Feeling the Pressure: Effects of Formation Pressure on the Physical Properties of Titan Haze Analogs

Included are the dataset for Density, particle size, morphology, surface free energy, Young's modulus, and nanoindentation hardness obtained for tholin samples produced by the Southwest Research Institute's Tholinator setup from 2023 to 2025. Data are the following: Microscopy: HighPressureSEM.zip and LowPressureSEM.zip are compressed files of the scanning electron microscopy micrographs for high and low pressure samples, respectively. For each image included, there are three files: the original .tif image, the annotated .tif image used to obtain particle diameter using FIJI, and the .csv which contains the diameter and area of each particle counted for that particular image. All three files are labelled in the same way to associate them with each other, therefore all are named with the pressure, the sample creation date, and the micrograph number, and annotated .tif images contain the suffix -annotated to denote their annotated status (for example, HP240924_07.csv, HP240924_07.tif, and HP240924_07-annotated.csv). Nanoindentation: 20250825_SWRI5pcHP_FilmOnGlass_AllAreas.csv and 20250821_SWRI5pc_LP240710_20250821_AllAreas.csv are the .csv files for the nanoindentation results for the high-pressure and low-pressure sample, respectively. These files both contain the same 5 columns in this order: test number, hardness, modulus, standard deviation of hardness, and standard deviation of modulus. These data are continuous stiffness measurement data, presented already corrected for substrate influence following the method of Hay and Crawford 2011 (https://doi.org/10.1557/jmr.2011.8) Pycnometry: The following four files are pycnometry data for the high- and low-pressure samples: High Pressure: 240509_AH_HP_022224.csv; 240509_AH_HP41524.csv; 240603_AH_HP240522.csv Low Pressure: 240603_AH_LP52224.csv All files are organized with 7 columns: test number, initial pressure, final pressure, measured volume, temperature, and time in UTC-6. Below this data are the following rows: Sample mass in grams, the sample mass error, the average volume, the average volume standard deviation, the volume of the empty nano cell, the empty nano cell volume standard deviation, the resulting calculated sample volume (taken as average volume - empty nano cell volume), the sample volume error, and the density and density error calculate as sample mass / sample volume. Contact Angle: The following four files are the contact angle data used to calculate surface free energy, using diiodomethane and water as the test liquids: Low pressure: SwRI_LP_071024_diiodo_results.xlsx, SwRI_LP_071024_water_results.xlsx High pressure: SwRI_12HR_WaferSubstrate_water_results.xlsx, SwRI_12HR_WaferSubstrate_diiodo_results.xlsx Each excel workbook has a separate page for each test droplet dispensed, with the following columns: frame number, time elapsed from first frame, the left contact angle of the droplet, the right contact angle of the droplet, the average contact angle of the droplet, the RMSE of the left angle, the RMSE of the right angle, the pixel value of the left contact point, the pixel value of the right contact point, and the droplet width in pixels. Additionally, there is a results page for each workbook containing the following columns: the drop number, the average contact angle of the drop, the standard deviation of the drop angle $\sigma_i$, the number of frames included for each average, $\omega_i$ which is calculated as $\left(\frac{1}{\sigma_i}\right)^2$, and the average angle of all drops minus its ith component squared $(\theta_{avg}-\theta_i)^2$. Below these data is the final weighted average angle, the weighted error of the weighted average angle, the chi-squared of the angles, and the final error of the angle calculated using the weighted error and the chi squared (all relevant formulas are included in the .xlsx of each test liquid).