Fluorinated Polymers via Para‐Fluoro‐Thiol and Thiol‐Bromo Click Step Growth Polymerization

• Published in: Macromolecular rapid communications. Vol. 41; no. 22; pp. e2000409 - n/a
• Main Authors: Zhao, Tieshuai, Beyer, Valentin P., Becer, Caglar Remzi
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.11.2020
• Subjects: Benzyl bromide; Calorimetry; Chemical reactions; Chemists; click reactions; Contact angle; Differential scanning calorimetry; Fluoropolymers; Glass transition temperature; Hydrophobicity; Monomers; multi‐block copolymers; para‐fluoro thiol reaction; Polymerization; Polymers; Stability analysis; Substitution reactions; Thermal properties; Thermal stability; Thermodynamic properties; Thermogravimetric analysis; Thiols; thiol‐bromo reaction; Transition temperatures
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.202000409

Click reactions are utilized widely to modify chain ends and side groups of polymers while click polymerizations based on step‐growth polymerization of bifunctional monomers have recently attracted increased attention of polymer chemists. Herein, the combination of two highly efficient click reactions, namely para‐fluoro‐thiol click and thiol‐bromo substitution reactions, is demonstrated to form fluorinated polymers with tuned hydrophobicity owing to the nature of the dithiol linker compound. The key compound in this study is 2,3,4,5,6‐pentafluoro benzyl bromide that provides the combination of thiol click reactions. The thiols used here are 4,4‐thiobisbenzenthiol, 2,2'‐(ethylenedioxy) diethanethiol, and 1,2‐ethanedithiol that allow tuning of the properties of obtained polymers. The step‐growth click reaction conditions are optimized by screening the effect of reaction temperature, base, solvent, and stochiometric ratio of the compounds. Thermal properties and hydrophobicity of synthesized polymers are determined via water contact angle, thermogravimetric analysis and differential scanning calorimetry measurements, showing thermal stability up to 300 °C, glass transition temperatures ranging from −25 to 82 °C and water contact angles ranging from 55 to 90 °C. A new method for the synthesis of a series of fluorinated polymers using commercially available dithiol compounds and 2,3,4,5,6‐pentafluoro benzyl bromides is reported. The step‐growth polymerization can proceed at room temperature while based on the nucleophilicity of dithiol compounds, the completion could be reached in 10 min. Obtained polymers have a good thermal resistance up to 300 °C and hydrophobic character is measured by water contact angle measurements.