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MALDI-ToF-MS spectra of (a) low dispersity (Đ = 1.08) PMA prepared with 0.02 equiv of ligand and (b) high dispersity (Đ = 1.53) PMA prepared with 0.00075 equiv of ligand.
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Cu(0)-reversible deactivation radical polymerization (RDRP) is a versatile polymerization tool, providing rapid access to well-defined polymers while utilizing mild reaction conditions and low catalyst loadings. However, thus far, this method has not been applied to tailor dispersity, a key parameter that determines the physical properties and appl...
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Context 1
... assess this, low (Đ = 1.08) and high dispersity PMA (Đ = 1.53) were synthesized, with the aforementioned conditions ( Figure S10 and Table S5). We then MALDI-ToF-MS of our two dispersity extremes (Figure 3a,b). In both cases, a single polymer distribution could be observed, with excellent correlation between the observed molecular weight and the expected values for PMA oligomers initiated by the expected ATRP initiator fragment and terminated with an active bromine, with each peak separated by the mass of one monomer unit. ...
Context 2
... regardless of the targeted dispersity, excellent preservation of the active bromine could be maintained. In addition, the increase in dispersity for the second polymer could also be evidenced by the extended mass range of the distribution and an increase in the number of polymeric species (Figure 3b). ...
Citations
... 27 In the area of controlled radical polymerization, both our group and the Matyzjasewski group illustrated that by lowering the catalyst concentration in atom transfer radical polymerization (ATRP), the dispersity of the resulting polymers could be incrementally increased. [28][29][30][31][32] In addition, it has been demonstrated that dispersity control was possible by adding a comonomer in organocatalyzed living radical polymerization (O-LRP) 33 and that by mixing chain transfer agents (CTAs) in reversible addition-fragmentation chain transfer (RAFT) polymerization, dispersity could be tuned while maintaining high end-group fidelity. [34][35][36] Most recently, our group expanded dispersity control to multiblock copolymers using a switchable CTA in thermal RAFT and by simply adding acid or base alongside each monomer, a low, intermediate or high dispersity block could be obtained. ...
... It is also worth highlighting that precisely obtaining the targeted molecular weight, even at high monomer conversion is not usually the case for many previously developed dispersity-controlled methodologies where a huge deviation from the theoretical values is typically observed when targeting high dispersity polymers. 28,30,31 As this work aims to subsequently apply the optimized conditions to the synthesis of network polymers, it is necessary to be able to attain comparable molecular weights regardless of the targeted primary chain dispersity as networks with comparable compositions are the ultimate goal. ...
Although dispersity has been demonstrated to be instrumental in determining many polymer properties, current synthetic strategies predominantly focus on tailoring the dispersity of linear polymers. In contrast, controlling the primary chain dispersity in network polymers is much more challenging, in part due to the complex nature of the reactions, which has limited the exploration of properties and applications. Here, a one-step method to prepare networks with precisely tuned primary chain dispersity is presented. By using an acid-switchable chain transfer agent and a degradable crosslinker in PET-RAFT polymerization, the in situ crosslinking of the propagating polymer chains was achieved in a quantitative manner. The incorporation of a degradable crosslinker, not only enables the accurate quantification of the various primary chain dispersities, post-synthesis, but also allows the investigation and comparison of their respective degradation profiles. Notably, the highest dispersity networks resulted in a 40% increase in degradation time when compared to their lower dispersity analogues, demonstrating that primary chain dispersity has a substantial impact on the network degradation rate. Our experimental findings were further supported by simulations, which emphasized the importance of higher molecular weight polymer chains, found within the high dispersity materials, in extending the lifetime of the network. This methodology presents a new and promising avenue to precisely tune primary chain dispersity within networks and demonstrates that polymer dispersity is an important parameter to consider when designing degradable materials.
... 46 Short reaction times, low temperatures and amounts of catalyst, as well as preservation of end groups and low dispersity, even at high conversion, have pushed it to the forefront of user-friendly controlled polymerization techniques. 47,48 Furthermore, this technique is highly versatile, permitting the tailoring of the polymers' molecular weight distribution 49 and is compatible with a wide range of monomers, 50 most of which can be reacted in water or nontoxic dimethyl sulfoxide (DMSO). Despite the ever-growing catalogue of Cu(0)-RDRP-made polymers, there have been�to the best of our knowledge�no reports on the synthesis of sulfonate-containing BCPs with this technique. ...
... In a first attempt, ethyl α-bromoisobutyrate (i.e., the initiator), ∼50 equiv of BSPA, tris[2-(dimethylamino)ethyl]amine (Me 6 -TREN, i.e., the ligand), and copper(II) bromide (CuBr 2 , i.e., the deactivator) were dissolved in dimethyl sulfoxide (DMSO). We deliberately introduced low amounts of CuBr 2 and Me 6 -TREN (respectively, 0.01 and 0.09 mol % to the initiator), as recent studies have demonstrated this to result in a more efficient polymerization 49 and simultaneous improvement of the livingness and a higher chance of chain extension 52 for large macromolecules at such ratios. After deoxygenation, a stirring bar wrapped with a freshly etched 4 cm copper wire was dropped into the mixture to start the polymerization. ...
Despite recent developments in controlled polymerization techniques, the straightforward synthesis of block copolymers that feature both strong anionic and charge-neutral segments remains a difficult endeavor. In particular, solubility issues may arise during the direct synthesis of strong amphiphiles and typical postpolymerization deprotection often requires harsh conditions. To overcome these challenges, we employed Cu(0)-mediated reversible deactivation radical polymerization (Cu(0)-RDRP) on a hydrophobic isobutoxy-protected 3-sulfopropyl acrylate. Cu(0)-RDRP enables the rapid synthesis of the polymer, reaching high conversions and low dispersities while using a single solvent system and low amounts of copper species. These macromolecules are straightforward to characterize and can subsequently be deprotected in a mild yet highly efficient fashion to expose their strongly charged nature. Furthermore, a protected sulfonate segment could be grown from a variety of charge-neutral macroinitiators to produce, after the use of the same deprotection chemistry, a library of amphiphilic, double-hydrophilic as well as thermoresponsive block copolymers (BCPs). The ability of these various BCPs to self-assemble in aqueous media was further studied by dynamic light scattering, ζ-potential measurements as well as atomic force and electron microscopy.
... Polymers are high molecular compounds consisting of macromolecules with different chain lengths [1]. The properties of polymers are affected by their molecular weight distribution (MWD) [2][3][4][5][6], which can be measured directly or modelled mathematically [7][8][9]. The production of polymers is widespread and long-standing in industrial processes; different applications need different specifications for the polymers [10]. ...
The molecular weight distribution is an important factor that affects the properties of polymers. A control algorithm based on the moment-generating function was proposed to regulate the molecular weight distribution for polymerization processes in this work. The B-spline model was used to approximate the molecular weight distribution, and the weight state space equation of the system was identified by the subspace state space system identification method based on the paired date of B-spline weights and control inputs. Then, a new performance criterion mainly consisting of the moment-generating function was constructed to obtain the optimal control input. The effectiveness of the proposed control method was tested in a styrene polymerization process. The molecular weight distribution of the styrene polymers can be approximated by the B-spline model effectively, and it can also be regulated towards the desired one under the proposed control method.
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.
Polyvinyl esters have wide range of applications; however, the synthesis of high molecular weight uniform polymers is an ongoing challenge. Vinyl ester monomers are among the less activated monomers compatible...
Quasi‐solid‐state lithium metal batteries (QSSLMBs) necessitate stable electro‐electrolyte interfaces to ensure reliable stationary power supply, thereby placing significant emphasis on the development of polymer electrolytes with high and uniform conductivity. However, while preparing the polymer electrolytes, the uncontrolled radical polymerization process of polymer electrolytes often leads to localized phase agglomeration, resulting in inhomogeneous physiochemical properties. In this study, a method is proposed to regulate the micro‐phase structure, aiming to substantially enhance the homogeneity of physiochemical properties, specifically the ionic conductivity, through the optimization of organic monomer polymerization behavior. This proposed polymer electrolyte determines enhanced reaction kinetics and reactivity at the interfaces, thereby effectively regulating the Li plating/stripping behavior and mitigating dendrite formation. The Li||Li symmetrical cell employing the proposed polymer electrolyte demonstrates exceptional cyclic durability, surpassing 1000 h at 0.2 mA cm⁻². Additionally, the QSSLMBs employing high‐voltage LiCoO2 as the cathode exhibit remarkable improvements in electrochemical performance, particularly in terms of cycling stability. The insights derived from this research suggest that the regulation of micro‐phase structure in polymer electrolytes represents a promising strategy to enhance the practicability of QSSLMBs.
Reversible deactivation radical polymerization of hydrophilic monomers in water is often poorly controlled due to several side reactions. It results in polymers with broad molecular weight distributions. As presented, this can be improved by the polymerization of hydrophilic monomers in an inverse dispersion system. From an ecological point of view, the use of environmentally friendly continuous phases is desirable. We present herein the synthesis of a well-controlled, high molecular weight water-soluble polymer, poly(2-hydroxyethyl acrylate), in a vegetable oil-based inverse emulsion using activators regenerated by electron transfer atom transfer radical polymerization mediated by ascorbic acid. Various reaction parameters, including the type of vegetable oil, the surfactants used, the reaction temperature, and the volume ratio of the continuous and dispersed phases, were examined to determine their impact on the emulsion stability, polymerization kinetics, and properties of the final polymer. This approach enables the synthesis of low dispersity, high molecular weight polymers, reaching Mn up to 200,000, higher than when polymerizing HEA in aqueous homogeneous solution. The retention of polymer chain-end fidelity was confirmed by chain extension experiments. The use of vegetable oil as a continuous phase instead of typical toxic organic solvents represents a significant advancement toward the scalable production of water-soluble, high molecular weight polymers.
