Controlled Radical Polymerization Research Articles

Fluorescence Sensing of Eclampsia Biomarkers via the Immunosorbent Atom Transfer Radical Polymerization Assay.

Accurate and quantitative detection of pre-eclampsia markers is crucial in reducing pregnancy mortality rates. This study introduces a novel approach utilizing a fluorescent biosensor by the immunosorbent atom transfer radical polymerization (immuno-ATRP) assay to detect the pre-eclampsia protein marker CD81. The critical step used in this sensor is the novel signal amplification strategy of fluorescein polymerization mediated by ferritin-enhanced controlled radical polymerization, which combines with a traditional enzyme-linked immunosorbent assay (ELISA) to further reduce the detection limit of the CD81 protein concentration. The fluorescence intensity was linear versus logarithmic CD81 protein concentration from 0.1 to 10,000 pg mL-1, and the detection limit was 0.067 pg mL-1. Surprisingly, in 30% normal human serum (NHS), the sensor can also detect target protein over 0.1-10,000 pg mL-1, with 0.083 pg mL-1 for the detection limit. Moreover, the proposed biosensor is designed to be cost-effective, making it accessible, particularly in resource-limited settings where expensive detection techniques may not be available. The affordability of this method enables widespread screening and monitoring of preeclampsia, ultimately benefiting many pregnant women by improving their healthcare outcomes. In short, developing of a low-cost and susceptible direct detection method for preeclampsia protein markers, such as CD81, through the use of the immuno-ATRP assay, has significant implications for reducing pregnancy mortality. This method holds promise for early detection, precise treatment, and improved management of preeclampsia, thereby contributing to better maternal and fetal health.

Synthesis and Reactivity of Diazirine-Containing Polymers via Controlled Radical Polymerization

Synthesis and Reactivity of Diazirine-Containing Polymers via Controlled Radical Polymerization

Mechanically triggered on-demand degradation of polymers synthesized by radical polymerizations.

Polymers that degrade on demand have the potential to facilitate chemical recycling, reduce environmental pollution and are useful in implant immolation, drug delivery or as adhesives that debond on demand. However, polymers made by radical polymerization, which feature all carbon-bond backbones and constitute the most important class of polymers, have proven difficult to render degradable. Here we report cyclobutene-based monomers that can be co-polymerized with conventional monomers and impart the resulting polymers with mechanically triggered degradability. The cyclobutene residues act as mechanophores and can undergo a mechanically triggered ring-opening reaction, which causes a rearrangement that renders the polymer chains cleavable by hydrolysis under basic conditions. These cyclobutene-based monomers are broadly applicable in free radical and controlled radical polymerizations, introduce functional groups into the backbone of polymers and allow the mechanically gated degradation of high-molecular-weight materials or cross-linked polymer networks into low-molecular-weight species.

Ternary nanocomposite of RAFT‐polymerized DMAEMA‐functionalized graphene oxide, manganese dioxide and polyaniline as active electrode material for supercapacitor

AbstractGraphene and its derivatives are promising energy storage devices due to their high specific surface area, chemical and thermal durability and high charge transfer power. Still, their stacking and aggregate behavior can limit their practical application. To address this issue, reversible addition–fragmentation chain‐transfer (RAFT) polymerization as controlled radical polymerization was applied to functionalize the surface of graphene oxide with poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) via the ‘grafting from’ method. This strategy enhances the distance between graphene sheets by occupying physical volume while improving effective charge transfer through tertiary amine groups participating in the doping process. X‐ray diffraction was used to determine interlayer spacing after polymer grafting, which increased from 0.28 to 1.71 nm after polymer grafting. The hybridization of materials with diverse properties was used to enhance charge transfer capability for supercapacitor applications. PDMAEMA‐functionalized graphene oxide, nano‐manganese dioxide and polyaniline were combined to create a successful nanocomposite as electrode active material. The morphological structure and chemical composition of the synthesized nanocomposite were analyzed, and its electrochemical performance was evaluated using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The nanocomposite exhibited a maximum specific capacitance, energy density and power density of 364.72 F g−1 (at a scan rate of 50 mV s−1), 239.08 Wh kg−1 and 678.34 W kg−1, respectively. The final nanocomposite's energy storage capacity significantly increased compared to the individual components due to hybridization's synergistic impact, reducing charge transfer resistance. © 2024 Society of Industrial Chemistry.

Design of functional soft interfaces with precise control of the polymer architecture

AbstractSoft interfaces formed by polymer materials are important interfaces for biological systems (biointerfaces), and controlling their chemical and physical structures at the nanoscale plays an important role in understanding the mechanism and development of interface functionalities. Controlled radical polymerization (CRP) is highly suited for designing biointerfaces composed of polymer chains because it enables the formation of well-defined polymer brushes, block copolymers, and comb-type copolymers. This focus review describes the design of functional soft interfaces based on investigations of the structure-property relationships of CRPs. In particular, polymer brush surfaces showing autonomous property changes, 2D/3D transformations of lipid bilayers, and molecular interactions in bactericidal cationic polymer brushes are depicted.

Hybrid Photoiniferter and Ring-Opening Polymerization Yields One-Pot Anisotropic Nanorods.

Polymerization-induced self-assembly (PISA) has emerged as a scalable one-pot technique to prepare block copolymer nanoparticles. Recently, we developed a PISA process that resulted in poly(L-lactide)-b-poly(ethylene glycol) block copolymer nanoparticles coined ring-opening polymerization-induced crystallization-driven self-assembly (ROPI-CDSA). The resulting nanorods demonstrated a strong propensity for aggregation, resulting in the formation of 2D sheets and 3D networks. Here, we report the synthesis of poly(N,N-dimethyl acrylamide)-b-poly(L)-lactide block copolymer nanoparticles by ROPI-CDSA utilizing a two-step, one-pot approach. A dual-functionalized photoiniferter was first used for controlled radical polymerization of the acrylamido-based monomer, and the resulting polymer served as a macroinitiator for organocatalyzed ring-opening polymerization to form the solvophobic polyester block. The resulting nanorods are highly stable and display anisotropy at higher molecular weights (>12k Da) and concentrations (>20% solids) than our previous report. This development expands the chemical scope of ROPI-CDSA block copolymers and provides readily accessible nanorods made with biocompatible materials. This article is protected by copyright. All rights reserved.

Nitroxide-Mediated Controlled Radical Copolymerization of α-Trifluoromethylstyrenes with Styrenes.

Fluorinated polymers are important materials in everyday life; however, most monomers of widely used fluoropolymers are gaseous, and their polymerization is difficult in an ordinary laboratory. Therefore, partially fluorinated polymers have recently been reported. As an easy-to-handle fluorine-containing monomer, α-trifluoromethylstyrene (TFMST) can be used to produce partially fluorinated polymers with trifluoromethyl groups in the main chain; however, TFMST does not homopolymerize, and there are limited reports on its copolymerization with styrene (ST). In this study, we applied the controlled radical polymerization method, which is effective for the polymerization of ST, to the copolymerization of TFMST and ST. We also showed that nitroxide-mediated polymerization is effective. The content ratio of TFMST in the TFMST-ST copolymer can be controlled between 10% and 40% by changing its monomer ratio. Additionally, the polymerization of TFMST and ST with substituents was performed to increase structural variations. The thermal stability as well as water and oil repellency of the synthesized polymers with different composition ratios and substituents were also evaluated.

Postpolymerization Modification of Poly(2-vinyl-4,4-dimethyl azlactone) as a Versatile Strategy for Drug Conjugation and Stimuli-Responsive Release.

Postpolymerization modification of highly defined "scaffold" polymers is a promising approach for overcoming the existing limitations of controlled radical polymerization such as batch-to-batch inconsistencies, accessibility to different monomers, and compatibility with harsh synthesis conditions. Using multiple physicochemical characterization techniques, we demonstrate that poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) scaffolds can be efficiently modified with a coumarin derivative, doxorubicin, and camptothecin small molecule drugs. Subsequently, we show that coumarin-modified PVDMA has a high cellular biocompatibility and that coumarin derivatives are liberated from the polymer in the intracellular environment for cytosolic accumulation. In addition, we report the pharmacokinetics, biodistribution, and antitumor efficacy of a PVDMA-based polymer for the first time, demonstrating unique accumulation patterns based on the administration route (i.e., intravenous vs oral), efficient tumor uptake, and tumor growth inhibition in 4T1 orthotopic triple negative breast cancer (TNBC) xenografts. This work establishes the utility of PVDMA as a versatile chemical platform for producing polymer-drug conjugates with a tunable, stimuli-responsive delivery.

Surface Functionalization with Polymer Brushes via Surface-Initiated Atom Transfer Radical Polymerization: Synthesis, Applications, and Current Challenges.

Polymer brushes have received great attention in recent years due to their distinctive properties and wide range of applications. The synthesis of polymer brushes typically employs surface-initiated atom transfer radical polymerization (SI-ATRP) techniques. To realize the control of the polymerization process in different environments, various SI-ATRP techniques triggered by different stimuli have been developed. This review focuses on the latest developments in different stimuli-triggered SI-ATRP methods, such as electrochemically mediated, photoinduced, enzyme-assisted, mechanically controlled, and organocatalyzed ATRP. Additionally, SI-ATRP technology triggered by a combination of multiple stimuli sources is also discussed. Furthermore, the applications of polymer brushes in lubrication, biological applications, antifouling, and catalysis are also systematically summarized and discussed. Despite the advancements in the synthesis of various types of 1D, 2D, and 3D polymer brushes via controlled radical polymerization, contemporary challenges remain in the quest for more efficient and straightforward synthetic protocols that allow for precise control over the composition, structure, and functionality of polymer brushes. We anticipate the readers could promote the understanding of surface functionalization based on ATRP-mediated polymer brushes and envision future directions for their application in surface coating technologies.

Controlled Polymer Synthesis Toward Green Chemistry: Deep Insights into Atom Transfer Radical Polymerization in Biobased Substitutes for Polar Aprotic Solvents.

Cyrene (dihydrolevoglucosenone) and its derivative Cygnet 0.0, recognized as eco-friendly alternatives to polar aprotic solvents, were utilized in atom transfer radical polymerization (ATRP) of a wide range of both hydrophobic and hydrophilic (meth)acrylates. The detailed kinetics study and electrochemical experiments of the catalytic complex in these solvents reveal the opportunities and limitations of their use in controlled radical polymerization. Both solvents produce precisely controlled polymers using supplemental activator and reducing agent (SARA) ATRP. They offer an efficient reaction medium for crafting well-defined branched architectures from naturally derived cores such as riboflavin, β-cyclodextrin, and troxerutin, thereby significantly expanding the application scope of these solvents. Notably, Cygnet 0.0 significantly reduces side reactions between the solvent and the catalyst compared to Cyrene, allowing the catalyst complex to be used at a reduced concentration down to 75 ppm. The effective mass yield values achieved in Cyrene and Cygnet 0.0 underscore a substantial advantage of these solvents over DMF in generating processes that adhere to the principles of green chemistry. Furthermore, the copper residue in the final polymers was several hundred times lower than the permissible daily exposure to orally administered copper in pharmaceuticals. As a result, the resulting polymeric materials hold immense potential for various applications, including the pharmaceutical industry.

Antimony-Based Halide Perovskite Nanoparticles as Lead-Free Photocatalysts for Controlled Radical Polymerization.

Metal halide perovskites have emerged as versatile photocatalysts to convert solar energy for chemical processes. Perovskite photocatalyzed polymerization draws special attention due to its straightforward synthesis process and the ability to create advanced perovskite-polymer nanocomposites. Herein, this work employs Cs3 Sb2 Br9 perovskite nanoparticles (NPs) as a lead-free photocatalyst for light-controlled atom transfer radical polymerization (ATRP). Cs3 Sb2 Br9 NPs exhibit high reduction potential and interact with electronegative bromide initiator with Lewis acid Sb sites, enabling efficient photoinduced reduction of initiators and controlled polymerization under blue light irradiation. Methacrylate monomers with various functional groups are successfully polymerized, and the resulting polymer showcased a dispersity (Đ) as small as 1.27. The living nature of polymerization is confirmed by high chain end fidelity and kinetic studies. Moreover, Cs3 Sb2 Br9 NPs serve as heterogeneous photocatalysts, demonstrating recyclability and reusability for up to four cycles. This work presents a promising approach to overcome the limitations of lead-based perovskites in photoinduced controlled radical polymerization, offering a sustainable and efficient alternative for the synthesis of well-defined polymeric materials.

Highly hydrophilic methacrylamide-based copolymers as precursors for polymeric nanomedicines containing anthracyclines

The crucial limitation of most low molecular weight cytostatic drugs, including anthracyclines, is their nonspecific biodistribution causing severe adverse effects during cancer treatment. Recently, nanomedicines such as polymer-based systems have been developed as advanced drug delivery systems. Herein, we report the design, synthesis, and characterization of highly water-soluble polymer-carriers based on N‑(1,3‑dihydroxyprop-2-yl)methacrylamide (DHPMA). Polymers differing in molecular weight, hydrodynamic size, and dispersity were synthesized via free or controlled radical polymerization and conjugated to an anthracycline drug pirarubicin (THP) via a pH-sensitive hydrazone bond achieving up to 21 wt% of THP. The DHPMA copolymers were extensively compared to the well-known drug delivery vectors, N-(2-hydroxypropyl)methacrylamide (HPMA)-based copolymers. Importantly, DHPMA-based conjugates showed excellent hydrophilicity exceeding that of HPMA-based copolymers and did not aggregate even after loading with THP reaching 21 wt%. The DHPMA-based polymer nanomedicines exhibited excellent cytotoxicity, body biodistribution, tumor accumulation, and antitumor efficacy, significantly reducing the side effects and toxicity comparable to HPMA-based systems, thus demonstrating their applicability and suitability as efficient drug carriers.

Acid-triggered radical polymerization of vinyl monomers

Reversible addition–fragmentation chain-transfer (RAFT) polymerization is one of the most versatile and robust controlled radical polymerization methods owing to its broad material scope and high tolerance to various functionalities and impurities. However, to operate RAFT polymerization, a constant supply of radicals is required, typically via exogenous thermal radical initiators that are not only challenging to transport and store, but also primarily responsible for termination and end-group heterogeneity. Here we present an acid-triggered RAFT polymerization that operates in the dark and without any conventional radical initiator. Abundant acids (for example, sulfuric acid) are shown to have a dual role initiating and accelerating the polymerization. The polymers prepared have low dispersity and high end-group fidelity. The method is compatible with a wide range of vinyl monomers and solvents, and can be applied to the synthesis of well-controlled high molecular weight block copolymers, as well as to free radical polymerization.

Shake, shear, and grind! - the evolution of mechanoredox polymerization methodology.

In the last half decade, mechanoredox catalysis has enabled an entirely new genre of polymerization methodology. In this paradigm, mechanical force, such as ultrasonic cavitation bubble collapse or ball mill grinding, polarizes piezoelectric nanoparticles; the resultant piezopotential drives the redox processes necessary for free- and controlled-radical polymerizations. Since being introduced, evolution of these methods facilitates exploration of mechanistic underpinnings behind key electron-transfer events. Mechanical force has not only been identified as a "greener" alternative to more traditional reaction stimuli (e.g., heat, light) for the synthesis of commodity polymers, but also a potential technology to enable the production of novel thermoplastic and thermoset materials that are either challenging, or even impossible, to access using conventional solution-state approaches. In this Feature Article, significant contributions to such methods are highlighted within. Advances and ongoing challenges in both ultrasound and ball milling driven reactions for radical polymerization and crosslinking are identified and discussed.

Chemical recycling of bromine-terminated polymers synthesized by ATRP.

Chemical recycling of polymers is one of the biggest challenges in materials science. Recently, remarkable achievements have been made by utilizing polymers prepared by controlled radical polymerization to trigger low-temperature depolymerization. However, in the case of atom transfer radical polymerization (ATRP), depolymerization has nearly exclusively focused on chlorine-terminated polymers, even though the overwhelming majority of polymeric materials synthesized with this method possess a bromine end-group. Herein, we report an efficient depolymerization strategy for bromine-terminated polymethacrylates which employs an inexpensive and environmentally friendly iron catalyst (FeBr2/L). The effect of various solvents and the concentration of metal salt and ligand on the depolymerization are judiciously explored and optimized, allowing for a depolymerization efficiency of up to 86% to be achieved in just 3 minutes. Notably, the versatility of this depolymerization is exemplified by its compatibility with chlorinated and non-chlorinated solvents, and both Fe(ii) and Fe(iii) salts. This work significantly expands the scope of ATRP materials compatible with depolymerization and creates many future opportunities in applications where the depolymerization of bromine-terminated polymers is desired.

SYNTHESIS OF COPOLYMERS OF STEARYLMETHACRYLATE AND STEARYLACRYLATE WITH N-SUBSTITUTED ACRYLAMIDES IN THE PRESENCE OF REVERSIBLE CHAIN TRANSFER AGENTS AND STUDY OF THEIR EFFECT ON THE LOW-TEMPERATURE PROPERTIES OF DIESEL FUEL

The features of copolymerization of stearylacrylate (SA) and stearylmethacrylate with N-isopropylacrylamide and N,N-dimethylacrylamide in the presence of dibenzyltrithiocarbonate and 2-cyanoisopropyldodecyltrithiocarbonate as agents of reversible chain transfer have been studied. The choice of agents of reversible chain transfer (RAFT-agents) is due to the fact that sulfur-containing compounds with cyanoisopropyl radicals are most effective in the polymerization of methacrylic monomers, while benzyltrithiocarbonates are more active in the polymerization of acrylic monomers, as well as styrene and acrylonitrile. It has been established that polymerization of stearyl methacrylate (SMA) in the presence of RAFT-agents proceeds without a gel effect up to a high conversion. At the same time, although polystеarylmethacrylate samples are characterized by relatively high values of polydispersity coefficients (Mn/Mw) for controlled radical polymerization processes, they are nevertheless somewhat lower than for polymers of similar conversion synthesized in the absence of chain transfer agents. It has been shown that the process of copolymerization of stearyl acrylate and stearylmethacrylate with N-isopropylacrylamide and N,N-dimethylacrylamide in the presence of dibenzyltrithiocarbonate and 2-cyanoisopropyldodecyltrithiocarbonate proceeds without gelation to high conversions. The synthesized copolymers are characterized by a relatively narrow molecular weight distribution: the polydispersity coefficients of polymer samples vary from 1.18 to 1.57 in the case of using N-isopropylacrylamide and from 1.21 to 1.47 when using N,N-dimethylacrylamide as a comonomer to higher alkyl acrylates, which is typical for processes of radical polymerization proceeding in a controlled manner. At the same time, the synthesized copolymers exhibit a significant depressant effect when they are introduced into diesel fuel at a concentration of 1600 ppm. It has been established that copolymers of stearylmethacrylate and stearylacrylate with polar nitrogen-containing monomers have a more effective effect on the low-temperature properties of diesel fuel than homopolymers of stearylmethacrylate and stearylacrylate. At the same time, additives based on copolymers of stearylmethacrylate with N-isopropylacrylamide with a composition of 70/30 mol.% and stearylacrylate with N-isopropylacrylamide with a composition of 20/80 mol.% had the most significant effect on the low-temperature characteristics of the fuel.

RAFT polymerization of renewable monomers with dithiobenzoates: Effect of Z-group substituents and reaction conditions

The use of renewable polymer feedstocks has attracted significant attention recently due to increased concerns about petrochemical-based materials and limited fossil-based resources. As a promising candidate, lignin-derived monomers have been polymerized via controlled radical polymerization to yield bio-based materials. Arguably, the most commonly employed polymerization methodology is reversible-addition-fragmentation chain-transfer (RAFT) polymerization which utilizes, almost exclusively, 2-cyano-2-propyl benzodithioate as a chain transfer agent (CTA). Despite the robustness of this approach, polymerization of lignin-derived methacrylates is far more challenging than of the commonly used monomers (e.g. methyl methacrylate), often resulting in polymers with moderate control over the molecular weight and dispersity (Đ). To improve control over the RAFT polymerization, we investigate here a series of 2-cyano-2-propyl benzodithioate derivatives, where the electronic properties of the Z group were systematically altered. The introduction of electron-withdrawing groups in the para-position of the phenyl ring of the Z group increased control over the polymerization by improving the chain transfer coefficient of the CTA, resulting in enhanced control over molecular weights and lower Đs. Conversely, the incorporation of electron-donating groups had the opposite effect. 2-cyano-2-propyl 4-cyanobenzodithioate was found to be the optimal CTA for the polymerization of a series of lignin-derived monomers resulting in Đs < 1.25. The robustness of the system was highlighted by the synthesis of higher molecular weights polymers and the efficient chain-extension of macroCTAs; the latter case yielding bio-based block copolymers with a Đ as low as 1.16. This work highlights that RAFT polymerization can, upon judicious optimization, be successfully employed for the synthesis of renewable polymers.

Controlled polymerization in microfluidics: Advancement in nanogel synthesis

AbstractThis comprehensive review provides a detailed examination of controlled polymerization in the development of nanogels‐based microfluidic devices. Here, we have explored the integration of atom transfer radical polymerization (ATRP) and reversible addition‐fragmentation chain transfer (RAFT) techniques within microfluidic platforms for the synthesis of nanogels. The synergistic combination of ATRP and RAFT with microfluidics has emerged as a powerful tool for precise control over polymerization reactions, enabling the fabrication of well‐defined, multifunctional nanogels with tailored properties. The review begins with a thorough introduction to the principles of ATRP and RAFT, highlighting their respective advantages in controlled radical polymerization. Subsequently, it elucidates the principles of microfluidics and its profound impact on polymerization processes. The merging of these techniques enables precise control over reaction kinetics, monomer conversions, and molecular weight distributions, facilitating the synthesis of nanogels with unprecedented precision and reproducibility. Furthermore, this review delves into the chemical mechanisms underlying ATRP and RAFT reactions in microfluidic environments, emphasizing the role of various initiators, catalysts, and chain transfer agents. Special attention is given to the impact of microscale flow conditions on reaction kinetics and polymer structure. In addition, the review discusses emerging trends in the field, such as the incorporation of novel monomers and the exploration of environmentally benign reaction conditions.Highlights The controlled polymerization is the mechanism by which we can obtain tailormade material. The nanogel synthesis must ensure the gelation to be in confined dimensions here microfluidics plays key role.

Development of Novel Star-Like Branched-Chain Acrylamide (AM)-Sodium Styrene Sulfonate (SSS) Copolymers for Heavy Oil Emulsion Viscosity Reduction and Its Potential Application in Enhanced Oil Recovery.

Injecting water with chemicals to generate emulsions in the reservoir is a promising method for enhancing heavy oil recovery because oil-in-water (O/W) emulsions significantly reduce oil viscosity. To enhance heavy oil recovery efficiency, we developed new star-like branched AM-SSS copolymers (SB-PAMs) with reduction in the viscosity of the heavy oil emulsion, which was synthesized by reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization. The core structure of the branched polymer was RAFT polymerization of acrylamide (AM) and N,N'-methylene bis-acrylamide (BisAM), in the presence of 3-(((benzylthio)carbonothioyl)thio)propanoic acid as a chain transfer agent, followed by chain extension with AM and SSS. The core structures were achieved by incorporation of total monomer ratios [BisAM]/[AM] of 1:11. The expansion of the core structures by copolymerization of AM and SSS resulted in star-like branched polymer SB-PAM-co-SSS with apparent molecular weights ranging from 240 to 2381 kDa. 1H-nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) confirmed the synthesized polymer structure. The molecular weight was determined by gel permeation chromatography (GPC). The polydispersity coefficient was between 1 and 7, which has a broad molecular weight distribution. The polymer dissolves only 0.75 h in deionized water, faster than conventional polyacrylamide. At 50 °C, the viscosity of the 1000 mg/L SB-polymer solution can reach up to 45 mPa·s. First, heavy oil viscosity reduction by 800 mg/L SB polymer can reach 91.7%, at a water dehydration rate of 90.4%; second, with 0.6 PV injection, 800 mg/L SB polymer improved oil recovery up to 23.66% after water flooding; and third, SB-polymer-assisted hot water flooding shows that heavy oil recovery improved by 19.46% at 110 °C with 0.6 pore volume (PV) SB-polymer injection. This novel branched chain polymer with heavy oil emulsion capability will shed light on high-temperature polymer flooding and the development of a new candidate structure for heavy oil viscosity reduction.

Realizing Cross-linking-free Acrylic Pressure-Sensitive Adhesives with Intensive Chain Entanglement through Visible-Light-Mediated Photoiniferter-Reversible Addition-Fragmentation Chain-Transfer Polymerization.

A versatile and simplified synthesis scheme for intensively entangled acrylic pressure-sensitive adhesives (PSAs) was developed in this study by leveraging visible-light-driven controlled radical polymerization (photoiniferter/reversible addition-fragmentation chain-transfer polymerization) of acrylic copolymers under a controlled manner; the approach was differentiated by a single factor; molecular weight (Mw up to 2.8 MDa) with identical compositions. By manipulating Mw up to ultra-high ranges, PSAs with diversified viscoelastic properties were prepared and then assessed with a focus on realizing PSAs with a maximized degree of entanglement per chain through domination of high Mw contents, to help achieve excellent cohesiveness without a reinforcing cross-linking network. Moreover, fully linear solvent-soluble poly(acrylate)s were synthesized to facilitate reprocessing and reuse, highlighting the sustainability of the devised method and, consequently, its potential to be applied for effectively reducing industrial or daily waste.