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滴外形法测定表面张力

滴外形法测定表面张力. 马晓明 00510101. Outline. Background&History Traditional Methods Development, Applications. Background&History. Manual Work. Drawbacks…. Demanding Photographs are prone to change, causing distortion Subjective factors…. Computer Work. Advantages…. Saving time & energy

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滴外形法测定表面张力

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  1. 滴外形法测定表面张力 马晓明 00510101

  2. Outline • Background&History • Traditional Methods • Development, Applications

  3. Background&History • Manual Work

  4. Drawbacks… • Demanding • Photographs are prone to change, causing distortion • Subjective factors…

  5. Computer Work

  6. Advantages… • Saving time & energy • Wider range (0.001mN/m~72mN/m) • All we need is g & Δρ • Reproducibility

  7. Traditional Methods • Principle (Bashforth-Adams Equation) • 停滴法 • 悬滴法

  8. b: O点曲率半径 R1：液面外形曲线在S点的曲率半径 R2：液面在垂直于纸面方向的曲率半径 x：AS z：OA

  9. 停滴法 • 外形比较法 实测vs标准外形曲线ß； 查表得x/b（φ=90°）； However!! 很难完全符合，要用非线性内插…… 我才发现梦想与现实间的差别

  10. 赤道参数法 赤道=x（φ=90°） • 实测（x，z）vsB-A表格数据（φ=90°） ； • 找出ß，推算b值； 扁平液滴误差大

  11. 等腰三角形法(Dorsey) • 描线-对轴-相切 （ φ=45°） • 略去1/b 肉眼看相切的误差……

  12. 注：书35页表内第一行0~9的数字代表S值的小数点后第三位数字注：书35页表内第一行0~9的数字代表S值的小数点后第三位数字

  13. Development • 轴称滴形分析(ADSA ,Axisymmetric Drop Shape Analysis) : Set up a new way to ‘express the error between the physically observed and a theoretical Laplacian curve’(2) • A lot of calculations…

  14. “建立一种新方法来表达物理实测拉普拉斯曲线与理想拉普拉斯曲线的误差”“建立一种新方法来表达物理实测拉普拉斯曲线与理想拉普拉斯曲线的误差” • 好多的计算……

  15. 轴称滴形直径法(ADSA-CD)(3)： ‘solving the Laplace equation (contact diameter, V, γ, Δρ and g)’ ‘manually selecting an arbitrary set of coordinates characterizing the perimeter of the sessile drop’

  16. “已知接触半径、表面张力、体积、密度差和重力加速度，求解拉普拉斯曲线方程”“已知接触半径、表面张力、体积、密度差和重力加速度，求解拉普拉斯曲线方程” • 由已知推算校正因子来应用于未知 • “人工选择一套任意坐标来描述固着滴的周长”

  17. Laser Scanning Drop Shape Analysis (LASDA) (1) ： Accuracy: 1~2μm Controllable process • 激光控制滴的生成、生长速度，高度平行的结果

  18. 悬滴界面张力仪（6）

  19. Applications • 测定表面压-面积曲线(优于LB膜天平） • 测定单分子膜的动态粘弹性(计算机控制的可控性运动）：单分子膜弹性E, 膜膨胀粘度K(5) • 在工业生产以及科研中快速准确地测定表面张力

  20. LB膜天平的缺点： • 试剂用量大 • 有机试剂易挥发 • 污染环境，同时样品易受污染 • 仅限于不溶性单分子膜 • E与表面压有关，K与单位时间内的表面张力差有关

  21. References • Semmler A, Ferstl R, Kohler HH. New Laser Technique for Automatic Interfacial Tension Measurements: Laser Scanning Drop Shape Analysis (LASDA).LANGMUIR, 1996, 20: 4165-4172 • Rotenberg Y, Boruvka L , Neumann A W. Determination of surface tension and contact angle from the shapes of axisymmetric fluid interfaces. J. Colloid Interface Sci., 1983, 93: 169-183 • Kazayawoko M, Neumann AW, Balatinecz JJ. Estimating the wettability of wood by the Axisymmetric Drop Shape Analysis Contact Diameter method. WOOD SCIENCE AND TECHNOLOGY , 1997, 31: 87-95 • 赵振国 等 界面化学基础 化学工业出版社 22-34

  22. 于军胜, 唐季安. 表（界）面张力测定方法的进展. 化学通报,1997，11, 11-15 • 李啸风, 陈志荣 等. 结合图像数字化技术用悬滴法测动态界面张力——动态界面张力与表面活性剂浓度的关系. 化工学报, 2001, 52(1), 545-548

  23. Review&Overlook • History • Methods • Development Tomorrow is Another Day

  24. Thanks！

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