The continuous amalgamation of photocatalysis into existing reversible deactivation radical polymerisation processes has initiated a rapidly propagating area of polymer research in recent years. We introduce bismuth oxide (Bi2O3) as a heterogeneous photocatalyst for polymerisations, operating at room temperature with visible light. We demonstrate formidable control over degenerative chain-transfer polymerisations, such as macromolecular design by interchange of xanthate (MADIX) and reversible addition-fragmentation chain transfer (RAFT) polymerisation. We achieved narrow molecular weight distributions and attribute the excellent temporal control to a photo-induced electron transfer (PET) process. This methodology was employed to synthesise diblock copolymers combining differently activated monomers. The Bi2O3 catalyst system has the additional benefits of low toxicity, reusability, low-cost, and ease of removal from the reaction mixture.

Surface-modified carbon nanotubes (CNTs) have become well-established filler materials for polymer nanocomposites. However, in immiscible polymer blends, the CNT-coating is selective toward the more compatible phase, which suppresses their homogeneous distribution and limits harnessing the full potential of the filler. In this study, we show that multiwalled CNTs with a patchy polystyrene/poly(methyl methacrylate) (PS/PMMA) corona disperse equally well in both phases of an incompatible PS/PMMA polymer blend. Unlike polymer-grafted CNTs with a uniform corona, the patchy CNTs are able to adjust their corona structure to the blend phases by selective swelling/collapse of respective miscible/immiscible surface patches. Importantly, the high interfacial activity of patchy CNTs further causes a significant decrease in PMMA droplet size with increasing filler content. The combined effect of compatibilization and homogeneous distribution makes patchy CNTs interesting materials for polymer blend nanocomposites, where next to the compatibilization, a homogeneous filler distribution is important to gain the desired materials property (e.g., reinforcement).

We pioneer the synthesis of well-defined high molar mass segmented copolymers, employing a unique combination of step-growth and reversible addition–fragmentation chain transfer (RAFT) polymerization. The step-growth precursor polymer is obtained via the ambient temperature UV-light-induced Diels–Alder reaction of 6′-(propane-1,3-diylbis­(oxy))­bis­(2-methyl­benzaldehyde) (AA monomer) and di­(isopropionic ethyl ester fumarate) trithio­carbonate (BB monomer). Unconventional off-stoichiometric conditions (r = [AA]0:[BB]0 = 1.5–1.75) are employed to ensure a sufficiently high incorporation of BB in the step-growth product (1200 ≤ M n/g mol–1 ≤ 3950). The optimum r value is based on a detailed product distribution analysis, comparing experimental and bivariate kinetic Monte Carlo generated data, using a scheme of over 200 reactions. The analysis highlights the unexpected occurrence of AA homopolymerization and the ligation of the resulting AA segments at higher reaction times. The precursor step-growth polymer is successfully transformed into a segmented copolymer via insertion of styrene by RAFT polymerization at 60 °C (11 200 ≤ M n/g mol–1 ≤ 53 400), as confirmed both experimentally and through simulations.

We introduce an inherently fluorescent self-reporting step-growth polymer system as well as a fluorescence-based methodology for accessing the kinetics of the underpinning photoinduced nitrile imine-mediated tetrazole-ene cycloaddition (NITEC) process, using an equimolar mixture of a bismaleimide linker and a bifunctional α,ω-tetrazole-chain transfer agent (CTA). Similarly, α,ω-tetrazole-capped polystyrene, prepared via RAFT polymerization, was employed as a photoreactive macromonomer. Upon UV irradiation, the tetrazole moiety readily reacts with activated dialkenes producing the fluorescent pyrazoline-containing polymer. Thus, the fluorescence emission of the step-growth polymers is directly correlated with the number of ligation points in the polymer, forming an ideal self-reporting sensor system. The viability of the fluorescence-based quantification is verified via NMR spectroscopy, evidencing that fluorescence-based polymerization monitoring is a viable avenue in cases where NMR spectroscopy is difficult to conduct.

The chemical structure and high aspect ratio of carbon nanotubes (CNTs) give rise to numerous exceptional physical properties but are also the origin for their intrinsic tendency to agglomerate. Since the full potential of CNTs is harnessed in homogeneous dispersions, e.g. in a polymer matrix, bundling of CNTs must be suppressed by compatibilizing unfavorable interfaces. We present a robust, noncovalent functionalization of multiwalled CNTs via physical grafting of polystyrene-block-polyethylene-block-poly(methyl methacrylate) (SEM) triblock terpolymers to the CNT surface in organic media. In an ultrasound-assisted approach at ambient temperature, the polyethylene (PE) middle block of SEM strongly adsorbs to the CNTs surface, yielding long-term stable dispersions of well-separated 1D hybrids with up to 3 wt % CNT content. Importantly, the strong affinity of PE toward CNTs prevents polymer desorption irrespective of the solvent conditions. The incompatible polystyrene (PS) and poly(methyl methacrylate) (PMMA) end blocks of SEM self-assemble into alternating PS/PMMA corona patches and provide excellent steric stabilization for the CNTs. Shorter PS and PMMA blocks give access to dispersions with higher CNT concentration and are more efficient in stabilizing longer CNTs. Unlike covalent functionalization methods, our approach preserves the conjugated sp 2 -structure of the CNTs and provides an efficient, simple and time-saving method for the preparation of polymer stabilized CNTs. The patchy PS/PMMA corona of the 1D hybrids is able to adapt to the surrounding environment as demonstrated on efficient high-content blending of PMMA with 5 wt % of welldispersed CNT/SEM hybrids.

We present a novel methodology to create rewritable surfaces using cysteine-rich domains via a combination of photolithography and reversible peptide-driven disulfide formation.

The use of labile covalent bonds such as oximes and acetals for their application in the synthesis, and controlled triggered deconstruction, of molecular polymer brushes (MPBs) is reported. Macromonomers (MMs) are produced via reversible addition‐fragmentation chain transfer (RAFT) polymerization using chain transfer agents (CTAs) featuring customized labile moieties. Ring‐opening metathesis polymerization (ROMP) of the MMs using the grafting‐through approach produced MPBs in which the cleavable CTA is incorporated along the backbone, between the brush mainchain and its side chains. Degradation (i.e., the detachment of side chains) of the brush is possible through exposure to an acid stimulus. Especially, ketoxime, solketal, and ethoxyethyl (EE) acetal‐based motifs demonstrate excellent orthogonality to the polymerization protocols. This study highlights how polymer architectures can be built from, and reverted to, single polymer chains by using well‐designed CTAs in a straight‐forward approach.

We introduce the facile synthesis of segmented copolymers by a catalyst-free Diels-Alder (DA) reaction at ambient temperature via step-growth and subsequent reversible addition fragmentation chain transfer (RAFT) polymerization. High molecular weight step-growth polymers are readily obtained (M = 40 000 g mol), featuring trithiocarbonate moieties in their chain, which allow monomer insertion via RAFT polymerization yielding high molecular weight species.