Acrylic Monomers Research Articles

Push–pull biphenyl–based iodonium salts: Highly sensitive one-component photoinitiators for photopolymerization under UV–visible LEDs

Diaryliodonium salts play an important role as highly efficient photoinitiators in the field of photopolymerizations. They can rapidly photodecompose to produce free radicals and super acids; thus, can initiate highly efficient photocuring of acrylic and epoxy monomers and resins. However, the absorption of commercialized diphenyliodonium salts is poorly matched with popular LED light sources, and the participation of sensitizers is usually required to achieve efficient photoexcitation. Here, we synthesized five new phenyl biphenyl iodonium salts with different electron-pushing and electron-withdrawing substituents, e.g., methoxy and CN, at the biphenyl substituent. Our results demonstrate that all synthesized iodonium salts have strong absorption in the range (λmax = 258–352 nm; εmax = 21,300–29,900 M−1 cm−1). The photochemistry of these synthesized iodonium salt is strongly influenced by substituents on the biphenyl ring. All iodonium salts can undergo rapid photolysis under light excitation, with higher quantum yield of photoacid generation reaching 0.25 and can quickly initiate cationic photopolymerization of epoxy monomers. Furthermore, free radicals are generated during photolysis, which can successfully trigger free radical polymerization. These iodonium salts with good absorbance in the UVA band demonstrate their potential as excellent photoinitiators under 365–405 nm LED excitation.

A self-healing waterborne acrylic latex coating based on intrinsic hydrogen bonding

Acrylic coatings suffer damage in the form of cracking, which degrades both their protective and aesthetic performance over time. Self-healing technology offers the ability to solve this problem by allowing cracks to spontaneously heal without external diagnosis or intervention, offsetting the enormous costs associated with coating damage and repair. However, there is currently no efficient self-healing acrylic coating design, and research in the area remains noticeably sparse. In this research we sought to imbue a mechanically tough methyl methacrylate (MMA)/butyl acrylate (BA)/acrylic acid (AA) acrylic coating with self-healing functionality by incorporating self-healing monomers within the formulation. We synthesized a library of four acrylic monomers containing both a long amphiphilic spacer of variable length, and the 2-ureido-4[1H]-pyrimidinone (UPy) unit, which forms strong self-complementary quadruple hydrogen bonds. These UPy-monomers were able to participate in the emulsion polymerization of MMA, BA and AA, forming intrinsic hydrogen bonding networks within the subsequent acrylic coatings. These UPy functionalized coatings displayed optical self-healing and strain recovery over 24 h both at room temperature (∼28 %), and at elevated temperatures up to 50 °C (∼80 %). The coatings also displayed repeatable self-healing after four healing cycles, relative to an MMA/BA/AA coating.

Precise recognition and efficient recovery of Pd(II) from high-level liquid waste by a novel aminothiazole-functionalized silica-based adsorbent

Efficient recognition, separation and recovery of palladium from high-level liquid waste (HLLW) not only helps the safe, green and environmentally friendly disposal of nuclear waste, but also is an essential important supplement to overcome the growing shortage of natural palladium resources. Herein, a novel silica-based functional adsorbent named 2AT-SiAaC was prepared by a two-step method, i.e., grafting of 2-aminothiazole (2AT) via the amidated reaction after in-situ polymerization of acrylic monomers on porous silica. SEM, EDS, TG-DSC, BET and PXRD all proved the successful preparation of 2AT-SiAaC, and it exhibited ultrahigh adsorption selectivity for Pd(II) (Kd (distribution coefficient) ≥ 10,344.2 mL/g, SFPd/M (separation factor) ≥ 613.7), fast adsorption kinetics with short equilibrium time (t ≤ 1 h) and good adsorption capacity (Q ≥ 62.1 mg Pd/g). The dynamic column experiments shows that 2AT-SiAaC achieved efficiently separation of Pd(II) from simulated HLLW, and the enrichment coefficients (C/C0) of Pd(II) was as high as about 14 with the recovery rate nearly 99.9% and basically kept the same performance in three adsorption-desorption column cycle experiments. The adsorption mechanism was analyzed by FT-IR, XPS and DFT calculations, and the ultrahigh selectivity of 2AT-SiAaC was attributed to the preferred affinity of the soft N-donor atoms in 2AT for Pd(II). NO3− ions participated in the adsorption reaction to keep charge balance, and the frontier orbital electron density distribution diagram shows the charge transfer in the process of material preparation and adsorption. To sum up, 2AT-SiAaC adsorbent provided a new insight for precise recognition and efficient separation of Pd(II) from HLLW.

Synthesis of Amphiphilic Block Copolymer and Its Application in Pigment-Based Ink.

Amphiphilic block copolymers-based aqueous color inks show great potential in the field of visual communication design. However, the conventional step-by-step chemistry employed to synthesize the amphiphilic block copolymers is intricate, with low yield and high economic and environmental costs. In this work, we present a novel method for preparing an amphiphilic AB di-block copolymer of PCL-b-PAA by employing a combined polymerization strategy that involves both cationic ring-opening polymerization (ROP) of the ε-caprolactone monomer and the reversible addition-fragmentation chain-transfer (RAFT) polymerization on the acrylic acid monomer simultaneously. The corresponding polycaprolactone (PCL) and polyacrylic acid (PAA) serve as the hydrophobic and hydrophilic units, respectively. The effectiveness of the amphiphilic AB di-block copolymer as the polymeric pigment dispersant for water-based color inks is evaluated. The amphiphilic AB di-block copolymer of PCL-b-PAA exhibits a molecular weight of 1400 g mol-1, which is consistent with the theoretical value and suitable for polymeric dispersant application. The high surface excess (Γmax) of the PCL-b-PAA in water indicates a densely packed molecular morphology at the water/air interface. Additionally, micelles can be stably formed in the aqueous PCL-b-PAA solution at very low concentrations by demonstrating a low CMC value of 10-4 wt% and a micelle dimension of approximately 30 nm. The model ink dispersion is prepared using organic dyes (Disperse Yellow 232) and the amphiphilic block copolymer of PCL-b-PAA. The dispersion demonstrates near-Newtonian behavior, which is highly favorable for the application as inkjet ink. Furthermore, the ink dispersion displays a low viscosity, making it particularly suitable for visual communication design and printing purposes. Moreover, the ink dispersion demonstrates an unimodal distribution of the particle size, with an average diameter of approximately 500 nm. It retains exceptional stability of dispersion and even conducts a thermal aging treatment at 60 °C for 5 days. This work presents a facile and efficient synthetic strategy and molecular design of AB di-block copolymer-based dispersants for dye dispersions.

Synthesis of vanadium (V) complex with bulky phenoxy ligand and the study of catalysis behavior in ethylene (co)polymerization

A series of imido-vanadium complexes containing bulky aryloxo ligand have been isolated and employed as catalyst in ethylene (co)polymerization. The introduction of bulky ligand in the vanadium complex structure could promote the thermal stability of catalyst in ethylene polymerization. Especially the corresponding catalysts remain good activity in the ethylene copolymerization with polar monomers such as 10-undecen-1-ol (UOH) and methyl 10-undecenoate (UA). In the attempted copolymerization with acrylate monomer, the vanadium catalysts still show moderate activity but only afford polyethylene.

Design, Synthesis, and Spectral Properties of Novel 2-Mercaptobenzothiazole Derivatives.

This paper is focused on the optimalization of methods for the synthesis, isolation, and purification of 2-mercaptobenzothiazole-based acrylic and methacrylic monomers. The structures of the newly synthesized compounds were confirmed through infrared (IR) and nuclear magnetic resonance spectroscopy (NMR). Spectroscopic properties of the resulting 2-mercaptobenzothiazole derivatives were determined based on their absorption spectra and molar absorption coefficients in solvents with varying polarities. A correlation was established between the calculated density functional theory (DFT) energies and Frontier Molecular Orbitals and the experimental observations, confirming their consistency. The practical utility of the synthesized compounds, particularly in future polymerization processes, hinges on a thorough understanding of these properties.

Synthesis and evaluation of a chitosan nanomaterial as efficient sorbent for determination of fungicide residues in waters and wine by liquid chromatography high resolution mass spectrometry.

In the present study a novel, cost-effective, environmentally friendly, and efficient analytical method was developed to analyze fungicide residues in water and wine. The method relies on the application of a newly developed sorbent nanomaterial named Nano-Cs-NAT, synthesized by modifying chitosan, a naturally occurring, low-cost polysaccharide, through grafting with two acrylic monomers and a cross-linker. Nano-Cs-NAT was introduced as analytical sorbent for Dispersive Micro Solid Phase Extraction (D-μ-SPE) before Liquid Chromatography-Orbitrap High-Resolution Mass Spectrometry (LC-Orbitrap HRMS) analysis of twelve fungicides commonly used in viticulture (among the others, triazoles, strobilurines and N-substituted imidazoles). Characterization of the sorbent was conducted, confirming the successful acrylation of chitosan. A multivariate approach was employed to optimize D-μ-SPE extraction parameters. The material was found to be highly effective in simultaneously purifying and concentrating the target analytes, enhancing overall analytical efficiency and sensitivity. The Nano-Cs-NAT-D-μ-SPE-LC-Orbitrap-HRMS method was thoroughly validated, exhibiting good recoveries (72-104%), reproducibility (average RSD ≤ 6%) and repeatability (average RSD ≤ 7%). It also achieved low limits of detection (LOD) in river water (average LOD of 0.04 μg L-1) and wine (average LOD of 0.72 μg kg-1), highlighting its potential for routine fungicide residue analysis. This developed method addresses environmental and food safety concerns by providing an efficient solution for detecting fungicide residues in waters and wine.

Mechanically induced cationic reversible addition-fragmentation chain transfer polymerization of vinyl ethers.

Mechanoredox catalysis has emerged as a sustainable approach for organic transformations. Mechanically controlled polymerization that uses mechanoredox catalysts enables synthesis of complex polymers and mechanoresponsive materials with diverse applications. Despite its potential, the focus has predominantly been on free radical polymerization and acrylate monomers. The mechanochemical synthesis of poly(vinyl ether)s (PVEs) poses a significant challenge in the field. Herein, we report an efficient mechanically induced cationic reversible addition-fragmentation chain transfer (mechano-cRAFT) polymerization using 2D MoS2 as a mechanoredox catalyst, where free radical intermediates can be further oxidized to cations to promote cationic polymerization of vinyl ethers. This mechano-cRAFT polymerization can be conducted in air and with minimal organic solvent, resulting in quantitative monomer conversion. This strategy is applicable to a range of vinyl ether monomers, yielding polymers with controlled molecular weight and narrow dispersity. We also performed trapping experiments to investigate the piezoelectrically mediated redox process, and further validated the mechanism through density functional theory (DFT) calculations.

Monte Carlo optimization based QSAR modeling of the cytotoxicity of acrylic acid-based dental monomers

Acrylic acid derivatives are extensively utilized as initial monomers in dental materials. Nevertheless, these substances exhibit cytotoxicity towards different cell types, a phenomenon that must be reduced in future materials. The primary objective of this research is to establish a QSAR model for the prediction of cytotoxic effects and to identify molecular fragments and descriptors with mechanistic interpretations that play a role in cytotoxic effects. The Monte Carlo optimization technique was employed QSAR models that are not reliant on conformation. These models utilized both molecular graph-based and SMILESbased descriptors. By employing a variety of statistical methodologies, an assessment of the predictive capabilities and resilience of the established QSAR models was achieved. The demonstrated numerical values used for their validation underscore the strong suitability of these QSAR models. The Monte Carlo optimization technique effectively identified molecular fragments represented in QSAR modeling through the use of SMILES notation, elucidating their impact on cytotoxicity, both positively and negatively. Given that the majority of molecular databases adhere to this molecular structure conformation, the featured QSAR models can serve as a rapid and precise screening tool for novel dental monomers.

Synthesis of nucleobase functionalised block copolymers towards precision self-assembly

The formation of nanoaggregates from continuous flow assembly of nucleobase functionalized amphiphilic block co-polymers is investigated.

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.

PH-Sensitive Acrylic Terpolymers for the Coating of Orally Administered Drugs Used for Colonic Release.

Polymeric coatings are a promising option for the development of delivery systems for orally administered drugs. However, the gastrointestinal conditions to which they are subjected, which include low pH and solubility as well as peristaltic movements, can limit their applications. In this work, different formulations of polymeric coatings were produced using pH-sensitive materials consisting of copolymers of methyl acrylate, methyl methacrylate, and methacrylic acid. The polymers were synthesized by the emulsion polymerization technique, obtaining small average particle sizes (56-190 nm), molecular weights between 200,000 and 400,000 g/mol, and a glass transition temperature above 35 °C, which are suitable for film formation at room temperature. Thus, they were assessed as coatings for hydroxypropyl methylcellulose capsules (HPMC) using the immersion method, showing adequate capacity to protect the capsule at gastric pH (pH 1.2) and dissolve at the simulated intestinal pH (pH= 7.2). In particular, the higher the content of the acidic monomer, the higher the release time of the test molecule contained in the acrylic terpolymer-coated HPMC capsules proposed, which was a curcuminoid derivative due to their bright color and potential medical benefits. In addition, a minimum number of immersions was required for coating the HPMC capsules at high acidic concentrations, which further facilitates the delayed release needed for colonic treatment. However, too high proportions of methacrylic acid may result in cytotoxicity issues. Consequently, a biocompatible formulation containing a proportion of methyl acrylate, methyl methacrylate, and methacrylic acid of 7:3:3 is proposed as the most adequate for colonic release. Thus, by chemically modulating the molar percentages of the acrylic monomers, it was possible to obtain tailored acrylic terpolymer coatings with different characteristics and desired properties in order to modulate the release kinetics of an active substance in a colonic environment.

High-Sensitivity Mechanochromic Sensor Using Core-Shell Colloidal Crystals

The Colloidal Crystals-based mechanochromic sensor changes color as the arrangement of colloidal particles changes in response to mechanical deformation, which can be detected through optical measurement. This type of sensor can be used in various applications, such as automobile collision detection, structural deformation detection, and medical equipment, among others. In this study, we prepared a stretchable film by dispersing surface-functionalized colloidal particles in an elastic polymer matrix. Surface of silica colloidal particle was modified with an initiator for Atom Transfer Radical Polymerization (ATRP), followed by surface-initiated ATRP of poly(t-butyl methacrylate) (PtBMA). The core-shell colloidal particles were composited with various acrylic monomers, to fabricate crystalline colloidal array which transforms to elastic film by photopolymerization exhibiting structural color. The prepared film showed a clear color change for deformation within 10%, and the peak reflectance showed more than 30%.

Dual-vat photopolymerization 3D printing of vitrimers

Herein, the processing of multi-material vitrimers with heterogenous properties along their x-,y- and z-axis is demonstrated using dual-vat digital light processing (DLP) 3D printing. The printer is based on a conventional vat exchange set-up containing two vats and a cleaning station, which are positioned on a linearly moving platform, and are exchanged automatically during the layer-by-layer build-up of the object. Two thiol-acrylate resins are selected bearing ample -OH and ester moieties, which undergo thermo-activated transesterification in the presence of an organic phosphate as catalyst. Based on the functionality of the acrylate monomers, printing of multi-material structures with flexible (σ = 1.1 MPa, ε = 14.0%) and rigid (σ = 33.3 MPa, ε = 4.4%) domains is feasible. A good interlayer adhesion between the soft and hard domains is evidenced by uniaxial tensile tests, whilst optical microscopy is used to study the interface. Dynamic mechanical analysis further shows that the stiffness of the photopolymers varies over several orders of magnitude (E’23 °C = 209 kPa - 507 MPa). Jacobs working curves of the two different resins reveal comparable printing parameters at higher exposure doses, which do not only facilitate the printing of multiple materials between individual layers (z-heterogeneity) but also within the same layer (x,y-heterogeneity). This is confirmed by the printing of a multi-material gripper as “proof of concept” demonstrator, which contains soft inner teeth and a stiff outer core. Gripping and releasing of objects is shown by exploiting the glass transition-based shape memory properties of the stiff domains. Moreover, due to the dynamic nature of the covalent bonds, damages inserted into the gripper are intrinsically repairable due to a thermo-activated macroscopic reflow. Shape memory experiments further confirmed that the multi-material gripper fully regains its function after the thermal mending process. Thus, the results clearly show that objects with a high degree of functionality can be realized by combining multi-material 3D printing with the chemistry of vitrimers. This is of particular interest for future soft robotic applications and for mimicking biological composite structures.

A new concept of biocatalytic synthesis of acrylic monomers for obtaining water-soluble acrylic heteropolymers

Rhodococcus strains were designed as model biocatalysts (BCs) for the production of acrylic acid and mixtures of acrylic monomers consisting of acrylamide, acrylic acid, and N-alkylacrylamide (N-isopropylacrylamide). To obtain BC strains, we used, among other approaches, adaptive laboratory evolution (ALE), based on the use of the metabolic pathway of amide utilization. Whole genome sequencing of the strains obtained after ALE, as well as subsequent targeted gene disruption, identified candidate genes for three new amidases that are promising for the development of BCs for the production of acrylic acid from acrylamide. New BCs had two types of amidase activities, acrylamide-hydrolyzing and acrylamide-transferring, and by varying the ratio of these activities in BCs, it is possible to influence the ratio of monomers in the resulting mixtures. Based on these strains, a prototype of a new technological concept for the biocatalytic synthesis of acrylic monomers was developed for the production of water-soluble acrylic heteropolymers containing valuable N-alkylacrylamide units. In addition to the possibility of obtaining mixtures of different compositions, the advantages of the concept are a single starting reagent (acrylamide), more unification of processes (all processes are based on the same type of biocatalyst), and potentially greater safety for personnel and the environment compared to existing chemical technologies.

High-safety lithium metal pouch cells for extreme abuse conditions by implementing flame-retardant perfluorinated gel polymer electrolytes

Lithium metal anodes coupled with nickel-rich cathodes promise high-energy-density batteries. Nonetheless, the overall safety of lithium metal batteries is compromised by the use of conventional thermally unstable and flammable carbonate-based electrolytes, which hinders their practical applications, especially under abuse conditions. Herein, a flame-retardant perfluorinated gel polymer electrolyte (PFGPE) is developed by in situ copolymerization of perfluorobutyl acrylate (PFBA) monomer with pentaerythritol tetraacrylate (PETEA) crosslinker. PFBA decomposes at high temperatures to generate fluorine radicals that eliminate hydrogen and hydroxyl radical chain combustion reactions in the gas phase, reducing the combustion risk of electrolytes. Additionally, the co-pyrolysis of the carbonate-based electrolytes and the copolymerization matrix produces a P- and F- containing char layer in the condensed phase, blocking the heat and oxygen required for combustion. A large-format PFGPE modified Li metal pouch cell (4.4 Ah, 381 Wh kg−1) achieves 120 cycles with 83.4% of capacity retention under a lean electrolyte of 3 g Ah−1 and a negative/positive capacity ratio of 1.82. Moreover, the modified pouch cell exhibits enhanced thermal safety characteristics and passes international standard tests (GB/T 31485–2015) for mechanical nail penetration and thermal abuse. This innovative approach represents a significant milestone towards the advancement of high-safety Li metal batteries.

3D-printable hydrophobic silicone inks for antiadhesion tough objects via molecular engineering

3D printable hydrophobic ink is highly desirable to simply print hydrophobic objects for various applications, such as oil/water separation. However, printable hydrophobic monomers/inks are limited which seriously restricts the fabrication and application of 3D printing hydrophobic objects. Herein, simulating the crown, trunk, and roots of trees from the molecular levels, coatings/objects were designed and prepared using a 6-functional hyperbranching polyurethane acrylate (PUA) monomer as the “trunk”, mono-acrylate terminated polydimethylsiloxane (Vi-PDMS) as the “leaf”, and tripropylene glycol diacrylate (TPGDA) as the “root”. The printed objects with excellent mechanical properties and stable hydrophobicity with CAs and SAs in the range of 80°–110° and 10°–30°, respectively, and could be used in a variety of environments (e.g., acid-based solution, seawater) for a month. Cylindrical, ladder, and mushroom-shaped micro-nano structures could be prepared to improve the hydrophobicity of the printed objects to achieve CAs up to ∼170°. The antiadhesion tough teeth and microchannels could be prepared facilely with the hydrophobic inks. This work demonstrates a simple and rapid method to manufacture various complex and sophisticated hydrophobic coatings/objects and a broader strategy for 3D printing technology.

Fabrication of a Novel Fluorescein Embedded Photocomposite Based on Interpenetrating Polymer Network (IPN) and Its Application in 4D Printing

AbstractWith the rapid development of the 3D printing technique, the concept of 4D has emerged, defining time as the fourth dimension. This concept allows for changes in the appearance, function, or other properties of 3D printed objects in response to certain controlled external stimuli over time. In this work, a new photocomposite containing fluorescein based is designed on an interpenetrating polymer network (IPN) system, this system can be generated by the simultaneous photopolymerization of acrylate and epoxide monomers under visible LED@405 nm irradiation. Unexpectedly, combining the reversible fluorometric turn‐on property of fluorescein and the deformation of the IPN in the presence of water, the 3D flower structure printed from this photocomposite would demonstrate a novel dual responsive behavior with both fluorescence and shape changes when it is exposed to water for a short time. This work would present a novel functional photocomposite material and also expand the application prospect of 4D printing.

Photoinitiator-grafted polymer coating enable various hydrogels with strong resistance to both drying and swelling

Currently, diverse hydrogels with multiple functionalities have attracted considerable attention. However, due to poor adaptability in real-life application scenarios for example in drying air and underwater, the hydrogels developed to date have not yet realized most of their promising applications, particularly in flexible electronics. Herein, inspired by the process of preparing the outermost layer of sugar coating on Tanghulu, a traditional Chinese winter snack, we report a dipping-ultraviolet (UV) encapsulation method for affording hydrogels with excellent water retention and anti-swelling capacity. A photoinitiator-grafted polymer chain (PGPC) with UV curing capability is prepared by 4-benzoylphenyl acrylate (ABP) and hydrophobic monomers radical polymerization, which is uncrosslinked during synthesis. After dipping and UV irradiation, the PGPC on the polyacrylamide (PAAm) hydrogel surface is cross-linked by benzophenone (BP) chemistry to form a coating network. Furthermore, the PGPC-coated hydrogel PAAm demonstrates great anti-drying properties with a weight fraction of up to 0.85 ± 0.02 after 21 h at 50 °C and anti-swelling capacity with a weight fraction of down to 1.01 ± 0.01 after 120 h in deionized water. Benefiting from the BP chemistry, the versatility of this method is demonstrated using various hydrogels such as polyvinyl alcohol (PVA) and polyzwitterionic hydrogel. As a proof-of-concept, the coated-hydrogel-based sensor shows strong signals anti-interference ability in ambient air and underwater. This work provides a promising route for encapsulating different hydrogels endowing weak hydrogels with strong environmental adaptability.

Triphenylamine-substituted BODIPY dye based photoinitiators for free radical and cationic photopolymerization under visible LED irradiation and application in 3D printing

Until now the photopolymerization process is largely dependent on the hazardous UV or near UV light irradiation. Herein this work, a series of boron dipyrromethene (BODIPY) derivatives substituted by electron-donating triphenylamine moiety on different positions were introduced and investigated thoroughly. Markedly, their photoinitiation abilities under mild conditions, e.g. visible LEDs irradiation and room temperature, were examined for the first time. In combination with an iodonium salt and an amine as the co-initiators, these BODIPY dyes could form three-component photoinitiating systems (PISs) for the purpose to initiate both the free radical polymerization of acrylate monomers and cationic polymerization of epoxy monomers. Interestingly, under the irradiation of LED@405 nm, LED@530 nm or LED@660 nm, some of these BODIPYs-based PISs could conduct high monomeric conversion and rapid photopolymerization rates, as reflected by the relevant photopolymerization kinetics. Then the notable photochemical reactivity of these BODIPY dyes was examined by both steady state photolysis and fluorescence quenching experiments, and theoretical calculation was also performed on them in details. Finally, photocuring 3D printing technique was applied to the acrylate/epoxy mixture resin, as the result the BODIPYs-based PISs demonstrated great potential to fabricate truly three-dimensional objects in macroscopic scale with excellent spatial resolution.