Marangoni效应是一种液体在界面张力梯度作用下的自发流动行为.液体界面上液体的Marangoni效应在工程技术领域具有重要作用.本文使用硅油作为驱动液体,正十六烷作为被驱动液体,十二烷基硫酸钠溶液作为液体基底,通过高速相机捕捉正十六烷受驱动铺展的整个过程,研究了三相液体系统中液滴的Marangoni效应.实验发现,正十六烷在硅油的驱动下从内向外铺展,形成液体圆环.本文根据正十六烷圆环内、外边界铺展行为,分析了正十六烷内边界和外边界的铺展原理,并研究了滴入硅油体积对于铺展过程的影响.研究发现,正十六烷内边界铺展与单一液滴的铺展规律相同,正十六烷内边界前期铺展由重力主导,内边界铺展标度律在R～t~(1/4)到R～t~(1/2)范围.随后铺展由界面张力梯度主导,内边界铺展标度律为R～t~(3/4).因内边界铺展受重力影响,内边界的铺展速度与硅油体积成正相关.而正十六烷外边界在硅油驱动下,因接触角改变而产生界面张力梯度,在界面张力梯度作用下外边界铺展标度律为R～t~(3/4).

Surface tension gradient due to concentration difference and temperature difference induces liquid convection, known as Marangoni effect. The Marangoni effect has been extensively studied to understand its fundamental physics and its industrial applications. In this paper we study Marangoni effect of droplet in a three-phase liquid system. In this system, silicone oil is chosen as a driving liquid, and n-hexadecane is used as a driven liquid. A high-speed camera is used to capture the spreading process of n-hexadecane driven by silicon oil on the sodium dodecyl sulfate (SDS) solution. The experiment shows that n-hexadecane driven by silicone oil spreads from inside out, forming a ring structure. According to spreading dynamic behavior of internal boundary and external boundary of n-hexadecane ring, we study the spreading pattern of internal boundary and external boundary of n-hexadecane ring, and the influence of silicone oil volume on the spreading process. Analysis shows that the spreading law of internal silicone oil conforms to single droplet spreading at the liquid interface. In the initial spreading stage, the spreading of four-phase contact line (internal boundary) among silicone oil, air, n-hexadecane and water are dominated by gravity, The scale law of spreading distance R of four-phase contact line and t is in a range of R similar to t(1/4) - R similar to t(1/)(2). Owing to the gravity influence, the larger the volume of silicone oil, the faster the four-phase contact line spreads. The volume of silicone oil has no effect on the scaling law of the whole spreading process. The next spreading stage, the spreading of the contact line is dominated by the interfacial tension gradient. The scale law of spreading distance R and t conforms to R similar to t(3/4). Under silicone oil driven, the liquid thickness of n-hexadecane at the four-phase contact line (internal boundary) among air, silicone oil, N-hexadecane and water increases, thus changing the contact angle at three-phase contact line (external boundary) among air, n-hexadecane and water. The change of contact angle leads the interfacial tension gradient to produce. The interfacial tension gradient drives external boundary to spread. Because the spreading of the three-phase contact line is dominated by interfacial tension gradient, the scale law of spreading distance R of three-phase contact line and time t conforms to similar to t(3/4).