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针对含不溶性活性剂的垂直液膜排液过程,基于文献实验结果进一步完善了受活性剂浓度影响的分离压(disjoining pressure)模型,应用润滑理论建立了液膜厚度、活性剂浓度和液膜表面速度的演化方程组,通过数值计算分析了在不同分离压作用下含不溶性活性剂液膜的演化特征.结果表明,垂直液膜的排液过程通常经历两个阶段:首先是厚膜阶段,此时重力对排液过程起主导作用.在随后的薄膜阶段,毛细作用和分离压作用影响逐渐增大,其中分离压将控制液膜的演化历程.分离压对垂直液膜排液过程的影响与活性剂类型及活性剂浓度与静电作用力的关联强度密切相关.当分离压与活性剂浓度正相关时,随斥力关联系数α增大,液膜的排液和变薄过程得以减缓,由此增强了液膜稳定性;当分离压与活性剂浓度负相关时,随斥力关联系数α绝对值增大,液膜排液过程加速,由此加大液膜失稳的风险.For the drainage under the gravity of a vertical foam film containing insoluble surfactant, an improved concentration-dependent disjoining pressure model is formulated based on the published experimental results. The lubrication theory is used to establish the evolution equations of the film thickness, the surface concentration of insoluble surfactant, and the surface velocity, and the evolution characteristics of the film under different disjoining pressures are simulated numerically. The results show that the drainage process of a vertical liquid film generally undergoes two stages:the first stage is the thick film stage and the gravity plays a leading role in the drainage process; the subsequent stage is the thin film stage, the effects of capillary pressure and disjoining pressure increase gradually, and the disjoining pressure dominates the evolution of the film. The disjoining pressure effect is closely related to surfactant type and the correlation strength between the surfactant concentration and electrostatic repulsion force of disjoining pressure. For the ionic surfactant, electrostatic repulsion force increases with the increase of the surfactant concentration, but it is opposite for the nonionic surfactant. It is likely that the free hydroxide ions, which are considered to render the surface negatively charged, are partly adsorbed by the nonionic surfactant. So the surface charge of the foam film decreases as the concentration of the nonionic surfactant increases, resulting in a decrease in electrostatic repulsion. Therefore, some ionic surfactants can improve the stability of liquid film drainage and slow down the drainage process, while the effects of some nonionic surfactants are opposite. When the disjoining pressure is positively correlated with surfactant concentration, with the increase of correlation strength coefficient α, the thinning and drainaging processes of the film tend to slow down, hence the stability of the film is enhanced. When the disjoining pressure is negatively correlated with surfactant concentration, with the increase of the absolute value of α, the drainage process of the film is accelerated and the risk of film rupture is augmented. The results obtained in this paper are consistent with some of the experimental results, indicating that the concentration-dependent disjoining pressure is indeed an important factor in maintaining the stability of foam film containing some certain anionic or nonionic surfactants. The improved concentration-dependent disjoining pressure model established in this paper could not explain the phenomena of parts of cationic nor non-ionic surfactant film in drainage experiments. It can be inferred that the structure of surfactant molecule, the more detailed disjoining pressure model and the coupling of the disjoining pressure and surface elasticity should be considered in the future work.
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Keywords:
- vertical film /
- surfactant concentration /
- surfactant type /
- disjoining pressure
[1] Li G S 2013 Ph. D. Dissertation (Xuzhou:China University of Miningand Technology) (in Chinese)[李国胜2013博士学位论文] (徐州:中国矿业大学)
[2] Liang M Q, Yin H Y, Feng Y J 2016 Acta Phys. Chim. Sin. 32 2652(in Chinese)[梁梅清, 殷鸿尧, 冯玉军2016物理化学学报 32 2652]
[3] Wang J, Nguyen A V, Farrokhpay S 2016 Adv. Colloid Interfac. 228 55
[4] Du D X, Zhang N, Sun R, Wang C C, Zhang J, Li Y G 2016 CIESC J. 67 181(in Chinese)[杜东兴, 张娜, 孙芮, 王程程, 张健, 李莺歌2016化工学报 67 181]
[5] Mysels K J, Shinoda K, Frankel S 1959 Soap Films:Studies of Their Thinning and a Bibilography (New York:Pergammon) p116
[6] Bhakta A, Ruckenstein E 1997 Adv. Colloid Interfac. 70 1
[7] Tabakova S S, Danov K D 2009 J. Colloid Interface Sci. 336 273
[8] Manev E D, Pugh R J 1991 Langmuir 7 2253
[9] Carey E, Stubenrauch C 2010 J. Colloid Interface Sci. 343 314
[10] Schwartz L W, Roy R V 1999 J. Colloid Interface Sci. 218 309
[11] Naire S, Braun R J, Snow S A 2000 J. Colloid Interface Sci. 230 91
[12] Naire S, Braun R J, Snow S A 2001 Phys. Fluids 13 2492
[13] Braun R J, Snow S A, Naire S 2002 J. Eng. Math. 43 281
[14] Naire S, Braun R J, Snow S A 2004 J. Comput. Appl. Math. 166 385
[15] Sett S, Sinha-Ray S, Yarin A L 2013 Langmuir 29 4934
[16] Saulnier L, Champougny L, Bastien G, Restagno F, Langevin D, Rio E 2014 Soft Matter 10 2899
[17] Saulnier L, Boos J, Stubenrauch C, Rio E 2014 Soft Matter 10 7117
[18] De Wit A, Gallez D, Christov C I 1994 Phys. Fluids 6 3256
[19] Zhao Y P 2012 Physical Mechanics of Surface and Interface (Beijing:Science Press) pp185, 186(in Chinese)[赵亚溥2012表面与界面物理力学(北京:科学出版社)第185, 186页]
[20] Li C X, Pei J J, Ye X M 2013 Acta Phys. Sin. 62 214704(in Chinese)[李春曦, 裴建军, 叶学民2013 62 214704]
[21] Claesson P M, Kjellin M, Rojas O J, Stubenrauch C 2006 Phys. Chem. Chem. Phys. 8 5501
[22] Moulton D E, Lega J 2013 Eur. J. Appl. Math. 24 887
[23] Moulton D E, Lega J 2009 Physica D 238 2153
[24] Sakata E K, Berg J C 1972 J. Colloid Interface Sci. 40 99
[25] Ye X M, Jiang K, Li C X 2013 CIESC J. 64 3581(in Chinese)[叶学民, 姜凯, 李春曦2013化工学报 64 3581]
[26] Bergeron V 1997 Langmuir 13 3474
[27] Bykov A G, Lin S Y, Loglio G 2010 Colloids Surf. A:Physicochem. Eng. Asp. 354 382
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[1] Li G S 2013 Ph. D. Dissertation (Xuzhou:China University of Miningand Technology) (in Chinese)[李国胜2013博士学位论文] (徐州:中国矿业大学)
[2] Liang M Q, Yin H Y, Feng Y J 2016 Acta Phys. Chim. Sin. 32 2652(in Chinese)[梁梅清, 殷鸿尧, 冯玉军2016物理化学学报 32 2652]
[3] Wang J, Nguyen A V, Farrokhpay S 2016 Adv. Colloid Interfac. 228 55
[4] Du D X, Zhang N, Sun R, Wang C C, Zhang J, Li Y G 2016 CIESC J. 67 181(in Chinese)[杜东兴, 张娜, 孙芮, 王程程, 张健, 李莺歌2016化工学报 67 181]
[5] Mysels K J, Shinoda K, Frankel S 1959 Soap Films:Studies of Their Thinning and a Bibilography (New York:Pergammon) p116
[6] Bhakta A, Ruckenstein E 1997 Adv. Colloid Interfac. 70 1
[7] Tabakova S S, Danov K D 2009 J. Colloid Interface Sci. 336 273
[8] Manev E D, Pugh R J 1991 Langmuir 7 2253
[9] Carey E, Stubenrauch C 2010 J. Colloid Interface Sci. 343 314
[10] Schwartz L W, Roy R V 1999 J. Colloid Interface Sci. 218 309
[11] Naire S, Braun R J, Snow S A 2000 J. Colloid Interface Sci. 230 91
[12] Naire S, Braun R J, Snow S A 2001 Phys. Fluids 13 2492
[13] Braun R J, Snow S A, Naire S 2002 J. Eng. Math. 43 281
[14] Naire S, Braun R J, Snow S A 2004 J. Comput. Appl. Math. 166 385
[15] Sett S, Sinha-Ray S, Yarin A L 2013 Langmuir 29 4934
[16] Saulnier L, Champougny L, Bastien G, Restagno F, Langevin D, Rio E 2014 Soft Matter 10 2899
[17] Saulnier L, Boos J, Stubenrauch C, Rio E 2014 Soft Matter 10 7117
[18] De Wit A, Gallez D, Christov C I 1994 Phys. Fluids 6 3256
[19] Zhao Y P 2012 Physical Mechanics of Surface and Interface (Beijing:Science Press) pp185, 186(in Chinese)[赵亚溥2012表面与界面物理力学(北京:科学出版社)第185, 186页]
[20] Li C X, Pei J J, Ye X M 2013 Acta Phys. Sin. 62 214704(in Chinese)[李春曦, 裴建军, 叶学民2013 62 214704]
[21] Claesson P M, Kjellin M, Rojas O J, Stubenrauch C 2006 Phys. Chem. Chem. Phys. 8 5501
[22] Moulton D E, Lega J 2013 Eur. J. Appl. Math. 24 887
[23] Moulton D E, Lega J 2009 Physica D 238 2153
[24] Sakata E K, Berg J C 1972 J. Colloid Interface Sci. 40 99
[25] Ye X M, Jiang K, Li C X 2013 CIESC J. 64 3581(in Chinese)[叶学民, 姜凯, 李春曦2013化工学报 64 3581]
[26] Bergeron V 1997 Langmuir 13 3474
[27] Bykov A G, Lin S Y, Loglio G 2010 Colloids Surf. A:Physicochem. Eng. Asp. 354 382
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