Oxygen Tolerance in Surface-Initiated Reversible Deactivation Radical Polymerizations: Are Polymer Brushes Turning into Technology?

Abstract

Over the past three decades, the development of reversible deactivation radical polymerizations (RDRP), and advancements toward more user-friendly and accessible experimental setups have opened the door for nonexperts to design complex macromolecules with well-defined properties. External mediation, improved tolerance to oxygen, and increased reaction volumes for higher synthetic output are some of the many noteworthy technical improvements. The development of RDRPs in solution was paralleled by their application on solid substrates to synthesize surface-grafted “polymer brushes” via surface-initiated RDRP (SI-RDRP). This Viewpoint paper provides a current perspective on recent developments in SI-RDRP methods that are tolerant to oxygen, especially highlighting those that could potentially enable scaling up of the synthesis of brushes for the functionalization of technologically relevant materials.

Polycarbonate Surface Modification via Aqueous SI-PET-RAFT

“…WCA measurements were used to track polymer brush thickness changes on PC substrates, as the roughness and polymeric nature of the PC substrate made quantification by direct thickness measurement methods such as ellipsometry or AFM prohibitively challenging. Care was taken to avoid placing water droplets very close to the substrate edges due to potential drop deformation and the likely presence of edge effects, reported widely in the literature for oxygen-tolerant surface-initiated polymerizations. ,− Figure shows the evolution of WCA with polymerization time for pMETAC films grown from functionalized PC substrates. From initially θ PC,func.…”

Open-air green-light-driven ATRP enabled by dual photoredox/copper catalysis

“…To address these challenges, many efforts have been made to increase oxygen tolerance in ATRP. [14][15][16] Since, at the ATRP equilibrium, the concentration of Cu I /L is much higher than the concentration of propagating radicals, oxygen predominantly oxidizes Cu I /L rather than reacting with radicals. This inspired researchers to harness Cu I /Cu II catalysis to function also as an oxygen scavenger.…”

SI-PET-RAFT Polymerization via Electrodeposited Macroinitiator Thin Films: Toward Biomedical and Sensing Applications

“…The utility of PET-RAFT is practical for fabricating polymer brush thin films as it not only overcomes the abovementioned limitations of conventional SI-RAFT but is also ideal for preparing patterned polymeric surfaces. In the past few years, only a few studies on the use of surface-initiated PET-RAFT (SI-PET-RAFT) have been reported in the literature. − Li et alused SI-PET-RAFT to create polymer brush films with good oxygen tolerance and controllable patterned features. Seo et al developed an open-to-air SI-PET-RAFT polymerization approach to fabricating polymer brushes on silicon wafers under metal-free conditions.…”