SuFEx Postpolymerization Modification Kinetics and Reactivity in Polymer Brushes

Since its introduction in 2014, the sulfur(VI) fluoride exchange (SuFEx) reaction has emerged as a promising new reaction in the field of polymer chemistry, in both polymerization of diverse polymer backbones and postpolymerization modification (PPM). Previously, we successfully reported the use of SuFEx chemistry as a method for surface derivatization through the PPM of sulfonyl fluoride containing polymer brushes. However, with the diversity of conditions, substrate scope, and catalyst selection afforded by this reaction, it is advantageous to expand the use of SuFEx for PPM on polymer brushes to discern the advantages and limitations of this reaction in surface conjugation. In this work, we used three different polymer brush systems - alkyl sulfonyl fluorides, aromatic sulfonyl fluorides, and aromatic fluorosulfonates - and each was reacted with three different silyl ether derivatives (aryl, alkyl, and benzyl). Each of these reactions was subjected to different catalysts, and herein, we present rates, conditions, and side products for PPM of polymer brushes using SuFEx chemistry. In addition, we explored the use of TBDMS brushes and their reaction with fluorosulfonate derivatives, where surprisingly no surface reaction occurs. With these studies, we are able to better understand the rates and limitations of this click reaction in the context of surface derivatization.