| Title: | Nanoscale-Agglomerate-Mediated Heterogeneous Nucleation |
| Author(s): | Cha H; Wu A; Kim MK; Saigusa K; Liu A; Miljkovic N; |
| Address: | "Department of Mechanical Science and Engineering, University of Illinois , Urbana, Illinois 61801, United States. International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University , 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan. Frederick Seitz Materials Research Laboratory, University of Illinois , Urbana, Illinois 61801, United States" |
| DOI: | 10.1021/acs.nanolett.7b03479 |
| ISSN/ISBN: | 1530-6992 (Electronic) 1530-6984 (Linking) |
| Abstract: | "Water vapor condensation on hydrophobic surfaces has received much attention due to its ability to rapidly shed water droplets and enhance heat transfer, anti-icing, water harvesting, energy harvesting, and self-cleaning performance. However, the mechanism of heterogeneous nucleation on hydrophobic surfaces remains poorly understood and is attributed to defects in the hydrophobic coating exposing the high surface energy substrate. Here, we observe the formation of high surface energy nanoscale agglomerates on hydrophobic coatings after condensation/evaporation cycles in ambient conditions. To investigate the deposition dynamics, we studied the nanoscale agglomerates as a function of condensation/evaporation cycles via optical and field emission scanning electron microscopy (FESEM), microgoniometric contact angle measurements, nucleation statistics, and energy dispersive X-ray spectroscopy (EDS). The FESEM and EDS results indicated that the nanoscale agglomerates stem from absorption of sulfuric acid based aerosol particles inside the droplet and adsorption of volatile organic compounds such as methanethiol (CH(3)SH), dimethyl disulfide (CH(3)SSCH), and dimethyl trisulfide (CH(3)SSSCH(3)) on the liquid-vapor interface during water vapor condensation, which act as preferential sites for heterogeneous nucleation after evaporation. The insights gained from this study elucidate fundamental aspects governing the behavior of both short- and long-term heterogeneous nucleation on hydrophobic surfaces, suggest previously unexplored microfabrication and air purification techniques, and present insights into the challenges facing the development of durable dropwise condensing surfaces" |
| Keywords: | Heterogeneous nucleation condensation durability hydrophobic nanoscale agglomerate volatile organic compounds; |
| Notes: | "PubMed-not-MEDLINECha, Hyeongyun Wu, Alex Kim, Moon-Kyung Saigusa, Kosuke Liu, Aihua Miljkovic, Nenad eng Research Support, Non-U.S. Gov't 2017/11/28 Nano Lett. 2017 Dec 13; 17(12):7544-7551. doi: 10.1021/acs.nanolett.7b03479. Epub 2017 Dec 1" |
