Measuring the Strength of S/Se Based Dynamic Covalent Bonds

Jiahao Xia, Hongbin Li, Huaping Xu

Acta Polym. Sin., 2019, DOI: 10.11777/j.issn1000-3304.2019.19166

Sulfur, selenium-containing bonds, including disufide bond (SS), diselenide bond (SeSe) and selenide-sulfide bond (SeS), are an important type of light responsive dynamic covalent bonds. Among them SS and SeS bond can undergo exchange reaction with the irridiation of UV light while SeSe bond only requires visible light. In this paper we prepared SS or SeSe bond modified quartz substrate via surface modification. Based on the light induced exchange reaction we can obtain polymer chain attached substrates linked by a single bond of either SS, SeS or SeSe. Atomic Force Spectroscope based Single Molecule Force Spectroscopy (AFM-SMFS) measurement of three bonds indicated their strengths decrease as SS>SeS>SeSe. SMFS results illustrated that the strength of dynamic covalent bond is in betweeen that of non-covalent interaction and robust covalent bond (e.g. C-C bond), which accounts for its balance of responsiveness and stability.

Xia J 高分子学报 2019