Coumarin-Based Oxime Esters: Photobleachable and Versatile Unimolecular Initiators for Acrylate and Thiol-Based Click Photopolymerization under Visible Light-Emitting Diode Light Irradiation

Developing efficient unimolecular visible light-emitting diode (LED) light photoinitiators (PIs) with photobleaching capability, which are essential for various biomedical applications and photopolymerization of thick materials, remains a great challenge. Herein, we demonstrate the synthesis of a series of novel PIs, containing coumarin moieties as chromophores and oxime ester groups as initiation functionalities and explore their structure–activity relationship. The investigated oxime esters can effectively induce acrylates and thiol-based click photopolymerization under 450 nm visible LED light irradiation. The initiator <b>O-3</b> exhibited excellent photobleaching capability and enabled photopolymerization of thick materials (∼4.8 mm). The efficient unimolecular photobleachable initiators show great potential in dental materials and 3D printings

Structural Design Strategy of a Biobased Allyl Compound with Dynamic Boronic Ester Bonds to Form Rigid-Soft Self-Healing Polymer Networks via Thiol–Ene “Click” Photopolymerization for Integrated Preparation of a Flexible Device

Fabricating biobased flexible polymers with high toughness and self-healing ability will promote sustainable development of the fast-growing flexible electronic industry. Herein, a biobased allyl compound (BAMDB) with boronic ester bonds was synthesized from renewable eugenol and then combined with multifunctional thiol via thiol–ene “click” photopolymerization to form a series of flexible networks (BAMDB-SH). Their integrated performance, including thermal, optical, and mechanical properties as well as self-healing behavior, was studied. Their glass transition temperature ranged from 42 to 55 °C and showed high transparency (88.2–89.3% at 550 nm). At the same time, BAMDB-SH3 has the most excellent comprehensive mechanical properties with a tensile strength, an elongation at break, and a toughness of 29.8 MPa, 194.3%, and 35.3 MJ m–3, respectively, owing to its rigid-soft network structure with appropriate cross-linking density. Depending on the dynamic exchange of boronic ester bonds, BAMDB-SH3 networks could be healed in 30 min at 80 °C with a high self-healing efficiency of 98%. In addition, based on the excellent comprehensive performance and self-healing properties of BAMDB-SH3, it was used to prepare a sandwich sensor by integrated encapsulation of silver nanowires for wrist activity detection, demonstrating the potential applications of BAMDB-SH in flexible devices

One-Step Solvothermal Synthesis of Petalous Carbon-Coated Cu⁺‑Doped CdS Nanocomposites with Enhanced Photocatalytic Hydrogen Production

Metal ion doping and nanocoating a CdS photocatalyst have been proven to be effective strategies to inhibit photocorrosion and improve photocatalytic performance. In this study, carbon-coated Cu⁺-doped CdS nanocomposites (C-Cu-CdS) with a stable petalous structure and highly uniform size distribution were successfully synthesized via a facile one-step solvothermal method. Both Cu⁺ doping and carbon coating to the CdS photocatalyst are realized in this one-step strategy. Benefiting from the unique core–shell structure and metal ion doping, the as-prepared C-Cu-CdS catalyst exhibits significantly enhanced photostability and visible-light-driven photocatalytic efficiency. For an optimal Cu⁺ doping percentage of 1.0%, an average hydrogen production rate of 2796 μmol h^–1 g^–1 and an apparent quantum efficiency of 16.0% at a wavelength of 420 nm was observed, the latter of which is nearly 9.3 times higher than that of the carbon-coated CdS product without Cu⁺ doping. The origin of the improved photocatalytic activity is systematically investigated by examining the effects of Cu⁺ doping

Tannic Acid Induced Self-Assembly of Three-Dimensional Graphene with Good Adsorption and Antibacterial Properties

In this paper, a green one-step strategy is developed to fabricate three-dimensional (3D) graphene-based multifunctional material with the aid of tannic acid. Tannic acid (TA), a typical plant polyphenol widely present in woods, reduced GO and induced the self-assembly of reduced graphene oxide into graphene hydrogel. The preparation process was carried out in aqueous media under atmosphere pressure without using any toxic reducing agent or special instrument, which is a facile, green, and low-cost method. The as-prepared monolithic 3D graphene exhibits high porosity, low density, hydrophobicity, good mechanical performance, and thermal stability. In addition, it shows excellent adsorption toward dyes, oils, and organic solvent, which should be a promising candidate for efficient adsorbents in water purification. Moreover, the tannic acid retained in the skeleton of 3D graphene functions as a biofunctional component, which endows the TA-GH with good antibacterial capability

Novel Star Polymers as Chemically Amplified Positive-Tone Photoresists for KrF Lithography Applications

Xanthate-mediated reversible addition–fragmentation chain transfer (RAFT) methodologies have been applicable to preparation of branched or star polymers. In this article, novel star copolymers have been synthesized through xanthate-mediated RAFT polymerization with <i>p</i>-acetoxystyrene and <i>tert</i>-butyl acrylate. Fourier transfer infrared, nuclear magnetic resonance spectra, and gas chromatography analyses indicated that the polymerization was successful between both of the monomers and the star RAFT agent. The intrinsic viscosity and Zimm branching factor (<i>g</i>′) were used to confirm the copolymers’ architecture. The ultraviolet absorbance of the copolymer solutions indicated that the copolymer was suitable for use as a krypton fluoride (KrF) laser photoresist. Moreover, the photolithography performance of the positive-tone chemically amplified photoresist was evaluated. The results indicated that the photosensitive based on the star copolymer was higher than the linear one, and the pattern resolution was around 200 nm at a low exposure energy

UV-Curable Coatings from Multiarmed Cardanol-Based Acrylate Oligomers

Multiarmed, cardanol-based acrylate oligomers were prepared via the ring-opening reaction between cardanyl glycidyl ether (CGE) and polyacids, followed by epoxidization of the unsaturation in alkyl side chains of cardanol segments, and acrylation of the resulting epoxy groups. Biobased coatings were produced from UV-radiation-initiated curing of these acrylates; the coating properties were then characterized in detail. The acrylate oligomers were fully characterized using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance (¹H NMR). The UV-curing behavior of these acrylates was determined using real-time IR. The results indicated that the conversion of acrylate unsaturation increased with increasing oligomer functionality. These oligomers were formulated into UV-curable coatings, and the coating properties were evaluated to determine hardness, adhesion, chemical resistance, gloss, and surface properties. The properties of cured thermosets were also studied using tensile testing, dynamic mechanical thermal analysis (DMTA), and thermogravimetric analysis (TGA). Compared to coating from benchmark biobased UV-curable oligomer, acrylated epoxidized soybean oil (ASBO), cardanol-based coatings showed higher hardness, excellent adhesion, and enhanced thermal and mechanical properties while maintaining reasonably high biorenewable contents. These improvements in coating performances can be contributed to their unique oligomer architectures that combined the structural features of rigid benzene ring, long flexible alkyl chains, and polar hydroxyl groups

Synthesis of Water-Dispersible Molecularly Imprinted Electroactive Nanoparticles for the Sensitive and Selective Paracetamol Detection

A novel kind of water-dispersible molecularly imprinted electroactive nanoparticles was prepared combining macromolecular self-assembly with molecularly imprinting technique employing paracetamol (PCM) as template molecule. An amphiphilic electroactive copolymer (P­(NVC-EHA-AA), PNEA) containing carbazole group was first synthesized through a one-pot free radical copolymerization. The coassembly of the electroactive copolymers with the template molecules (PCM) in aqueous solution generated nanoparticles embedded with PCM, leading to the formation of molecularly imprinted electroactive nanoparticles (MIENPs). A robust MIP film was formed on the surface of electrode by electrodeposition of MIENPs and subsequent electropolymerization of the carbazole units in MIENPs. After the extraction of PCM molecules, a MIP sensor was successfully constructed. It should be noted that electropolymerization of the electroactive units in MIENPs creates cross-conjugated polymer network, which not only locks the recognition sites but also significantly accelerates the electron transfer and thus enhances the response signal of the MIP sensor. These advantages endowed the MIP sensor with good selectivity and high sensitivity for PCM detection. The MIP sensor could recognize PCM from its possible interfering substances with good selectivity. Under the optimal conditions, two linear ranges from 1 μM to 0.1 mM and 0.1 to 10 mM with a detection limit of 0.3 μM were obtained for PCM detection. The MIP sensor also showed good stability and repeatability, which has been successfully used to analyze PCM in tablets and human urine samples with satisfactory results

Image_1_Polyvinyl alcohol film with chlorine dioxide microcapsules can be used for blueberry preservation by slow-release of chlorine dioxide gas.TIF

IntroductionChlorine dioxide (ClO2) is a safe and efficient bactericide with unique advantages in reducing foodborne illnesses, inhibiting microbial growth, and maintaining the nutritional quality of food. However, gaseous ClO2 is sensitive to heat, vibration, and light, which limits its application.MethodsIn this study, a ClO2 precursor-stabilized ClO2 aqueous solution was encapsulated by the double emulsion method, and a high-performance ClO2 self-releasing polyvinyl alcohol (PVA) film was prepared to investigate its performance and effect on blueberry quality during storage.ResultsThe self-releasing films had the best overall performance when the microcapsule content was 10% as the film's mechanical properties, thermal stability, and film barrier properties were significantly improved. The inhibition rates of Listeria monocytogenes and Escherichia coli were 93.69% and 95.55%, respectively, and the mycelial growth of Staphylococcus griseus was successfully inhibited. The resulting ClO2 self-releasing films were used for blueberry preservation, and an experimental study found that the ClO2 self-releasing antimicrobial film group delayed the quality decline of blueberries. During the 14-day storage period, no mold contamination was observed in the ClO2 self-releasing film group, and blueberries in the antibacterial film group had higher anthocyanin accumulation during the storage period.DiscussionResearch analysis showed that films containing ClO2 microcapsules are promising materials for future fruit and vegetable packaging.</p

Enhancing Lignin Model Compound Depolymerization Using Mediator-Enzyme Catalysis: A Sustainable Approach to C–C Bond Cleavage

The effective cleavage of C–C/C–O bonds in linkages of lignin with mild conditions and a green process was still a huge challenge for lignin valorization. Herein, the mediator–enzyme systems utilized in the depolymerization of lignin were developed. The C–C oxidation of β-O-4 lignin models was achieved through a mediator–enzyme systems. The carboxylic acid/ester-lipase was employed for the oxidation of ketone compounds. In the C–C bond oxidation process, Novozym 435 was used as the catalyst, and H2O2 was used as the oxidant in the solvent of ethyl acetate for the reaction. The reaction conditions were optimized, and excellent conversion was achieved. The mediator-enzyme was active for the oxidative cleavages of various β-O-4 lignin model compounds substituted by different functional groups. Furthermore, Novozym 435 was employed as a recyclable biocatalyst, demonstrating its stability confirmed by SEM, FTIR, and XPS. This study introduces a mediator-enzyme strategy for lignin model compound depolymerization

Knock down of androgen receptor variants regulates AR transcriptional activity in Pten deficient murine prostate cancer cell lines.

<p><b>a)</b> E8 cells were transfected with siRNAs targeting either mAR-Va or c and evaluated for PSA-luc reporter activity 48 hours later (control siRNA <i>vs</i>. mAR-Va siRNA = comparisons 1–3; control siRNA <i>vs</i>. mAR-Vc siRNA = comparisons 4–7). b) Validation of siRNA knockdown of mAR-Vc as measured by q-PCR (*, p<0.05, **, p<0.01).</p