target interface has become a very active research direction in the pesticide application field,which is one of the important research contents of precision spraying technology.Alkyl Polyglycoside (APG) is recognized as an internationally preferred green functional surfactant,it has attracted special attention because of its high surface activity and ecological security.In recent years,more and more domestic and foreign researchers have done a lot of work in improving APG pesticide additives,which focusing on the preparation,modification and its synergism mechanism,and achieved obvious achievements.In order to investigate the dynamic wetting behavior of APG additive solution on the cucumber leaf surface and its change of dynamic contact angle,APG solution of 9 mass fraction (14.35％-85.78％) and their dynamic wetting parameters which includes surface tension (γ),contact angle (θ),dynamic contact angle (θd),advancing contact angle (θa),receding contact angle (θr),spreading diameter (φ) were measured by using surface tension and contact angle measuring instrument based on hanging drop method and sessile drop method.The contact angle hysteresis and spreading driving force are analyzed and deduced based on Tanner rule,and the relationship curve between spreading diameter (φ),power value (α) and time (t) were fitted by the application of the power law.With digital image processing technology,the process of dynamic wetting was recorded by CCD camera and their dynamic wetting parameters were obtained and extracted from drop images features.The results showed that these 9 APG solutions' surface tension were within a narrow range from 27.96 to 29.73 mN·m-1,but their contact angle were varied from 11.35° to 34.20° in a wide range.It indicated contact angles did not change radically with the increasing concentration of APG solution.As a kind of easily wetting leaves,advancing contact angle (θa) of deionized water drop on cucumber leaf surface increased by 7.54°,while receding contact angle (θr) decreased by 22.85°,its contact angle hysteresis (△θ) is 46.89° within 10 s.The dynamic wetting process reflects the interface behavior of cucumber leaves accords with the basic law of rough surface contact angle hysteresis.Dynamic contact angle of APG solution of different mass fraction on cucumber leaf surface fell sharply in the first 1 s,then decreased steadily and gradually tended to be stable (1-10 s).The relationship between the spreading diameter (φ) and time (t) were better conformed to the power law.The power value of APG solution fitting curves were within the range from 0.01 to 0.08,the coefficient C were between 2.787 3 and 3.567 3,the APG solution of lower concentration showed a higher fitting degree.It can be inferred that the dynamic surface tension is the dominant spreading driving force on cucumber leaf surface (interface).This paper provides theoretical basis and technical support for pesticide spraying with cucumber as target crop and APG as adjuvant.关键词
接触角/润湿/液滴/烷基聚葡糖苷,黄瓜叶片,动态润湿,Tanner法则Key words
contact angle/wetting/drops/alkyl polyglycoside, cucumber leaf, dynamic wetting, Tanner law分类
农业科技引用本文复制引用
张红涛,陆军,魏德云,胡玉霞..烷基聚葡糖苷液滴在黄瓜叶面的润湿状态及动态铺展行为[J].农业工程学报,2017,33(3):81-87,7.基金项目
国家自然科学基金资助项目(31671580) （31671580）
浙江省一流学科B类(农业工程)建设项目(浙教高科[2015]126号) （农业工程）
浙江省自然科学基金项目(LY16C130008) （LY16C130008）
河南省科技攻关项目(162102110112) （162102110112）
华北水利水电大学教学名师培育项目(2014108) （2014108）
