Reversible Complexation Mediated Polymerization Research Articles

Reversible complexation mediated polymerization (RCMP) starting with a complex of iodine with organic salt and thermal initiators

Reversible complexation mediated polymerization (RCMP) starting with a complex of iodine with organic salt and thermal initiators

Preparation of Block Copolymer Self-Assemblies via Pisa in a Non-Polar Medium Based on RCMP.

Polymerization-induced self-assembly (PISA) is conducted in a non-polar medium (n-dodecane) via reversible complexation-mediated polymerization (RCMP). Stearyl methacrylate (SMA) is used to synthesize a macroinitiator, and subsequent block polymerization of benzyl methacrylate (BzMA) from the macroinitiator in n-dodecane afforded a PSMA-PBzMA block copolymer, where PSMA is poly(stearyl methacrylate) and PBzMA is poly(benzyl methacrylate). Because PSMA is soluble but PBzMA is insoluble in n-dodecane, the block copolymer formed a self-assembly during the block polymerization (PISA). Spherical micelles, worms, and vesicles are obtained, depending on the degrees of polymerization of PSMA and PBzMA. "One-pot" PISA is also attained; namely, BzMA is directly added to the reaction mixture of the macroinitiator synthesis, and PISA is conducted in the same pot without purification of the macroinitiator. The spherical micelle and vesicle structures are also fixed using a crosslinkable monomer during PISA. RCMP-PISA is highly attractive as it is odorless and metal-free. The "one-pot" synthesis does not require the purification of the macroinitiator. RCMP-PISA can provide a practical approach to synthesize self-assemblies in non-polar media.

Two‐dimensional β‐ketoenamine linked azo covalent organic frameworks as heterogeneous catalysts for photo‐induced RCMP

AbstractPhoto‐induced reversible complexation‐mediated polymerization (RCMP) is a green and economical method to prepare polymers with precise molecular weights, narrow molecular weight distributions and functionally active chain ends. Covalent organic frameworks (COFs) are a promising heterogeneous photocatalyst for mediating RCMP due to their adjustable structure, band gap, and porosity. In this work, 1,3,5‐triformylphloroglucinol (Tp) and p‐azoaniline (Azo) were selected to construct 2D β‐ketoenamine linked Tp‐Azo‐COF as a heterogeneous photocatalyst to trigger RCMP under white light irradiation. A series of polymers with controllable molecular weight and narrow molecular weight distribution were successfully prepared by using Tp‐Azo‐COF as photocatalysis. On/off light experiments confirmed the good spatiotemporal control feature, and chain expansion experiments demonstrated the high “activity” of polymer chain ends. Furthermore, the mechanistic research elucidated that electron transfer between Tp‐Azo‐COF and initiator occurred, allowing the formation of reactive radicals to mediate RCMP. Density functional theory calculations revealed that the coordination of iodine on the initiator to catalyst obviously reduced the bond dissociation energy, leading to enhance in the polymerization rate. This work provides a platform for constructing heterogeneous photocatalysts with more efficient and stable to mediate RCMP.

One‐Pot Reversible Complexation‐Mediated Polymerization (RCMP) from Benzylic Alcohols for Facile Access to Polymer‐Grafted Lignin

AbstractOne‐pot synthesis of methacrylic and acrylic polymers from benzylic alcohols (R−OH) used as initiating moieties was developed. R−OH was converted to alkyl iodide (R−I), and the generated R−I was used as an initiator without purification or isolation in the subsequent reversible complexation mediated polymerization (RCMP), leading to one‐pot RCMP from R−OH. As a useful application, this technique was exploited for one‐pot polymer‐grafting from lignin that is the second most abundant renewable carbon‐source on earth and bears benzylic alcohols. The direct initiation from lignin eliminates tedious initiator attachment and purification, offering a facile access to polymer‐grafted lignin. The obtained polymer‐grafted lignin was utilized to form an efficient UV‐absorbing film with high transparency in visible region. One‐pot RCMP may serve as a practical method to obtain value‐added functional lignin‐polymer composites.

One-Pot Reversible Complexation-Mediated Polymerization (RCMP) from Benzylic Alcohols for Facile Access to Polymer-Grafted Lignin.

One-pot synthesis of methacrylic and acrylic polymers from benzylic alcohols (R-OH) used as initiating moieties was developed. R-OH was converted to alkyl iodide (R-I), and the generated R-I was used as an initiator without purification or isolation in the subsequent reversible complexation mediated polymerization (RCMP), leading to one-pot RCMP from R-OH. As a useful application, this technique was exploited for one-pot polymer-grafting from lignin that is the second most abundant renewable carbon-source on earth and bears benzylic alcohols. The direct initiation from lignin eliminates tedious initiator attachment and purification, offering a facile access to polymer-grafted lignin. The obtained polymer-grafted lignin was utilized to form an efficient UV-absorbing film with high transparency in visible region. One-pot RCMP may serve as a practical method to obtain value-added functional lignin-polymer composites.

Novel Chain-End Modification of Polymer Iodides via Reversible Complexation-Mediated Polymerization with Functionalized Radical Generation Agents.

The modification of polymer chain ends is important in order to produce highly functional polymers. A novel chain-end modification of polymer iodides (Polymer-I) via reversible complexation-mediated polymerization (RCMP) with different functionalized radical generation agents, such as azo compounds and organic peroxides, was developed. This reaction was comprehensively studied for three different polymers, i.e., poly (methyl methacrylate), polystyrene and poly (n-butyl acrylate) (PBA), two different functional azo compounds with aliphatic alkyl and carboxy groups, three different functional diacyl peroxides with aliphatic alkyl, aromatic, and carboxy groups, and one peroxydicarbonate with an aliphatic alkyl group. The reaction mechanism was probed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The combination of PBA-I, iodine abstraction catalyst and different functional diacyl peroxides enabled higher chain-end modification to desired moieties from the diacyl peroxide. The dominant key factors for efficiency in this chain-end modification mechanism were the combination rate constant and the amount of radicals generated per unit of time.

Synthesis of PDMS/PEG graft-like and block copolymers via industrially relevant reverse iodine transfer polymerization

Advanced polymer structures are gaining traction in the coatings industry where they may, for instance, give rise to antifouling and anti-icing surfaces. With a focus on industrial feasibility, a series of copolymers from poly(dimethylsiloxane) monomethacrylate (PDMSMA), methoxy poly(ethylene glycol) monomethacrylate (MPEGMA) and methyl methacrylate (MMA) were prepared via reverse iodine transfer polymerization (RITP) and reversible complexation mediated polymerization (RCMP). Using inexpensive materials and synthesis approaches scalable for larger industrial quantities, a variety of (amphiphilic) copolymers and block copolymers were prepared. Compared to semi-batch free-radical polymerization (FRP), the RITP/RCMP approaches resulted in higher conversions of the macromonomers, lower polymer dispersities, allowed synthesis of block copolymers, as well as being simpler than most other common RDRP techniques.

Air-Tolerant Reversible Complexation Mediated Polymerization (RCMP) Using Aldehyde.

An air-tolerant reversible complexation mediated polymerization (RCMP) technique, which can be carried out without prior deoxygenation, is developed. The system contains a monomer, an alkyl iodide initiating dormant species, air (oxygen), an aldehyde, N-hydroxyphthalimide (NHPI), and a base. Oxygen is consumed via the NHPI-catalyzed conversion of the aldehyde (RCHO) to a carboxylic acid (RCOOH). The generated RCOOH is further converted to a carboxylate anion (RCOO- ) by the base. The RCOO- generated in situ works as an RCMP catalyst; the polymerization proceeds with the monomer, alkyl iodide dormant species, and RCOO- catalyst. Thus, the system is not only air-tolerant but also does not require additional RCMP catalysts, which is a notable feature of this system. (NHPI is used as an oxidation catalyst for converting RCHO to RCOOH.) This technique is amenable to methyl methacrylate, butyl methacrylate, benzyl methacrylate, 2-hydroxyethyl methacrylate, and styrene, yielding polymers with relatively low-dispersity (Mw /Mn =1.20-1.49), where Mw and Mn are the weight- and number-average molecular weights, respectively.

Reversible complexation mediated polymerization: an emerging type of organocatalytically controlled radical polymerization

Reversible complexation mediated polymerization (RCMP) was developed as a new class of controlled radical polymerization (CRP) using organic catalysts. In particular, photo-RCMP is among the simplest, cheapest, and most robust photoinduced CRPs.

Aqueous emulsion polymerizations of methacrylates and styrene via reversible complexation mediated polymerization (RCMP)

Aqueous emulsion polymerization via reversible complexation mediated living radical polymerization yielded low-dispersity poly(methyl methacrylate)s and polystyrenes.

Hybrid Polymerization of Reversible Complexation Mediated Polymerization (RCMP) and Reversible Addition–Fragmentation Chain-Transfer (RAFT) Polymerization

Hybrid polymerization of reversible complexation mediated polymerization (RCMP) and reversible addition–fragmentation chain-transfer (RAFT) polymerization was designed via introducing the chain-tra...

Dual roles of 4-N,N-dimethylaminostyrene as both catalyst and monomer in reversible complexation mediated polymerization for the synthesis of functional polystyrene and polystyrene-block-polyisoprene-block-polystyrene

A styrene derivative, 4-N,N-dimethylaminostyrene (MAS), serving as both catalyst and monomer was exploited in reversible complexation mediated polymerization (RCMP). Radical trap experiment and UV–vis spectroscopy analysis revealed that MAS as a catalyst could abstract iodine from iodine-containing compound to generate propagating radical species. Kinetic studies demonstrated that the polymerization of styrene in the presence of MAS proceeded in a “living”/controlled manner, affording polymers with controlled molecular weights and narrow molecular weight distributions. The livingness of the obtained polymer was confirmed by chain extension. Determined by water contact angle measurement, incorporation of MAS into the polymer led to the enhancement of surface energy. Moreover, using α,ω-bis(2-iodo-2-phenylacetoxy)-end functionalized cis-1,4-polyisoprene as a macroinitiator which was synthesized through cross-metathesis of cis-1,4-polyisoprene with cis-1, 4-bis(2-iodo-2-phenylacetoxy)-2-butene, the polymerization of styrene in the presence of MAS also exhibited typical features of “living”/controlled radical polymerization to yield polystyrene-block-polyisoprene-block-polystyrene.

Highly Branched Copolymers with Degradable Bridges for Antifouling Coatings.

The antifouling properties of traditional self-polishing marine antifouling coatings are mainly achieved based on their hydrolysis-sensitive side groups or the degradable polymer main chains. Here, we prepared a highly branched copolymer for self-polishing antifouling coatings, in which the primary polymer chains are bridged by degradable fragments (poly-ε-caprolactone, PCL). Owing to the partial or complete degradation of PCL fragments, the remaining coating on the surface can be broken down and eroded by seawater. Finally, the polymeric surface is self-polished and self-renewed. The designed highly branched copolymers were successfully prepared by reversible complexation mediated polymerization (RCMP), and their primary main chains had an Mn of approximately 3410 g·mol-1. The hydrolytic degradation results showed that the degradation of the copolymer was controlled, and the degradation rate increased with increasing contents of degradable fragments. The algae settlement assay tests indicated that the copolymer itself has some antibiofouling ability. Moreover, the copolymer can serve as a controlled release matrix for antifoulant 4,5-dichloro-2-octylisothiazolone (DCOIT), and the release rate increases with the contents of degradable fragments. The marine field tests confirmed that these copolymer-based coatings exhibited excellent antibiofouling ability for more than 3 months. The current copolymer is derived from commonly used monomers and an easily conducted polymerization method. Hence, we believe this method may offer innovative insights into marine antifouling applications.

Recent development in halogen-bonding-catalyzed living radical polymerization

The development and applications of an organocatalyzed living radical polymerization via halogen-bonding catalysis, i.e., reversible complexation mediated polymerization (RCMP), are highlighted.

Reversible complexation mediated polymerization (RCMP)–solution polymerization of methyl methacrylate catalyzed by Bu4N+I− (BNI) with in-situ formed alkyl iodide initiator

ABSTRACTThe reversible complexation mediated polymerization (RCMP) of methyl methacrylate catalyzed by tetrabutylammonium iodide (BNI) was performed in toluene with an alkyl iodide initiator in situ formed. The influence of BNI amount, polymerization temperature, solvent, and initiator on the polymerization was studied. Results showed that the more organic catalyst, higher reaction temperature, highly polar solvent, and higher activity initiator led to shorter inhibition period and faster polymerization. More importantly, the mechanism for the shorter inhibition period and faster polymerization with BNI was proposed:Poly(methyl methacrylate) with predetermined molar mass and relatively low Mw/Mn (determined by size exclusion chromatography, SEC) was successfully synthesized. Furthermore, the structure of resulting polymers was characterized using 1H NMR The living/controlled feature of the polymers was further demonstrated by the chain extension experiment. Attractive features of this procedure include commercially available catalyst, ease of operation, and efficiency.

Synthesis of transition-metal-free and sulfur-free nanoparticles and nanocapsules via reversible complexation mediated polymerization (RCMP) and polymerization induced self-assembly (PISA)

Transition-metal-free and sulfur-free synthesis of spheres, worms, and vesicles via the combination of organocatalyzed living radical polymerization and PISA.

Self-condensing reversible complexation-mediated copolymerization for highly branched polymers with in situ formed inimers

In this work, reversible complexation-mediated polymerization (RCMP) was modified to suit self-condensing vinyl polymerization (SCVP) aimed at the synthesis of highly branched polymers.

Theoretical and Experimental Studies on Elementary Reactions in Living Radical Polymerization via Organic Amine Catalysis

The reaction mechanism of living radical polymerization using organic catalysts, a reversible complexation mediated polymerization (RCMP), was studied using both theoretical calculations and experiments. The studied catalysts are tetramethylguanidine (TMG), triethylamine (TEA), and thiophene. Methyl 2-iodoisobutyrate (MMA-I) was used as the low-molar-mass model of the dormant species (alkyl iodide) of poly(methyl methacrylate) iodide (PMMA-I). For the reaction of MMA-I with TEA to generate MMA• and •I-TEA radicals (activation process), the Gibbs activation free energy for the inner-sphere electron transfer mechanism was calculated to be 39.7 kcal mol–1, while the observed one was 25.1 kcal mol–1. This difference of the energies suggests that the present RCMP proceeds via the outer-sphere electron transfer mechanism, i.e., single-electron transfer (SET) reaction from TEA to MMA-I to generate MMA• and •I-TEA radicals. The mechanism of the deactivation process of MMA• to generate MMA-I was also theoretically studied. For the studied three catalysts, the theoretical results reasonably elucidated the experimentally observed polymerization behaviors.

Organic Catalysts for Photocontrolled Polymerizations

Photocontrolled polymerization is an emerging field of study in which catalysis with organic-based dyes has enabled the practical and inexpensive synthesis of well-defined, spatially and temporally controlled polymeric structures. Herein, we review the current progress in the development of organic catalysts for photoregulated polymerizations. In particular, we highlight advances in metal-free variants of photomediated controlled radical polymerizations. In addition, we examine how the unique properties of these catalysts allow the development of two mechanistically distinct chain-growth polymerizations controlled by light. 1 Introduction 2 Photocontrolled Atom-Transfer Radical Polymerization (ATRP) 3 Photocontrolled Reversible Addition–Fragmentation Chain Transfer (RAFT) 4 Reversible Complexation-Mediated Polymerization (RCMP) 5 Photocontrolled Ring-Opening Metathesis Polymerization (ROMP) 6 Conclusion and Future Outlook

PMDETA as an efficient catalyst for bulk reversible complexation mediated polymerization (RCMP) in the absence of additional metal salts and deoxygenation

PMDETA was used as a commercial and efficient catalyst for reversible complexation mediated polymerization (RCMP) without deoxygenation in bulk, which could potentially allow the more facile preparation, post-treatment and storage.