-
本文通过改变肋柱宽度和间距, 构造了二级和多级梯度微结构表面, 采用格子-Boltzmann方法对液滴在两种梯度表面上的铺展过程进行了研究, 探析液滴运动的机理和调控方法. 结果表明, 在改变肋柱间距的二级梯度表面上, 当液滴处于Cassie态时, 接触角滞后大小与粗糙度梯度成正比关系; 当液滴从Cassie态转换为Wenzel态或介于两者之间的不稳定态时, 这一正比关系不再遵循. 在改变肋柱宽度的二级梯度表面上, 接触角滞后大小与粗糙度梯度始终成正比关系. 在多级梯度表面上, 随液滴初始半径增大, 接触角滞后减小, 但液滴平衡位置相较于初始位置偏离增大. 对梯度微结构表面上液滴运动和接触角滞后的定量分析, 可为实现梯度微结构表面液滴运动调控提供理论依据.Designed microtextured surfaces have shown promising applications in tuning the wettability of a liquid droplet on the surfaces and attracted great attention over the past decade; unfortunately, the effect of surface geometry on wetting properties is still poorly understood. In this work, two- and multi-stage pillar microtextures are designed to construct gradient surfaces by altering pillar width and spacing. Then, the multi-phase lattice-Boltzmann method (LBM) is used to investigate the wetting dynamics of a liquid droplet on the gradient surface. Results show that for the two-stage gradient surface with variable pillar spacing, the contact angle hysteresis is found to be proportional to the roughness gradient when droplet/surface system is in the Cassie-Baxter state. However, this proportional relation is no longer correct when the system is in the transition state between the Wenzel and Cassie-Baxter states. For the two-stage gradient surface with variable pillar spacing, the contact angle hysteresis always increases linearly with increasing roughness gradient. Results also show that when a larger droplet is placed on the multi-stage gradient surface, stronger droplet motion is observed due to the smaller contact angle hysteresis. The present LBM simulations provide a guideline for the design and manufacture of the microtextured surfaces to tune the droplet wettability and motion.
-
Keywords:
- liquid droplet /
- micro-structural surface /
- spreading /
- contact angle
[1] de Gennes P G 1985 Rev. Mod. Phys. 57 827
[2] Liang Z P, Wang X D, Duan Y Y, Min Q 2012 Colloids Surf. A 403 155
[3] Martin C P, Blunt M O, Pauliac-Vaujour E, Stannard A, Moriarty P, Vancea I, Thiele U 2007 Phys. Rev. Lett. 99 116103
[4] Vancauwenberghe V, Marco P D, Brutin D 2013 Colloids Surf. A 432 50
[5] Pratap V, Moumen N, Subramanian R S 2008 Langmuir 24 5185
[6] Kakade B, Mehta R, Durge A, Kulkarni S, Pillai V 2008 Nano Lett. 8 2693
[7] Hong X, Gao X, Jiang L 2007 J. Am. Chem. Soc. 129 147
[8] Ichimura K, Oh S K, Nakagawa M 2000 Science 288 1624
[9] Lu G 2014 Ph. D. Dissertation (Beijing: Tsinghua University) (in Chinese) [陆规 2014 博士学位论文(北京: 清华大学)]
[10] Erbil H Y, Demirel A L, Avci Y, Mert O 2003 Science 299 1377
[11] Zu Y Q, Yan, Y Y, Li, J Q, Han Z W 2010 Journal of Bionic Engineering 7 191
[12] Raiskinmaki P, Kopenen A, Merikoski J, Timonen J 2000 Comput. Mater. Sci 18 7
[13] Lu G, Wang X D, Duan Y Y 2013 Colloids Surf. A 433 95
[14] Varnik F, Gross M, Moradi N, Zikos G, Uhlmann P, Mller-Buschbaum P, Magerl D, Raabe D, Steinbach I, Stamm M 2011 Journal of Physics: Condens. Matter 23 184112
[15] Li H B, Fang H P 2012 J. Adhes. Sci. Technol. 26 1873
[16] Wang X D, Peng X F, Wang B X 2004 Chin. J. Chem. Eng. 12 615
-
[1] de Gennes P G 1985 Rev. Mod. Phys. 57 827
[2] Liang Z P, Wang X D, Duan Y Y, Min Q 2012 Colloids Surf. A 403 155
[3] Martin C P, Blunt M O, Pauliac-Vaujour E, Stannard A, Moriarty P, Vancea I, Thiele U 2007 Phys. Rev. Lett. 99 116103
[4] Vancauwenberghe V, Marco P D, Brutin D 2013 Colloids Surf. A 432 50
[5] Pratap V, Moumen N, Subramanian R S 2008 Langmuir 24 5185
[6] Kakade B, Mehta R, Durge A, Kulkarni S, Pillai V 2008 Nano Lett. 8 2693
[7] Hong X, Gao X, Jiang L 2007 J. Am. Chem. Soc. 129 147
[8] Ichimura K, Oh S K, Nakagawa M 2000 Science 288 1624
[9] Lu G 2014 Ph. D. Dissertation (Beijing: Tsinghua University) (in Chinese) [陆规 2014 博士学位论文(北京: 清华大学)]
[10] Erbil H Y, Demirel A L, Avci Y, Mert O 2003 Science 299 1377
[11] Zu Y Q, Yan, Y Y, Li, J Q, Han Z W 2010 Journal of Bionic Engineering 7 191
[12] Raiskinmaki P, Kopenen A, Merikoski J, Timonen J 2000 Comput. Mater. Sci 18 7
[13] Lu G, Wang X D, Duan Y Y 2013 Colloids Surf. A 433 95
[14] Varnik F, Gross M, Moradi N, Zikos G, Uhlmann P, Mller-Buschbaum P, Magerl D, Raabe D, Steinbach I, Stamm M 2011 Journal of Physics: Condens. Matter 23 184112
[15] Li H B, Fang H P 2012 J. Adhes. Sci. Technol. 26 1873
[16] Wang X D, Peng X F, Wang B X 2004 Chin. J. Chem. Eng. 12 615
计量
- 文章访问数: 5029
- PDF下载量: 6410
- 被引次数: 0
下载:
