Acrylic Monomers Research Articles

An Electrode-Crosstalk-Suppressing Smart Polymer Electrolyte for High Safety Lithium-Ion Batteries.

Electrode crosstalk between anode and cathode at elevated temperatures is identified as a real culprit triggering the thermal runaway of lithium-ion batteries. Herein, to address this challenge, a novel smart polymer electrolyte is prepared through in situ polymerization of methyl methacrylate and acrylic anhydride monomers within a succinonitrile-based dual-anion deep eutectic solvent. Owing to the abundant active unsaturated double bonds on the as-obtained polymer matrix end, this smart polymer electrolyte can spontaneously form a dense crosslinked polymer network under elevated temperatures, effectively slowing down the crosstalk diffusion kinetics of lithium ions and active gases. Impressively, LiCoO2/graphite pouch cells employing this smart polymer electrolyte demonstrate no thermal runaway even at the temperature up to 250°C via accelerating rate calorimeter testing. Meanwhile, because of its abundance of functional motifs, this smart polymer electrolyte can facilitate the formation of stable and thermally robust electrode/electrolyte interface on both electrodes, ensuring the long cycle life and high safety of LIBs. In specific, this smart polymer electrolyte endows 1.1AhLiCoO2/graphite pouch cell with a capacity retention of 96% after 398 cycles at 0.2 C.

Selective and Controlled Grafting from PVDF-Based Materials by Oxygen-Tolerant Green-Light-Mediated ATRP.

Poly(vinylidene fluoride) (PVDF) shows excellent chemical and thermal resistance and displays high dielectric strength and unique piezoelectricity, which are enabling for applications in membranes, electric insulators, sensors, or power generators. However, its low polarity and lack of functional groups limit wider applications. While inert, PVDF has been modified by grafting polymer chains by atom transfer radical polymerization (ATRP), albeit via an unclear mechanism, given the strong C-F bonds. Herein, we applied eosin Y and green-light-mediated ATRP to modify PVDF-based materials. The method gave nearly quantitative (meth)acrylate monomer conversions within 2 h without deoxygenation and without the formation of unattached homopolymers, as confirmed by control experiments and DOSY NMR measurements. The gamma distribution model that accounts for broadly dispersed polymers in DOSY experiments was essential and serves as a powerful tool for the analysis of PVDF. The NMR analysis of poly(methyl acrylate) graft chain-ends on PVDF-CTFE (statistical copolymer with chlorotrifluoroethylene) was carried out successfully for the first time and showed up to 23 grafts per PVDF-CTFE chain. The grafting density was tunable depending on the solvent composition and light intensity during the grafting. The initiation proceeded either from the C-Cl sites of PVDF-CTFE or via unsaturations in the PVDF backbones. The dehydrofluorinated PVDF was 20 times more active than saturated PVDF during the grafting. The method was successfully applied to modify PVDF, PVDF-HFP, and Viton A401C. The obtained PVDF-CTFE-g-PnBMA materials were investigated in more detail. They featured slightly lower crystallinity than PVDF-CTFE (12-18 vs 24.3%) and had greatly improved mechanical performance: Young's moduli of up to 488 MPa, ductility of 316%, and toughness of 46 × 106 J/m3.

A deep-curing UV-LED light photoinitiator based on diphenylpropanetrione

Benzophenone is a widely used type II photoinitiator, whose application is somewhat limited due to these shortcomings, such as short absorption wavelength, requirement for initiation with a co-initiator like tertiary amine and propensity to yellowing. In this study, 1,3-diphenylpropyltriacetone (DPPT) was synthesized and its photopolymerization was evaluated. Due to the adjacent conjugation of the tricarbonyl group, it has an absorption band at 400–500 nm. The photopolymeirzaition process of DPPT was tested by using real time FT-IR under 365 and 405 nm LED irradiation for various acrylate monomers. Interestingly, the results showed that the initiation efficiency of DPPT was improved by OH-containing monomers or alcohols. ESR-ST and steady-state photolysis experiments demonstrated that the benzoyl radicals were generated, but the photoreaction was expedited by the structure of the addition products of the central carbonyl group of DPPT and alcohol. Furthermore, the DPPT/alcohol initiator could be used for deep curing due to the light bleach property.

Gamma radiation-induced grafting of poly(butyl acrylate) onto ethylene vinyl acetate copolymer for improved crude oil flowability

Ethylene vinyl acetate (EVA) copolymers are widely employed as pour point depressants to enhance the flow properties of crude oil. However, EVA copolymers have limitations that necessitate their development. This work investigated the modification of EVA via gamma radiation-induced grafting of butyl acrylate (BuA) monomers and the evaluation of grafted EVA as a pour point depressant for crude oil. The successful grafting of poly(butyl acrylate) p(BuA) onto EVA was verified through grafting parameters, FTIR spectroscopy, and 1H NMR spectroscopy. Treating crude oil with 3000 ppm of (EVA)0kGy, (EVA)50kGy, and (1EVA:3BuA)50kGy yielded substantial reductions in pour point of 24, 21, and 21 °C, respectively. Also, rheological characterization demonstrated improving evidenced by a viscosity reduction of 76.20%, 67.70%, and 71.94% at 25 °C, and 83.16%, 74.98%, and 81.53% at 12 °C. At low dosages of 1000 ppm, the EVA-g-p(BuA) exhibited superior pour point reductions compared to unmodified EVA, highlighting the benefit of incorporating p(BuA) side chains. The grafted EVA copolymers with p(BuA) side chains showed excellent potential as crude oil flow improvers by promoting more effective adsorption and co-crystallization with paraffin wax molecules.

Fabrication of core-shell polyacrylate latex pressure sensitive adhesives modified by fluorinated monomer and film properties

In this work, a series of fluorinated core-shell polyacrylate latex pressure sensitive adhesives (PSAs) were successfully synthesized through monomer-starved seeded semi-continuous emulsion polymerization. Specifically, (meth)acrylate monomers were employed as the main materials, with dodecafluoroheptyl methacrylate (DFMA) were used as modified monomer. The impact of fluorine monomer DFMA on the resulting core-shell latex and PSA properties was thoroughly examined. FTIR analysis confirmed the successful incorporation of DFMA into the latex copolymer through emulsion polymerization. TEM images illustrated that the morphology of latex particles exhibit a distinct core-shell structure. The results also showed that with the addition of DFMA, the water absorption and water whitening of the latex films decreased, while the water contact angle and thermal stability are improved. Interestingly, the latex films with DFMA added to the shell phase exhibit a larger WCA value when compared to those with DFMA in the core phase, further confirmed by XPS results. Finally, the adhesive properties of the fluorinated core-shell acrylate PSA were evaluated. The results of shear strength and gel content demonstrate that the prepared PSA exhibits excellent cohesive properties. Thus, this work could present a feasible strategy for optimizing the comprehensive properties of acrylate latex PSAs.

Construction of Weakly Hybridized Excited State Using Donor‐π‐Acceptor Structure and Applications: From Highly Efficient Pure‐Blue Electro‐Fluorescence to Visible‐Light Polymerization

AbstractHerein this work, a novel donor‐π‐acceptor (D‐π‐A) pure‐blue hybrid local and charge‐transfer (HLCT) fluorescent material TDFBO and its functionalization as organic light emitting diode (OLED) emitter and photoinitiator (PI) in photopolymerization is reported. The weak‐hybridization property involved by the fluorene π‐bridge can simultaneously give satisfied photo‐luminescent quantum yield (PLQY) and make efficient “hot‐exciton” channel achievable. Moreover, the D‐π‐A structure can also promote an exceeding electron mobility as high as 3.57×10−4 cm2 V−1 s−1. Finally, it is noted that the TDFBO‐doped OLED can be regarded as the best one among the pure‐blue emissive OLEDs, which exhibits a high maximum external quantum efficiency of 11.1%, while the rolling‐off only stands on a low level, as 6% at 100 cd m−2. Additionally, a relatively high final conversion of C = C double bond in a representative acrylate monomer is also attained by photoinitiation of TDFBO under 405 nm LED, where the photopolymerization has been applied to 3D printing.

Thermoplastic elastomer obtained by photopolymerization‐induced concomitant macrophase and microphase separations

AbstractWe report on concomitant photoinitiated polymerization‐induced macrophase and microphase separation strategies to produce hierarchically structured recyclable poly(n‐butyl acrylate) based elastomeric materials. The investigated crosslinker‐free formulations are composed of n‐butyl acrylate monomer and a UV photo‐initiator mixed with poly(methyl methacrylate)‐b‐poly(n‐butyl acrylate)‐poly(methyl methacrylate) ABA triblock copolymers. Two different pre‐synthesized copolymers are used to control the macrophase separation. One synthesized by nitroxide‐mediated radical polymerization (NMRP), and a second by anionic polymerization (AP). Essentially, NMRP route leads to copolymer with unsaturated chain ends, activated during UV photopolymerization. On the other hand, the copolymer synthesized by AP are chemically inert. That dissimilarity is also highlighted by time‐resolved FTIR and SAXS, performed to monitor respectively monomer conversion and nanostructure evolution during photopolymerization. The experimental data demonstrate that the reactivity of the triblock copolymer impacts drastically the polymerization kinetics and the self‐assembly processes. Finally, the rheological analysis shows that the produced materials present a solid‐like behavior at low frequencies despite a large PnBA content (i.e., 85 wt%). This property is associated to the phase segregation and to the sample hierarchical morphology.

Coumarin based glyoxylate photoinitiators for free radical and cationic Photopolymerizations with UV-Visible LED irradiation

High-performance photoinitiators (PIs) play a crucial role in ultraviolet–visible (UV–Vis) photopolymerization. In this study, three coumarin-3-oxoacetic acid methyl esters (COAEs) which demonstrate significant UV–Vis absorption within the 300–500 nm range were synthesized and studied. Real-time fourier transform infrared (RT-FTIR) and photo-differential scanning calorimetry (photo-DSC) experiments demonstrated that these PIs can function as Type I and Type II PIs for initiating free radical polymerization (FRP) of acrylate monomers. Additionally, they can serve as photosensitizers for iodonium salts and sulfonium salts, enabling cationic photopolymerization (CP) of epoxy and oxetane monomers. Remarkably, even at low concentrations of 0.01 wt%, they can effectively initiate the deep curing of Tri-(propylene glycol) diacrylate (TPGDA) to a depth of approximately 9 cm after 5 min of irradiation with a 415 nm or 450 nm LED light source. Furthermore, the COAEs exhibit satisfactory photobleaching properties, making them suitable for colorless applications in photopolymerization. The photochemical and photophysical properties of the COAEs were thoroughly investigated using absorption spectroscopy, electron spin resonance, cyclic voltammetry experiments, and photoinduced decarboxylation experiments to elucidate the photoinitiation mechanism. Cytotoxicity experiments revealed that COAE-N exhibited good cytocompatibility. Therefore, the exceptional polymerization properties of COAEs offer promising prospects for FRP and CP applications. Additionally, their efficient photobleaching characteristics make them highly suitable for deep photopolymerization applications. Moreover, the low cytotoxicity of COAEs suggests significant potential for biomedical applications such as dental restoration.

Correlation between the Chemical Structure of (Meth)Acrylic Monomers and the Properties of Powder Clear Coatings Based on the Polyacrylate Resins.

This paper presents studies on the influence of the chemical structure of (meth)acrylic monomers on the properties of powder coatings based on polyacrylate resins. For this purpose, a wide range of monomers were selected-2-hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), n-butyl acrylate (nBA), tert-butyl acrylate (tBA), dodecyl acrylate (DA), ethyl acrylate (EA) and benzyl acrylate (BAZ)-for the synthesis of the polyacrylate resin. The average molecular mass and molecular mass distribution of the synthesized resins were measured by gel permeation chromatography (GPC). The glass transition temperature (Tg) and viscosity of polyacrylate resins were determined by using differential scanning calorimetry (DSC) and a Brookfield viscometer. These parameters were necessary to obtain information about storage stability and behavior during the application of powder clear coatings. Additionally, DSC was also used to checked the course of the low-temperature curing reaction between the hydroxyl group contained in the polyacrylate resin and the blocked polyisocyanate group derived from a commercial agent such as Vestanat B 1358/100. The properties of the cured powder clear coatings were tested, such as: roughness, gloss, adhesion to the steel surface, hardness, cupping, scratch resistance, impact resistance and water contact angle. The best powder clear coating based on the polyacrylate resin L_HEMA/6MMA/0.5nBA/0.5DA was characterized as having good scratch resistance (550 g) and adhesion to the steel surface, a high water contact angle (93.53 deg.) and excellent cupping (13.38 mm). Moreover, its crosslinking density (CD) and its thermal stability was checked by using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA).

Nanoparticles bearing germanium based photoinitiators at their surface: Preparation and use in grafting-from photopolymerization reactions

In recent decades, there has been a growing interest in surface modifications utilizing “grafting-from” techniques within both industrial and academic fields. Among others, this technology continues to drive innovation in biomedicine, enabling the design and fabrication of advanced materials and devices with tailored properties for a wide range of applications, from regenerative medicine and drug delivery to diagnostics and therapeutics. This strategy relies on the covalent attachment of (photo)initiating species to surfaces. The coupled initiators are exploited to produce reactive sites such as radicals upon exposure to heat or light. Subsequently, polymerization reactions are induced, leading to surface coupled polymer brushes.In order to provide new perspectives in surface modification techniques, we present a novel and unique method for producing mesoporous organic/inorganic hybrid nanoparticles via the “grafting-from” method. This was accomplished by immobilizing a novel, low-toxic and visible light sensitive photoinitiator (based on triacylgermanium moieties) onto silica nanoparticles. Surface-initiated photopolymerizations of styrene and acrylate monomers were conducted to produce polymer shells on the surface of the nanoparticles. The grafted layers had a thickness in the range of 6–12 nm. Furthermore, the polymer grafting density is discussed in detail ranging between 0.17 and 0.23 chains per square nanometer.

A single-component LED excited enone photoinitiator for colorless and transparent antibacterial film preparation

Photoinitiators (PIs), as the key substances for photopolymerized antibacterial film (PAF), affect the cure rate and color of PAF. Herein, two enone dyes were designed and synthesized by a facile approach. Among the candidates, BDO1 has demonstrated the ability to initiate polymerization of acrylate monomers as single-component PI with the advantages of low mobility, outstanding photobleaching, excellent cytocompatibility, and suitability for light emitting diode (LED) light sources above 365 nm. Taking BDOs as examples, a novel method based on theoretical calculations aiming to assess the potential of enone molecules as single-component PIs was proposed. Finally, under the initiation of BDO1, tannic acid was photopolymerized to a colorless and transparent antibacterial film with high antibacterial ability, which indicated that BDO1 was expected to be used in environmentally friendly PAF.

Evaluating physiochemical characteristics of tragacanth gum-gelatin network hydrogels designed through graft copolymerization technique

The present work deals with the evaluation of the physiochemical and biomedical properties of hydrogels derived from copolymerization of tragacanth gum (TG) and gelatin for use in drug delivery (DD) applications. Copolymers were characterized by field emission-scanning electron micrographs (FE-SEM), electron dispersion X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. FE-SEM revealed heterogeneous morphology and XRD analysis demonstrated an amorphous nature with short range pattern of polymer chains within the copolymers. The release of the drug ofloxacin occurred through a non-Fickian diffusion mechanism and the release profile was best described by the Korsmeyer-Peppas kinetic model. The hydrogels exhibited blood compatibility and demonstrated a thrombogenicity value of 75.63 ± 1.98 % during polymer-blood interactions. Polymers revealed mucoadhesive character during polymer-mucous membrane interactions and required 119 ± 8.54 mN detachment forces to detach from the biological membrane. The copolymers illustrated the antioxidant properties as evidenced by 2, 2′-diphenylpicrylhydrazyl (DPPH) assay which demonstrated a 65.71 ± 3.68 % free radical inhibition. Swelling properties analysis demonstrated that by change in monomer and cross linker content during the reaction increased the crosslinking of the network. These results suggest that the pore size of network hydrogels could be controlled as per the requirement of DD systems. The copolymers were prepared at optimized reaction conditions using 14.54 × 10−1 molL−1 of acrylic acid monomer and 25.0 × 10−3 molL−1 of crosslinker NNMBA. The optimized hydrogels exhibited a crosslink density of 2.227 × 10−4 molcm−3 and a mesh size of 7.966 nm. Additionally, the molecular weight between two neighboring crosslinks in the hydrogels was determined to be 5332.209 gmol−1.The results indicated that the combination of protein-polysaccharide has led to the development of hydrogels suitable for potential applications in sustained drug delivery.

Cellulose-reinforced highly stretchable and adhesive eutectogels as efficient sensors

A cellulose-reinforced eutectogel was constructed by deep eutectic solvent (DES) and cotton linter cellulose. Cellulose was dispersed in the ternary DES consisting of acrylic acid, choline chloride and AlCl3·6H2O. The photoinitiator was then introduced into the system to in situ polymerize acrylic acid monomer to form transparent and ionic conductive eutectogels while keeping all the DES. The crosslinks formed by Al3+ induced ionic bonds and reversible links formed by hydrogen bonds give the eutectogels high stretchability (3200 ± 200 % tensile strain), self-adhesive (52.1 kPa to glass), self-healing and good mechanical strength (670 kPa). The eutectogels were assembled into sensors and epidermal patch electrodes that demonstrated high quality human motion sensing and physiological signal detection (electrocardiogram and electromyography). This work provides a facile way to design flexible electronics for sensing.

Electrically programmable color and shape morphing in photonic glass elastomers with reduced voltages

Electrochromic materials that integrate structural colors and dielectric elastomer actuators (DEAs) can simultaneously change colors and shapes upon voltages. Typically, operation voltages for these materials are high, reaching several kilovolts. To achieve color changes at lower voltages, we reduce the modulus by lowering silica nanoparticle volume fraction and adding a secondary acrylate monomer, while also ensuring that photonic elastomers maintain recognizable colors. We utilize binary silica nanoparticles to make photonic glass elastomers that show angle-independent structural colors. The photonic glass DEA shows color changes of 85 nm at 800 V with color change sensitivity of 0.11 nm/V, surpassing previous reports. By making a double-layered DEA, we can not only control the shape changes, but also increase the color contrast. This solid-state elastic electrochromic material, offering programmable color change and shape morphing, holds broad applications in wearable devices, camouflage, and flexible displays.

Polyacrylate modified alkyd hybrid latex with high anti-corrosion performance synthesized via solvent-free and emulsifier-free method

Polyacrylate modified alkyd hybrid emulsion (SPA-WAR) was prepared by solvent-free and emulsifier-free method to solve the problem of contamination of organic solvent in the preparation of alkyd resin. The originality of this paper lies in the special introduction of acrylic monomers. On the one hand, as a solvent, acrylic monomers play the role of reflux and dilution to reduce viscosity and drainage. On the other hand, as reactive monomers, acrylate monomers were grafted to alkyd resin to form macromolecular polymer. Due to the presence of hydrophilic groups in the polyacrylate chain, SPA-WAR can be obtained without the use of surfactants. This method does not need to add additional solvents and emulsifiers, and has the advantages of green environmental protection. Since the acrylate monomer plays the role of reflux condensation, the yield will also be greatly improved. In addition, compared with water-based alkyd resin (WAR) and acrylate-modified alkyd resin prepared by solvent method (PA-WAR), the particle size of SPA-WAR latex is smaller and the surface of SPA-WAR film is smoother. SPA-WAR coating has excellent physical properties and anti-corrosion properties. After 180 h salt spray treatment, SPA-WAR-latex coated tinplate has no obvious corrosion and diffusion.

Synthesis of Novel (Meth)acrylates with Variable Hydrogen Bond Interaction and Their Application in a Clear Viscoelastic Film.

Clear viscoelastic films (CVFs) have many applications in the display industry. Acrylic monomers containing a hydrogen bond (H-monomer) are often used in the preparation of CVF to increase the cohesion and form favorable interactions with the display substrate. Common H-monomers face a counterbalance between the glass transition temperature (Tg) and the hydrogen-bonding association constant (Ka). Strong hydrogen bonding often leads to a high Tg and high modulus, which are unfavorable in certain applications such as foldable display. To solve these problems, four types of hydrogen-bonding (meth)acrylic monomers (carbamate acrylate, carbamate methacrylate, urea acrylate, and urea methacrylate) with different Ka and Tg were readily synthesized. Among them, urea acrylates displayed the highest Ka while still maintaining moderate Tg. These H-monomers were copolymerized with 2-ethylhexyl acrylate (EHA) and cross-linked to obtain a series of copolymers (H-copolymers) as pressure-sensitive adhesives. After the characterization of rheology, optics, and peel adhesion, urea-acrylic H-copolymers showed the best overall performance by combining great optical property (>98% in transmittance, < 1% in haze) and mechanical performance (8-12 N/25 mm in peel adhesion, 84-92% in creep recovery). This work provides a new path to prepare acrylic CVF for flexible display application.

Preparation and properties of cationic waterborne polyurethane/acrylate for fluorine‐free water repellents

AbstractIn this work, cationic waterborne polyurethane/acrylate (WPUA) was synthesized for water repellent in cotton fabrics to replace fluorine‐containing finishing agents with the concerns of ecosystems and human health. First, the tertiary amines monomers, N‐methyl diethanolamine, 3‐dimethylamine‐1, 2‐propylene glycol, N,N′‐bis (2‐hydroxyethyl)piperazine, were used as chain extenders to prepare waterborne polyurethane, respectively. Long‐chain octadecyl acrylate monomers were then grafted to the waterborne polyurethane by a self‐emulsifying method. The stable WPUA suspensions of positively charged latexes were obtained and could be finished on cotton fabrics via a simple pad‐curing process. The coated cotton fabrics were capable of repelling common liquids without any penetration, and the contact angles of the treated cotton fabrics could reach 150°. The WPUA latex films also exhibited good tensile mechanical properties and thermal dimensional stability. The cotton fabric coated with the WPUA showed good laundering durability, and its static water contact angle was still maintained at 142° even after 50 times washing. This work not only highlights the structural design and preparation but also provides a feasible strategy for fluorine‐free water repellency in cotton fabrics, which has great potential application prospects for a variety of fields.

Dual‐Wavelength Vat Photopolymerization 3D Printing with Hybrid Acrylate‐Epoxy Resins: Influence of Resin Composition on Microstructure and Mechanical Properties

Dual‐wavelength vat photopolymerization 3D printing represents a convenient technology for the fabrication of objects with heterogeneous and locally controlled mechanical properties. By using two λ‐orthogonal cross‐linking reactions, it is possible to produce soft and stiff photopolymers with a single resin vat by switching the light source. Herein, hybrid acrylate‐epoxy resins are selectively cured by using either visible or UV light. At 405 nm, a free radical curing of the acrylate monomers is induced while irradiation with 365 nm triggers an additional cationic ring opening reaction of the epoxy monomer yielding interpenetrating photopolymer networks. In a comprehensive approach, the influence of the resin composition and the applied wavelength on cure kinetics, film morphology, (thermo)mechanical properties, and printability are studied. Fully separated as well as homogenous network morphologies are obtained depending on the ratio between acrylate and epoxy monomers, cure rate and applied light source (405 vs 365 nm). In general, glass transition temperature, stiffness, and tensile strength of the photopolymers increase with rising epoxy content. In contrast, a higher epoxy concentration in combination with a higher amount of the cationic photoinitiator compromises on the system's orthogonality, giving rise to the important role of the resin composition in dual‐wavelength vat photopolymerization 3D printing.

Tailoring Hierarchical Structure and Rare Earth Affinity of Compositionally Identical Polymers via Sequence Control.

Macromolecule sequence, structure, and function are inherently intertwined. While well-established relationships exist in proteins, they are more challenging to define for synthetic polymer nanoparticles due to their molecular weight, sequence, and conformational dispersities. To explore the impact of sequence on nanoparticle structure, we synthesized a set of 16 compositionally identical, sequence-controlled polymers with distinct monomer patterning of dimethyl acrylamide and a bioinspired, structure-driving di(phenylalanine) acrylamide (FF). Sequence control was achieved through multiblock polymerizations, yielding unique ensembles of polymer sequences which were simulated by kinetic Monte Carlo simulations. Systematic analysis of the global (tertiary- and quaternary-like) structure in this amphiphilic copolymer series revealed the effect of multiple sequence descriptors: the number of domains, the hydropathy of terminal domains, and the patchiness (density) of FF within a domain, each of which impacted both chain collapse and the distribution of single- and multichain assemblies. Furthermore, both the conformational freedom of chain segments and local-scale, β-sheet-like interactions were sensitive to the patchiness of FF. To connect sequence, structure, and target function, we evaluated an additional series of nine sequence-controlled copolymers as sequestrants for rare earth elements (REEs) by incorporating a functional acrylic acid monomer into select polymer scaffolds. We identified key sequence variables that influence the binding affinity, capacity, and selectivity of the polymers for REEs. Collectively, these results highlight the potential of and boundaries of sequence control via multiblock polymerizations to drive primary sequence ensembles hierarchical structures, and ultimately the functionality of compositionally identical polymeric materials.

New ketoxime ester-amine photoinitiator based on charge transfer complex for free radical LED polymerization

Recently, visible-light polymerization has received increasing attention because of the development of LED sources and the innovation of photopolymerization technology, which is derived from different strategies to design photoinitiating systems such as the construction of D-π-A-type photoinitiators or the use of up-conversion nanoparticles. However, the association of electron donor and acceptor molecules to form a charge-transfer complex (CTC) for polymerization has rarely been reported. Hence, a ketoxime ester (PFO) with a pentafluorophenone ring as an electron-defect acceptor has been designed and synthesized as a photosensitizer. Our investigation results showed that CTCs could be formed by associating PFO with amines that contain electron-rich rings and process a better absorption property in the visible-light region than PFO. Moreover, the two kinds of free radicals with high photoactivity were generated from CTCs via photochemical transformation, such as intermolecular charge transfer and α-cleavage, which can play a role in initiating the polymerization of acrylate monomers, and the efficiency of initiating polymerization is higher than that of PFO alone under LED@395–425 nm irradiation.