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Dataset for: A Cross-Laboratory Comparison Study of Titan Haze Analogs: Surface Energy

Citation

Yu, Xinting; Li, Jialin (2021), Dataset for: A Cross-Laboratory Comparison Study of Titan Haze Analogs: Surface Energy, Dryad, Dataset, https://doi.org/10.7291/D13T16

Abstract

In Titan's nitrogen-methane atmosphere, photochemistry leads to the production of complex organic particles, forming Titan’s thick haze layers. Laboratory-produced aerosol analogs, or "tholins", are produced in a number of laboratories; however, most previous studies have investigated analogs produced by only one laboratory rather than a systematic, comparative analysis. In this study, we performed a comparative study of an important material property, the surface energy, of seven tholin samples produced in three independent laboratories under a broad range of experimental conditions, and explored their commonalities and differences. All seven tholin samples are found to have high surface energies, and are therefore highly cohesive. Thus, if the surface sediments on Titan are similar to tholins, future missions such as Dragonfly will likely encounter sticky sediments. We also identified a commonality between all the tholin samples: a high dispersive (non-polar) surface energy component of at least 30 mJ/m2. This common property could be shared by the actual haze particles on Titan as well. Given that the most abundant species interacting with the haze on Titan (methane, ethane, and nitrogen) are non-polar in nature, the dispersive surface energy component of the haze particles could be a determinant factor in condensate-haze and haze-lake liquids interactions on Titan. With this common trait of tholin samples, we confirmed the findings of a previous study by Yu et al. (2020) that haze particles are likely good cloud condensation nuclei (CCN) for methane and ethane clouds and would likely be completely wetted by the hydrocarbon lakes on Titan.

Methods

This dataset was collected by an Ossila goniometer and the contact angle data were extracted using ImageJ and the Ossila edge-detection software. The contact angle data were used for the surface energy measurement of the seven Titan haze analog samples described in the paper.

Usage Notes

The Excel file contains 15 tabs. The first provides the final reduced contact angle data for the 7 samples and their calculated surface energies (shown in Table 3 of the paper). In the next 14 tabs, the contact angle data for the 7 samples for both water and diiodomethane are provided. These tabs can be used to recreate Figure 3 of the paper.
 

Funding

Heising-Simons Foundation, Award: 51 Pegasi b Postdoc Fellowship