讲座题目：From particle dynamics to droplet dynamics (Thermophoresis/wetting/ droplet impact/frosting/icing)

报告内容：

1. Collective effects on thermophoresis of colloids: a microfluidic study within the framework of DLVO theory；

2. Interdroplet freezing wave propagation of condensation frosting on micropillar patterned superhydrophobic surfaces；

3. Triple condensate halo from a single water droplet impacting upon a cold surface；

4. Freezing of a nanofluid droplet: from pointy tip to flat plateau；

讲座时间：2019年11月21日14:00

讲座地点：远航楼三区207

讲座摘要：Ice/snow accretions may cause severe consequences. Though various techniques of de-icing or anti-icing have been developed, more desirable approaches would be to hinder or prevent ice generation through changing surface structures or/and controlling icing processes. Here, we will report freezing of droplets from two different perspectives. First, we report retarded condensate freezing on micropillar patterned surfaces and examine the effects of pillar size and pitch as well as substrate wettability on freezing propagation velocity. Our experiments reveal three distinctive physical mechanisms/modes. An analytical model is proposed to describe the effects of wettability, morphology, and temperature on the frost spreading velocity. Second, we observed unique shape changes observed during the freezing process of nanofluid droplets. Instead of forming a pointy tip, the top of an ice droplet exhibits a flat plateau shape and such plateau is found to become larger with increasing particle concentration. We ascribe this characteristic shape change to an outward Marangoni flow which moves liquid from droplet interior to vertexes, thus engendering the volume redistribution and shape changes. We also found that the similar ring pattern occurs in freezing as in evaporation of nanofluid droplets.

报告人简介：

赵玉刚，上海理工大学特聘副教授，研究领域包括微纳米流体和电磁流体、液滴动力学、特殊浸润性表面、冷凝传热强化、结冰结霜。

教育经历：西安交通大学本科、中国工程物理研究院硕士、新加坡南洋理工博士。

科研成果：

论文发表在JCR一区文章数篇：

Y. Zhao,C. Zhao, J. He, Y. Zhou, and C. Yang, "Collective effects on thermophoresis of colloids: a microfluidic study within the framework of DLVO theory,"Soft Matter, vol. 9, pp. 7726-7734, 2013.

Y. Zhaoand C. Yang, "Retarded condensate freezing propagation on superhydrophobic surfaces patterned with micropillars,"Applied Physics Letters, vol. 108, p. 061605, Feb 8 2016.

Y. Zhao, R. Lin, T. Tran, and C. Yang, "Confined wetting of water on CNT web patterned surfaces,"Applied Physics Letters, vol. 111, p. 161604, Oct 16 2017.

Y. Zhao, R. Wang, and C. Yang, "Interdroplet freezing wave propagation of condensation frosting on micropillar patterned superhydrophobic surfaces of varying pitches,"International Journal of Heat and Mass Transfer, vol. 108, Part A, pp. 1048-1056, 5// 2017.

Y. Zhaoand C. Yang, "Frost spreading on microscale wettability/morphology patterned surfaces,"Applied Thermal Engineering, vol. 121, pp. 136-145, 7/5/ 2017.

Y. Zhao, H. Zhang, W. Wang, and C. Yang, "Wetting transition of sessile and condensate droplets on copper-based superhydrophobic surfaces,"International Journal of Heat and Mass Transfer, vol. 127, pp. 280-288, 2018/12/01/ 2018.

Y. Zhao, F. Zhu, H. Zhang, T. H. New, L. Jin, and C. Yang, "Triple condensate halo from a single water droplet impacting upon a cold surface,"Applied Physics Letters, vol. 114, p. 183703, 2019/05/06 2019.

其他SCI、Ei论文多篇。

项目包括：

上海市东方学者基金，2019-2021，60万，主持；

新加坡政府基金项目，2017.01-2020.01，518万，在研，参与；

新加坡政府基金项目，2015.11-2017.05，35万，结题，参与；

新加坡政府基金项目，2010.05-2013.08，470万，结题，参与。