纳米通道中毛细流动的实验研究

Experimental Study on the Capillary Filling in Nanochannels

本文实验研究了去离子水、乙醇、异丙醇以及质量分数分别为30%和70%的甘油水溶液在矩形截面纳米通道内的毛细流动过程,通道的深度分别为68 nm和116 nm。实验结果表明,流动距离l与时间t的1/2次方成正比(l∝t^1/2),且通道越深,流动速度越快,这与描述毛细流动过程的经典的Lucas-Washburn(LW)模型相符。但是,实验数据拟合斜率Aexp偏离理论预测值ALW,且(Aexp/ALW)与表征流体流动快慢的量(σcosθe/η)呈线性关系。根据发现的线性关系以及LW模型,本文提出了一个可以准确预测纳米通道中毛细流动动力学行为的新模型。

The capillary filling dynamics of deionized water,ethanol,isopropanol,30% and 70%(by weight)aqueous glycerol solutions in rectangular nanochannels with depths of 68 and 116 nm were studied experimentally.The experimental results show that the measured positionl is proportional to the square root of t(l∝t^1/2).The deeper the channel,the faster the filling speed,as predicted by the classical Lucas-Washburn(LW)model.However,the fitted slope Aexp deviates from the theoretical expectation ALW.The ratios(Aexp/ALW)are proportional to(σcosθe/η),where(σcosθe/η)is a factor that can characterize the speed of liquid.Based on the linearity correlation and LW model,we developed a modified LW model,which can accurately predict the capillary filling dynamics of various liquids in nanochannels.