flory_fox_scraper

Program with scripts to:

1. scrape information on glass transition temperatures of polymers - scrape_polyinfo.py, and
2. perform a Flory-Fox fit - fit_flory_fox.py.

Developed for case study in:

J.S. Peerless, N.J.B. Milliken, T.J. Oweida, M.D. Manning, Y.G. Yingling, Soft Matter Informatics: Current Progress and Challenges, Adv. Theory Simulations. 0 (2018) 1800129. doi:10.1002/adts.201800129.

Please cite paper above if used.

Author:
James S Peerless
Yingling Group
North Carolina State University

scrape_polyinfo.py

This script will scrape the NIMS PoLyInfo database for glass transition temperatures (Tg) and number-averaged molecular weights (Mn) reported for a single polymer in each polymer class. Script will identify a polymer in each polymer class with the most Tg data reported, then scan samples to extract Tg and Mn data. All data is then printed to a CSV file.

Inputs

A valid PoLyInfo login email and password is required. User will also be prompted for an output filename which will be the name of the output CSV file.

Outputs

Script will output status updates and timing info to stdout and a CSV file containing formatted information on data collected for each polymer targeted. CSV file includes:

• Polymer Class Name
• Polymer Class Abbreviation
• Full Polymer Name
• PoLyInfo Polymer Identification Number (PID)
• PoLyInfo Sample ID (SID)
• Scraped Glass Transition Temperature in K (Tg)
• Scraped Number-Averaged Molecular Weight in g/mol (Mn)

Notes

Test with wired 100 GB/s connection timed at 4h 10min. Bulk of this time is waiting for responses from PoLyInfo database.

fit_flory_fox.py

This script takes formatted CSV file from scrape_polyinfo.py and performs a ordinary least squares (OLS) fit of the Flory-Fox Equation to the data for each individual polymer class. Duplicate data and Tg and Mn points more than two standard deviations from mean are ignored.

Inputs

User will be asked to provide an input filename, which must be a CSV file of the format as produced by the scrape_polyinfo.py script above. User will also be asked for a output file prefix. This will determine the location and name for the output text file as well as the fit plots.

Outputs

Script will output a human-readable .txt file with information from each polymer in the input CSV file. Output for each polymer includes:

• Polymer Class Name
• Polymer Name
• PID
• Tg Max OLS Estimate in K
• Tg Max +/- 2 sigma Interval
• K OLS Estimate in K mol/g
• K +/- 2 sigma Interval
• Number of Data Points Used for OLS Fit
• Square Root of OLS Error Variance Estimate (sigma)
• OLS Covariance Matrix (V)

PNG file plotting fit, data, and residuals for each polymer class is saved to a dedicated directory.