Tribochemically Controlled Atom Transfer Radical Polymerization Enabled by Contact Electrification

Abstract

Traditional mechanochemically controlled reversible‐deactivation radical polymerization (RDRP) utilizes ultrasound or ball milling to regenerate activators, which induce side reactions because of the high‐energy and high‐frequency stimuli. Here, we propose a facile approach for tribochemically controlled atom transfer radical polymerization (tribo‐ATRP) that relies on contact‐electro‐catalysis (CEC) between titanium oxide (TiO2) particles and CuBr2/tris(2‐pyridylmethylamine (TPMA), without any high‐energy input. Under the friction induced by stirring, the TiO2 particles are electrified, continuously reducing CuBr2/TPMA into CuBr/TPMA, thereby conversing alkyl halides into active radicals to start ATRP. In addition, the effect of friction on the reaction was elucidated by theoretical simulation. The results indicated that increasing the frequency could reduce the energy barrier for the electron transfer from TiO2 particles to CuBr2/TPMA. In this study, the design of tribo‐ATRP was successfully achieved, enabling CEC (ca. 10 Hz) access to a variety of polymers with predetermined molecular weights, low dispersity, and high chain‐end fidelity.

A Mechanoredox Catalyst Facilitates ATRP of Vinylcyclopropanes

“…Even without ultrasound, the reaction still exhibits a monomer conversion of 25% (Table S1, entry 6). This phenomenon can be explained by the partial reduction of Cu­(II) due to the negative charge or the triboelectric effect of nanoparticles . When ZnO nanoparticles with a smaller BET specific surface area (7.9 m 2 /g) were used, the monomer conversion reached only 32% after 12 h (Table S1, entry 7).…”

“…Electron transfer from the surface of BaTiO 3 to the deactivator Cu II /L complex facilitated the formation of the activator Cu I /L complex. Since then, Matyjaszewski and others have further investigated the performance of BaTiO 3 and ZnO nanoparticles in order to enhance polymerization efficiency. − In addition, deep-penetration US in opaque media has also shown merit in biomedical applications. − Recently, we and others have explored mechanically controlled free radical polymerization, showcasing its potential for material remodeling. − …”

Enhanced Generation of Reactive Oxygen Species via Piezoelectrics based on p–n Heterojunctions with Built-In Electric Field

“…Piezocatalysis, as an emerging catalytic technology, offers a promising approach for inducing redox catalytic reactions through the use of piezoelectrics and ultrasound waves. − As a rule, the deformation of piezoelectrics triggered by ultrasound waves result in piezoelectric potentials on their surfaces, which can be used to initiate and accelerate chemical reactions . This approach offers distinct advantages, such as mild reaction conditions, improved reaction rates, and precise control over reaction kinetics. , In this context, piezocatalysis has shown significant potential in diverse applications, including organic synthesis, , water splitting, CO 2 reduction, , environmental remediation, − sonodynamics therapy, , etc.…”

Acid-Doped Pyridine-Based Polybenzimidazole as a Positive Triboelectric Material with Superior Charge Retention Capability

“…A triboelectric nanogenerator (TENG) is an extremely promising technology for energy conversion and self-powered sensor, while the intrinsic charge density of triboelectric materials is a key and unavoidable parameter for TENG applications. − To enhance the TENG output, external strategies such as a charge pumping/excitation strategy can be effective for energy-harvesting applications after an initial excitation process, − but this is not universally applicable and is inconvenient for other applications such as triboelectric catalysis and self-powered sensors. − Therefore, the development of the intrinsic charge density for triboelectric materials is fundamental and inevitable and can also help these strategies to achieve further enhancements. Previously, state-of-the-art strategies such as surface modification, , chemical design, repeated rheological modeling, and inorganic filler composites − have been proposed to elevate the charge density of negative materials.…”