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The application of conventional absorbing materials is limited due to complex preparation process and poor transparency caused by fillers. In this study, a highly transparent ionic ...organogel was prepared by photocuring a dimethyl sulfoxide (DMSO) solution of a polymerizable magnetic cationic monomer DAC5Dy(NCS)8. Both components of organogel, which are the photopolymerizable magnetic cationic monomer and polar solvent DMSO, have an important effect on the magnetic losses and dielectric losses properties of the organogel respectively. By tuning the mass ratio of DMSO to the monomer and the content of the cross-linker, the complex permittivity of the gel could be effectively adjusted to improve the impedance matching, and finally a gel with excellent wave absorption properties and good tensile properties was obtained. The optimum organogel was fabricated with a minimum reflection loss of −45.9 dB and a broadest effective absorption bandwidth (EAB) of up to 5.2 GHz, and effective absorption in the millimeter band (26.5–40 GHz) which is within the fifth generation (5G) mobile networks. With the advantages of simple preparation method, arbitrary shape and good adhesion to a variety of substrates and complex surfaces, this multifunctional gel provides a new solution for complex scenarios requiring optical transparency and simultaneous absorption of electromagnetic waves.
Recently, flexible strain sensors have been intensively studied in order to meet the growing demands of detecting multiscale mechanical deformations. However, it remains a big challenge to integrate ...high stretchability and high sensitivity in a strain sensor simultaneously. In this study, a highly stretchable and sensitive strain sensor is successfully fabricated by constructing ionogel/silver synergistic conductive network. The transmetalation reaction is utilized to transform the copper atoms in the copper/ionogel nanocomposite into more silver atoms with larger radius, which eliminates the interspace among the nanoparticles, and therefore a silver/ionogel nanocomposite with high conductivity is obtained. Owing to the fragility of the conductive network, the obtained nanocomposite possesses high sensitivity. In addition, as the polymer substrate, the conductive ionogel can connect the crack of the silver conductive network during stretching, endowing the nanocomposite with high stretchability. Hence, the obtained strain sensor exhibits a high sensitivity in a wide sensing range and can detect various human activities. Therefore, this strategy can be envisioned as promising strategy for fabricating high‐performance strain sensors and other flexible electronics.
A nanocomposite‐based strain sensor with Ag/ionogel synergistic conductive network is prepared by constructing copper–silver transmetalation reaction in ionogel. The obtained strain sensor possesses both high sensitivity and high stretchability, and can detect different mechanical deformation, such as human joint motions and pulse.
We synthesized silver nanoplates using the solvothermal method and, for the first time, placed them as crystal seeds in a water-based growth solution, thereby successfully achieving the large-scale ...production of silver nanoplates. The synthesis method enabled independent control of the lateral size and vertical size of the silver nanoplates. More specifically, the lateral size could be adjusted within the range of 565 nm–1.682 μm, while the vertical size was achieved by introducing Cl– as a capping agent and the vertical size was thickened from 18.28 to 40.41 nm.
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•The effect of four substituents on the light absorption and photoinitiating ability of chalcone was investigated.•Aldehyde side substitution structure has a strong influence on ...chalcone initiation properties.•The potential for deep curing of the C4S/TEOA system under 405 nm LED lamp was explored.
Chalcones (Chals) are considered as attractive photoinitiators due to their large-scale conjugated structure and the ease of modification to the substituent structure on both sides. However, there is still a lack of full understanding as to the effects of substituents and their positions on the photophysical and photochemical properties and initiation efficiency of chalcones. In the present study, eight types of chalcone were designed and synthesized from the aromatic aldehydes and ketones containing four different substituents through para-substitution. These chalcones exhibit varying degrees of absorption in the visible region, and their maximum absorption wavelength increasing with the electron donating ability of the substituents when the substituents are positioned on the same side. At the aldehyde side, substitution exerts a more significant effect on their absorption when the substituents are identical. According to photopolymerization and steady-state photolysis, C4S performs best in the efficiency of photochemical hydrogen atom transfer, which leads to the high polymerization efficiency. Furthermore, it shows a great potential for use in the deep curing and curing of light-colored materials due to the lighter color of C4S and its smaller visible light absorption.
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•The photophysical and electrochemical properties of ANDs were characterized.•Effects of electronic group of sensitizers on photopolymerization were summarized.•DFT calculations were ...carried out to study the PET process.
Dyes with D-A structure bearing electron donor (ED) and electron withdrawing (EW) moieties were widely adopted in photosensitized polymerization. However, the individual functions of ED and EW groups were rarely discussed. In this work, anthracene derivatives (ANDs) possessing aldehyde (ANCHO) and methoxy group (ANOCH3) at 9-position were carried out as photosensitizers for ONI. Photopolymerization and photobleaching results indicate that ANOCH3/ONI presents higher sensitizing performance than that of anthracene, while ANCHO presents no sensitizing ability although the calculated free energy change of photoinduced electron transfer (PET) reaction of ANCHO/ONI is also negative. To disclose the electronic effect of substitution on PET reaction, experiments and theoretical calculation were jointly employed. Cyclic voltammetry result indicates the EW group aldehyde makes the ANCHO hard to be oxidized. Moreover, the intermolecular charge transfer property of ANCHO hampers the formation of stable ANCHO-ONI complex. On the contrary, the ED group methoxy not only decreases the oxidation potential of ANOCH3, but also further stabilizes the ground ANOCH3-ONI complex, which was considered to be responsible for its enhanced sensitizing ability.
Four ferrocene-based D-π-A dyes with effective intramolecular charge transfer (ICT) properties are designed and synthesized. These dyes can be used as new photoredox catalysts in free radical ...photopolymerization under soft blue and green LED irradiations. Different π-conjugation bridge molecules contained in the molecular structures have been shown to affect the photoreactivities of the synthesized dyes in the photoinitiating systems. The UV–Vis absorption, electrochemical, and third-order nonlinear optical properties are investigated. Experimental results are completed with theoretical calculations to gain further insight into the ICT of the dyes with different π-conjugation bridge molecules. A good correlation of the π-conjugation bridge molecule changes of the dyes with the experimental results is established.
Ferrocene based D-π-A dyes as novel photoredox catalysts in photopolymeization under soft visible LED irradiations. Display omitted
•Four ferrocene-indanone organometallic dyes are designed and synthesized.•The dyes exhibit effective ICT characters and show good nonlinear absorption properties.•A good correlation of experimental and theoretical results is established.•The dyes can be used as photoredox catalysts in photopolymerization under LED irradiations.
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•A Schiff base (BPN) containing benzophenone and dimethylamine group was facilely synthesized.•BPN shows good absorption ability in 300 nm ∼ 500 nm.•Visible light (405/460 nm) induced ...radical polymerization was achieved by using BPN as photoinitiator.•BPN could act as one-component photoinitiator.
Prolongation of the absorption wavelength of photoinitiator is very important issue but often suffered from tedious synthesis and purification procedures. In this work, by one spot Schiff base condensation of 4-anmino-benzophenone and 4-(dimethylamino)-2-hydroxybenzaldehyde, a benzophenone incorporated Schiff base ligand BPN was prepared. The structure of BPN was well characterized by spectroscopy technology. BPN shows strong absorption among the wavelength of 400 ∼ 500 nm. The initiation efficiency of BPN toward an acrylate monomer under 405/460 nm LED was evaluated by real-time FT-IR technology. The photoreaction between BPN and co-initiator was studied by steady state photolysis, fluorescence quenching, electron spin resonance spin trapping, nano-second transient absorption and cyclic voltammetry techniques. The results showed that BPN had strong interaction with amine co-initiator. This work proves that BPN is an excellent visible light photoinitiator and Schiff base condensation is a reliable way to design novel photoinitiator.
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•The acidochromism of C3PY in different solvents and solid-state were investigated.•The dielectric constant and basicity of solvent influence the acidochromism behavior.•A general ...mechanism for acidochromism was proposed.•The application of C3PY as acid sensor was explored.
Molecules with stimulus-response properties have always been a research hotspot. However, the acidochromism of enone dyes was rarely studied. In this work, the solvatochromism of an N-methyl pyrrole-based enone dye (C3PY) in nine organic solvents was firstly investigated by Kamlet–Taft equations. Then, with trifluoroacetic acid (TFA) as an example, the acidochromism of C3PY was investigated in nine solvents and solid state. Different acidochromism behaviors were observed and analyzed, which were discussed in terms of the solvent properties such as dielectric constant and basicity. A general mechanism was proposed and was supported by the 1H NMR acid titration experiments. Finally, the reversibility of acidochromism was evaluated and the application of C3PY as a TFA sensor was explored.
Recently, the preparation of polymeric membranes by UV-induced polymerization is encouraged due to the ultrafast curing and controllable operation. However, the long-period exposure under UV light ...has a great threat to both the environment and operators. Herein, we developed the visible-light-induced polymerized PDMS membrane for the pervaporative separation of furfural. The differences among photoinitiator ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate (TPO-L), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) and 2-hydroxy-2-methylpropiophenone (1173) in the polymerization kinetics, membrane structure and separation performance are compared. Results show that the absorbance of TPO-L matches 405 nm of the visible light region; and it can be well dispersed and compatible with PDMS and obtain high initiation efficiency. Furthermore, the conditions including TPO-L concentration and PDMS viscosity are optimized, and the prepared membrane has an outstanding pervaporation performance containing 1299.5 g m−2 h−1 of total flux and 40.2 of furfural separation factor. Importantly, the ultrafast and continuous preparation process of membrane is operated by a home-made machine, indicating the wonderful potential for its large-scale application.
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•Fast preparation of PDMS membrane induced by visible light.•Avoiding the harm of UV light to environment and operators by using visible light.•Visible photoinitiator TPO-L shows a high initiation efficiency.•A 1299.5 g m−2 h−1 of total flux and 40.2 of furfural separation factor are obtained.•Continuous preparation process of membrane is operated by a home-made machine.
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•Three enone dyes (C3s) bearing N-alkylated pyrrole, indole, and carbazole group were synthesized.•Photophysical and electrochemical properties of C3s were obtained.•The photon ...initiation ability of C3s with or without tertiary amine were investigated.•The different initiation performance of C3s were explained.
In this work, three enone dyes (C3s) bearing N-alkylated pyrrole (C3PY), indole (C3ID) and carbazole (C3CZ) group were synthesized and characterized to explore the effect of peripheral group on their photoinitiation ability. C3s display good light absorption in the region of 300–500 nm. Under 405/460 nm LED irradiation, the polymerization kinetics of a diacrylate monomer in the presence of one-component C3s or bimolecular C3s/triethanolamine (TEOA) were investigated by Real-time FT-IR technology. Polymerization profiles show that C3s could initiate the polymerization and TEOA significantly promote the initiation efficiency of C3CZ, while this acceleration effect is relatively small for C3PY and C3ID. To decipher these phenomenon, steady state photolysis, cyclic voltammetry and theoretical calculation were jointly performed. Accordingly, it is proposed that C3PY and C3ID tend to photolyze through intramolecular hydrogen abstraction. This work show that the peripheral group strongly affect the initiation ability of enone photoinitiator.
