Chain-growth polymerizations are popular methods because they allow synthesis of high-molecular weight polymers in high yields and in short times. However, copolymers prepared by such processes generally exhibit uncontrolled monomer sequences. The controlled radical copolymerization of styrene with N-substituted maleimides is an interesting exception allowing preparation of controlled primary structures. However, because of the statistical nature of chain-growth mechanisms, sequence deviations are still present in these copolymers. Here we describe a specific range of experimental conditions that allows ultra-precise incorporation of a single N-substituted maleimide unit in a polystyrene chain. This occurs in a given kinetic regime where the styrene/N-substituted maleimide comonomer ratio is very low. This situation usually only arises in the later stages of a chain-growth polymerization. Nevertheless, we show that it is possible to restore these particular kinetic conditions multiple times during a single polymerization by using successive feeds of donor and acceptor comonomers.

The reversible addition-fragmentation chain transfer polymerization of 2-hydroxyethyl methacrylate (HEMA) from surfaces (S-RAFT) using an R-group-attached chain transfer agent (CTA) is presented. The approach was exploited for the efficient preparation of well-defined PHEMA brushes of up to 50 nm thickness in a controlled fashion without using any cytotoxic catalyst. The chemical composition, morphology and wettability of the samples were assessed by X-ray photoelectron spectroscopy, atomic force microscopy and water contact angle measurements, while the growth kinetics were studied by monitoring the dry thickness via spectroscopic ellipsometry. The mechanism and kinetics of the RAFT polymerization on the surfacein the presence of a sacrificial CTA and of solvent mixtures with different polaritieswere investigated. A marked effect of the concentration of the sacrificial CTA on the kinetics was observed. Importantlyand for the first timethe living PHEMA brushes were exploited as macroRAFT agents for chain extension, and thicknesses up to 70 nm were achieved. The prepared PHEMA brushes were challenged with protein solutions demonstrating their resistance to fouling.

The successful sequence-controlled installation of an activated ester using a newly designed monomer pentafluorophenyl 4-maleimidobenzoate is demonstrated. Pentafluorophenyl 4-maleimidobenzoate is kinetically installed at different stages of a nitroxide-mediated polymerization, namely, near the α-chain end and in the middle of a PS chain. In addition, successful installation of apolar and polar functional groups is achieved via post-polymerization functionalization, which demonstrated the versatility of the synthesis of a universal precursor for locally functionalized polymers.