Oxidative Polymerization Reaction Research Articles

Fabrication of core–shell nickel ferrite@polypyrrole composite for broadband and efficient electromagnetic wave absorption

Herein, nickel ferrite@polypyrrole (NiFe2O4@PPy) composite was prepared by a simple two-step route of solvothermal synthesis and in-situ oxidation polymerization reaction. The results of micromorphology analysis showed that the obtained NiFe2O4@PPy composite had a unique core–shell structure, good magnetic performance and electrical conductivity. Furthermore, the as-prepared magnetic/conductive NiFe2O4@PPy composite exhibited notably enhanced electromagnetic wave (EMW) absorption performance than pure NiFe2O4 and PPy. When the filling ratio was 17.5 wt% and the matching thickness was 2.24 mm, the optimal minimum reflection loss (RLmin) of −56.25 dB and a broad effective absorption bandwidth (EAB) of 5.2 GHz were achieved for NiFe2O4@PPy composite. With slightly increasing the matching thickness to 2.6 mm, the maximum EAB of 7.12 GHz could be reached. Additionally, the probable EMW absorption mechanism was elucidated. Therefore, this work could provide a valuable reference for the preparation of magnetic ferrite/conductive polymer composites as broadband and high-efficiency EMW absorbers.

Fabrication of a reusable carbon quantum dots (CQDs) modified nanocomposite with enhanced visible light photocatalytic activity

In awareness of industrial dye wastewater, carbon quantum dots (CQDs) and cobalt zinc ferrite (CZF) nanocomposites were synthesised for the making of carbon quantum dots coated cobalt zinc ferrite (CZF@CQDs) nanophotocatalyst using oxidative polymerization reaction. The results of TEM, zeta potential value, and FTIR confirm highly dispersed 1–4 nm particles with the − 45.7 mV carboxylic functionalized surface of CQDs. The results of the synthesised CZF@CQDs photocatalyst showed an average particle size of ~ 15 nm according to TEM, SEM, and XRD. The photocatalyst showed a 1.20 eV band gap, which followed the perfect visible light irradiation. TGA and DTA revealed the good thermal stability of the nanophotocatalyst. VSM was carried out, and the saturation magnetisations for CZF and CZF@CQDs were 42.44 and 36.14 emu/g, respectively. A multipoint study determined the BET-specific surface area of the CZF@CQDs photocatalyst to be 149.87 m2/g. Under visible light irradiation, the final CZF@CQDs nanophotocatalyst demonstrated remarkable efficiency (~ 95% within 25 min) in the photocatalytic destruction of Reactive Blue 222 (RB 222) and Reactive Yellow 145 (RY 145) dyes, as well as mechanical stability and recyclability. Even after the recycling of the degradation study, the nanophotocatalyst efficiency (~ 82%, 7th cycles) was predominantly maintained. The effects of several parameters were also investigated, including initial dye concentration, nanophotocatalyst concentration, CQD content, initial pH of the dye solution, and reaction kinetics. Degradation study data follow the first-order reaction rate (R2 > 0.93). Finally, a simple and low-cost synthesis approach, rapid degradation, and outstanding stability of the CQD-coated CZF nanophotocatalyst should make it a potential photocatalyst for dye wastewater treatment.

Conjugated diacetylene polymers with intrachain D-A block heterostructure for efficient photocatalytic hydrogen production

Solar-driven photocatalytic hydrogen production has been considered as a promising candidate technology for supplying green and sustainable energy source alternative to fossils. But its low solar-to-hydrogen conversion efficiency level hampers its practical application, and lack of effective structure for promoting charge separation is one of the accounts. Herein, intrachain heterojunction structure comprised of donor-acceptor (D-A) blocks has been proved to be one of effective structures for addressing such an issue. Utilizing the facile oxidative coupling polymerization reactions of diacetylene monomers and oligomers, a block heterojunction polymeric photocatalyst named PDTPDPA-BP bearing D-A blocked heterostructure was synthesized by first separative oligomerizations of diacetylene-functionalized dibenzothiophene sulfone (DTP) and triphenylamine (TPA) monomers and then mixed together and undergoing further polymerization. In photocatalytic hydrogen production, PDTPDPA-BP displayed a hydrogen evolution rate of 2164 μmol g−1 h−1, which is much larger than those of PDTP (1270 μmol g−1 h−1) and PTPA (57 μmol g−1 h−1) synthesized by homopolymerization of DTP and TPA monomers, respectively, and their 1:1 molar ratio physical blend (363 μmol g−1 h−1). By means of Fluorescence spectroscopy and photo-responsive measurements, it was found PDTPDPA-BP has narrower bandgap and more efficient charge separation than the other polymers. Therefore, the work highlights intrachain heterojunction structure promotes exciton dissociation into free charge carries, and thus deserves the consideration in the design of high performance organic photocatalysts.

Poly-3,4-dihydroxybenzylidenhydrazine, a different analogue of polydopamine

Abstract In this article, 3,4-dihydroybenzylidenehydrazine is synthesized for the first time, and its properties as a dopamine analogue for polymerization are investigated. Using an oxidative polymerization reaction, the reaction mechanism as well as the coating ability of the new polymer is determined and compared to that of polydopamine. The polymerization reactions were performed in a mixture of methanol–water with NaIO4 as an oxidation reagent. The polymer was used as a coating on both glass surfaces with a thickness of ∼5 nm as determined by AFM, as well as on TiO2 nanoparticles. For the latter, SEM/TEM and the pH-dependent variation of zeta potential were measured. As a free polymer, poly-3,4-dihydroxybenzylidenhydrazine was investigated by UV-Vis, ss-NMR, and FTIR, and a variety of monomeric units were found in the polymer matrix. The solubility in methanol or DMSO of the monomer and the slight solubility of the polymer allowed us to study the fluorescence and cyclic voltammetry properties for both the monomer and polymer.

Designing hard carbon microsphere structure via halogenation amination and oxidative polymerization reactions for sodium ion insertion mechanism investigation

Hard carbon as a negative electrode material for sodium-ion batteries (SIBs) has great commercial potential and has been widely studied. The sodium-ion intercalation in graphite domains and the filling of closed pores in the low voltage platform region still remain a subject of controversy. We have successfully constructed hard carbon materials with a pseudo-graphitic structure by using polymerizable p-phenylenediamine and dichloromethane as carbon sources. This was achieved by a halogenated amination reaction and oxidative polymerization. It was found that the capacity of hard carbon materials mainly originates from intercalation into graphite domains. The study found that the prepared hard carbon could store 339.33 mAh g−1 of sodium in a reversible way at a current density of 25 mA g−1, and it had an initial coulomb efficiency of 80.23%. It even maintained a reversible sodium storage capacity of 125.53 mAh g−1 at a high current density of 12.8 A g−1. Based on the analysis of hard carbon structure and electrochemical performance, it was shown that the materials conform with an “adsorption-intercalation” mechanism for sodium storage.

The Effects of Structure and Oxidative Polymerization on Antioxidant Activity of Catechins and Polymers.

Polyphenols are key free radical scavengers in tea. This study screened the antioxidant active groups of catechins and dimers and analyzed the effects of the degree of oxidative polymerization and oxidative dimerization reaction on their antioxidant activities. ABTS+· free radical scavenging activity, DPPH free radical scavenging activity, and total antioxidant capacity of catechins and polymers were systematically analyzed and compared in this study. Results manifested antioxidant activities of catechins were dominated by B-ring pyrogallol and 3-galloyl, but were not decided by geometrical isomerism. 3-galloyl had a stronger antioxidant activity than B-ring pyrogallol in catechins. The number, not the position, of the galloyl group was positively correlated with the antioxidant activities of theaflavins. Theasinensin A has more active groups than (-)-epigallocatechin gallate and theaflavin-3,3'-digallate, so it had a stronger antioxidant activity. Additionally, the higher the degree of oxidation polymerization, the weaker the antioxidant activities of the samples. The oxidative dimerization reaction hindered the antioxidant activities of the substrate-catechin mixture by reducing the number of active groups of the substrate and increasing the molecular structure size of the product. Overall, pyrogallol and galloyl groups were antioxidant active groups. The degree of oxidative polymerization and the oxidative dimerization reaction weakened the antioxidant activity.

Copper nanoparticles/polyaniline/molybdenum disulfide composite as a nonenzymatic electrochemical glucose sensor

A Cu@Pani/MoS2 nanocomposite was successfully synthesized via combined in-situ oxidative polymerization and hydrothermal reaction and applied to an electrochemical nonenzymatic glucose sensor. The morphology of the prepared Cu@Pani/MoS2 nanocomposite was characterized using FE-SEM and Cs-STEM, and electrochemical analysis was performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry techniques. Electrostatic interaction between Cu@Pani and MoS2 greatly enhanced the charge dispersion, electrical conductivity, and stability, resulting in excellent electrochemical performance. The Cu@Pani/MoS2 was used as an electrocatalyst to detect glucose in an alkaline medium. The proposed glucose sensor exhibited a sensitivity, detection limit, and wide linear range of 69.82 μAmM−1cm−2, 1.78 μM, and 0.1–11 mM, respectively. The stability and selectivity of the Cu@Pani/MoS2 composite for glucose compared to that of the potential interfering species, as well as its ability to determine the glucose concentration in diluted human serum samples at a high recovery percentage, demonstrated its viability as a nonenzymatic glucose sensor.

Construction of oxygen-vacancy-rich Z-scheme polypyrrole/Bi2SiO5 heterojunction for efficient degradation of antibiotics under simulated sunlight

A Z-scheme polypyrrole/Bi2SiO5 heterojunction rich in oxygen vacancies was prepared by combining the organic polymer polypyrrole with Bi2SiO5 via a hydrothermal method and an oxidative polymerization reaction. The photocatalyst exhibited good stability in water and effectively degraded tetracycline, oxytetracycline, ciprofloxacin, norfloxacin, and doxycycline under simulated sunlight, indicating its excellent potential for wastewater treatment. In particular, the efficiency of tetracycline removal by the optimized polypyrrole/Bi2SiO5 composite after 120 min of irradiation was 93.1%, approximately 2.1 times that of Bi2SiO5. The exceptional photocatalytic performance of polypyrrole/Bi2SiO5 stemmed from the construction of a Z-scheme heterostructure and generation of oxygen vacancies induced by the introduction of polypyrrole. Furthermore, liquid chromatography–mass spectrometry (LC-MS) was used to investigate the intermediate products of tetracycline degradation, and possible degradation pathways were deduced. Finally, a possible photocatalytic mechanism was proposed based on the results of electron paramagnetic resonance and free radical capture experiments.

Synthesis and characterization of PANI-ZrWPO4 nanocomposite: adsorption-reduction efficiency and regeneration potential for Cr(VI) removal.

A novel polyaniline zirconium tungstophosphate (PANI-ZrWPO4) nanocomposite was successfully synthesized through an in situ oxidative polymerization reaction followed by a microwave irradiation process. The synthesized nanocomposite was characterized by using FESEM, EDX, TEM, XRD, FTIR, Raman, TGA-DTA, XPS, and N2 adsorption-desorption analysis and chemical analysis to know about the formation of material. The results of the FTIR and Raman spectra confirmed that the conducting PANI polymer interacted with ZrWPO4 to form the PANI-ZrWPO4 nanocomposite. The XRD data showed that the composite had a crystalline nature. The TEM and FESEM images revealed that polyaniline had formed on the exterior of the PANI-ZrWPO4 nanocomposite. Further investigation was done on the efficiency of the PANI-ZrWPO4 nanocomposite as an adsorbent for Cr(VI) removal through batch adsorption experiments. The maximum Langmuir adsorption capacity of PANI-ZrWPO4 was found to be 71.4mgg-1. The removal of Cr(VI) was optimized with the six variables namely adsorbent dose, initial concentration, Time, pH, Temperature, and stirring rate using the Box-Behnken design (BBD) model. The XPS spectra confirmed simultaneously adsorption reduction occurs Cr(VI) to Cr(III) through in situ chemical reduction. Moreover, the regeneration efficiency of PANI-ZrWPO4 was studied, and it was found to be able to remove around 80% of Cr(VI) even after five cycles, demonstrating its potential as an effective and reusable adsorbent.

Versatile Hydrogel Dressings That Dynamically Regulate the Healing of Infected Deep Burn Wounds.

Severe burns threaten patient lives due to pain, inflammation, bacterial infection, and scarring. Most burn dressings that are commonly used perform a single function and are not well suited for the management of deep burns. Therefore, a multifunctional antimicrobial peptide- and stem cell-loaded macroporous hydrogel that can fight bacterial infection and regulate wound healing progression by temporally regulating cytokine production by internal stem cells is developed. The macroporous skeletal hydrogel is manufactured via the cryogenic gelation of hyaluronic acid (cryogel). Based on the oxidative polymerization reaction of dopamine, the antimicrobial peptide DP7 is immobilized on the surface of the cryogel (DA7CG). Placental mesenchymal stem cells (PMSCs) are then packaged inside the macroporous hydrogel (DA7CG@C). According to the results of in vitro and in vivo experiments, during the inflammatory phase, DP7 inhibits infection and modulates inflammation; during the proliferative phase, DA7CG@C accelerates the regeneration of skin, blood vessels, and hair follicles via internal stem cells; and during the remodeling phase, DA7CG@C contributes to extracellular matrix remodeling due to the ability of DP7 to regulate the paracrine secretion of PMSCs, synergistically promoting scar-free healing. DA7CG@C can participate in all phases of wound healing; therefore, it is a promising dressing for burn treatment.

Substituent effects of amines on genipin dye formation – Insights into dye origin

Genipin, a naturally occurring iridoid, represents an interesting class of reactive dyes. This colorless molecule produces brilliant blue dyes in the presence of primary aliphatic amines. The mechanism behind this unique reaction has been suggested to proceed via an oxidative polymerization reaction. By utilizing aromatic amines, we demonstrate that the dye absorption properties can be redshifted to form green dyes as opposed to the blue that is most associated with aliphatic amines. These results led us to explore the mechanism of dye formation using X-Ray crystallography, DFT calculations, electrochemical experiments, mass spectrometry, and EPR spectroscopy on slightly structurally perturbed genipin scaffolds. Herein we report the first findings of a crystallographically characterized pseudoazulenic genipin dye intermediate and the impacts of redox chemistry on the resulting dyes, which shows electrochromic reversibility.

Design and synthesis of thiophene containing bis-chalcone-based mesoporous polymers for volatile iodine capture

Two novel thiophene-containing bis-chalcone-based polymers poly [(1E,4E)-1,5-Di-2-thienylpenta-1,4-dien-3-one] (PTCA) and poly[(1E,4E)-2,4-dimethyl-1,5-di(thiophen-2-yl)penta-1,4-dien-3-one] (PTCM) were designed and synthesized by FeCl3 mediated oxidative coupling polymerization reaction. The formation of polymers was confirmed by FT-IR and UV-DRS analysis, and the structural and morphological characterizations were done by PXRD, SEM, TEM, TGA, CHNS, and BET analysis techniques. Owing to their mesoporous nature, and excellent thermal and chemical stability, they found significant applications in the field of environmental remediation. Regardless of their low surface area, they emerged as strong candidates for the iodine capture process due to the presence of electron-rich heteroatoms. The maximum iodine capture capacity obtained for PTCA and PTCM were 242 and 221 wt.% respectively. The kinetic study revealed that the adsorption of iodine onto the polymers fit well in the pseudo-second-order kinetic model with a correlation coefficient R2 > 0.99, pointing to the chemisorptive nature of adsorption. The polymers can be competently recycled and reused even after five cycles without a significant loss of iodine uptake. After the first cycle, the iodine release efficiency was as high as 89% and 93% for PTCA and PTCM respectively. The iodine uptake capacity of the reused polymers PTCA and PTCM was found to be 89.2% and 86.5% respectively after five successive cycles. And these materials offer the benefits of facile, low-cost, large-scale, and template-free synthesis of mesoporous polymers. This study also provides an opportunity for the design same kind of polymers with different heteroatoms and functional groups.

Efficiency of humin immobilized in manganese–alginate beads for improving irreversible sorption and oxidative removal of 1-naphthol

Despite the high reactivity of birnessite for the oxidative removal of phenolic compounds, its radicals are persistent, and they adversely affect water systems. Alginate beads are widely used for secondary contaminant adsorption; however, they exhibit limited adsorption performance. To improve the efficiencies of birnessite and alginate for phenolic compound removal, humin was successfully immobilized in the sodium alginate beads to form birnessite–humin–alginate (Mn-Hu-AG) beads with various initial humin mass ratios (e.g. 1:0.25:1, 1:0.5:1, and 1:1:1). After the reaction between the Mn-Hu-AG beads and 1-naphthol, the products were analyzed using ultraviolet–visible spectrophotometry, high-performance liquid chromatography (HPLC), and infrared spectroscopy to evaluate the 1-naphthol-removal efficiency. The Mn-Hu-AG beads exhibited pseudo-second-order reaction kinetics, and the Mn-AG beads pseudo-first-order reaction kinetics. This indicates that both birnessite and humin are involved in the oxidative polymerization reaction between 1-naphthol and manganese oxide. The half-life of the Mn-Hu-AG beads (second-order reaction rate) was 3.7 times lower than that of the Mn-AG beads (first-order reaction rate). The Mn-Hu-AG beads exhibited a higher 1-naphthol removal rate than the Mn-AG beads, including further removal of the reaction products and Mn2+ elution from the reaction. In addition, the post-reaction HPLC results of the supernatant and the Mn-AG-Hu-bead extracts confirmed that humin immobilized the 1-naphthol reaction products via irreversible adsorption onto the Mn-AG-Hu-bead surface via birnessite-mediated cross-coupling. Because humin is eco-friendly and insoluble, its successful application in Mn-Hu-AG beads can be useful in developing effective materials for environmental remediation.

Mussel-inspired polydopamine functionalized with ionic liquid as a novel, eco-efficient adsorbent for the selective removal of anionic pollutants from aqueous solutions

In this work, novel mussel-inspired polydopamine nanoparticles functionalized with ionic liquid (PDA-IL) were synthesized via one step oxidative polymerization and Schiff-base addition reaction using dopamine and ionic liquid (3-aminopropylammonium acetate). The synthesized polydopamine-ionic liquid (PDA-IL) was utilized as an efficient adsorbent in the removal of anionic dyes from aqueous solutions, using Alizarin Red S (ARS) as a model pollutant. Multiple analytical tools, including scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy and Zeta potential were applied in the characterizations of PDA-IL. A parametric study was conducted to examine the effects of pH, contact time, initial concentration, adsorbent dose, and temperature on PDA-IL adsorption performance. Characterization results confirmed the formation of nano-sized PDA-IL particles with polycrystalline structure. Additionally, the porous structure, surface charge, surface moieties and thermal stability were progressively tuned along with the introduction of the custom-synthesized IL within the matrix of PDA. Results showed a significant maximum ARS adsorption capacity of PDA-IL, up to 234.2 mg g−1 at 25 °C. Adsorption kinetics data revealed a pseudo-second-order kinetics, governed by chemisorption. Equilibrium data for ARS removal were in agreement with Freundlich isotherm, indicating multilayer adsorption on the heterogeneous PDA-IL surface. Furthermore, regeneration studies demonstrated an efficient re-use of PDA-IL adsorbent in at least 4 adsorption/desorption cycles. A selectivity study was also conducted, which showed that PDA-IL selectivity towards anionic dyes can be tuned via pH control. Finally, an adsorption mechanism was proposed, based on FTIR and electron energy loss spectroscopy (EELS) mapping results, among others, for an understanding of the underlying adsorption phenomena on PDA-IL. Overall, the developed PDA-IL adsorbent had a great removal capacity of anionic ARS dye, fast adsorption kinetics, excellent selectivity towards anionic dyes and high regeneration efficiency.

Polyaniline-supported nano metal-catalyzed coupling reactions: Opportunities and challenges

Polyanilines (PANIs) can be easily prepared from the available and cheap anilines via the oxidative polymerization reactions. Owing to the coordination of nitrogen in the material with metals, PANIs are widely used as the support of nano metal catalysts. In comparison with inorganic supports, the nano metals on PANIs were firmly anchored via the coordination bond so that they are not easily to lose during the reaction process. Moreover, since PANIs are versatile materials and their chemical features can be adjusted by introducing functional groups onto the monomers, the catalytic activities of the prepared catalysts are tunable. During the past decade, PANIs-supported nano metal catalysts have been widely applied in a variety of coupling reactions. This review aims to summarize the recent advances and give a perspective.

Cu-Doped Polypyrrole with Multi-Catalytic Activities for Sono-Enhanced Nanocatalytic Tumor Therapy.

Nanocatalytic medicine is a burgeoning disease treatment model with high specificity and biosafety in which the nanocatalyst is the core of driving catalytic reaction to generate therapeutic outcomes. However, the robust defense systems in the pathological region would counteract nanocatalyst-initiated therapeutics. Here, a Cu-doped polypyrrole is innovatively developed by a facile oxidative polymerization reaction, which exhibits intriguing multi-catalytic activities, including catalyzing H2 O2 to generate O2 and · OH, and consuming reduced glutathione by a Cu(II)-Cu(I) transition approach. By decorating with sonosensitizers and DSPE-PEG, the obtained CuPPy-TP plus US irradiation can induce severe oxidative damage to tumor cells by amplifying oxidative stress and simultaneously relieving antioxidant capacity in tumors based on the highly effective sonochemical and redox reactions. The notable tumor-specific biodegradability, remarkable cell apoptosis in vitro, and tumor suppression in vivo are demonstrated in this work, which not only present a promising biocompatible antitumor nanocatalyst but also broaden the perspective in oxidative stress-based antitumor therapy.

Assessment of self-doped poly (5-nitro-2-orthanilic acid) as a scaling inhibitor to control the precipitation of CaCO3 and CaSO4 in solution

Self-doped- and nitro-polyanilines have become a widely used strategy to optimize the electronic and vibratory spectra of polymeric building blocks in various applications. We report the synthesis of poly (5-nitro-2-orthanilic acid) by an aniline-initiated oxidative polymerization reaction. The polymer is characterized by spectroscopic techniques, elemental shapes, cyclic voltammetry, electrical conductivity, and microscopic and thermal measurements. The hydrophilic and hydrophobic nature of the supports provided the formation of amphiphilicity as judged by SEM. Thermogravimetric measurements reveal thermal stability up to 500 °C and glass temperature (Tg) observed at 240 °C. Electrical conductivity decreases as the temperature rises at the different frequencies used, reflecting the semiconducting nature in the extrinsic range, which is characterized by high carriers and low mobility. The presence of these electron residues causes a decrease in efficiency and increases the thermal conductivity. Dielectric measurements have shown that permittivity decreases gradually at lower levels, mainly due to the transport of charging carriers, resulting in higher performance. The testing of the copolymer as a new scale blocker has resulted in moderate to fairly high performance. This effect is attributed to the change in polymer geometry using intramolecular H-bonding group -SO3H and a chain polymer in an aqueous medium.

Preparation and electroactuation of water-based polyurethane-based polyaniline conductive composites

Abstract Ionic polymer-based conductive composite is a new type of ionic electroactive polymer smart material, which is composed of two electrodes, the ion-exchange polymer matrix film and the polymer surface and is a three-layer sandwich structure. The conductive composite material has the advantages of flexibility, portability, and biocompatibility, which has attracted a large number of researchers to study it in the fields of biomimetic flexible actuators and biomedical materials, but the conventional matrix film has the disadvantage of high preparation cost. In this study, using sulfonated waterborne polyurethane membrane as matrix membrane and aniline as monomer, polyaniline (PANI) was synthesized by in situ oxidation polymerization reaction, and the conductive composites with PANI as electrode were prepared. After applying alternating current electric field, a new brake with PANI as electrode is obtained. A low-frequency signal generator was used to study the electromechanical properties of the prepared materials. The results show that the waterborne polyurethane/PANI composite film produces a continuous and stable driving performance at 0.2 Hz and 20 V, and the maximum output displacement of the terminal is 40 mm. When the driving voltage and frequency are changed, the displacement output also changes, showing a good controllable performance. Its structure and morphology were characterized.

Anomalous activation behavior of the conductivity mechanisms in polyaniline-doped graphitic carbon nitride

Incorporation of graphitic carbon nitride (g-CN) in a conductive polymer matrix has been used for different applications. However, the conductivity behavior of the conjugated polymer in the presence of g-CN still needs thorough exploring. This work investigates the electric conductivity of polyaniline/g-CN nanocomposites synthesized via an in situ oxidative polymerization reaction. The chemical structure of the prepared materials was studied using Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrical and dielectric parameters were measured and calculated through broadband dielectric spectroscopy. The temperature dependence of the permittivity shows different trends depending on the polarization and conductivity mechanisms. The DC conductivity of all samples varies only by one order of magnitude. Its value at 373 K increases from 0.21 mS/cm for 1% g-CN to 2.2 mS/cm for 5% g-CN. However, the DC conductivity reduces again to 1.6 mS/cm for the sample containing 7% g-CN. The charge carrier mobility has a dominant effect on the conductivity, and its activation behavior shows unusual characteristics.

Oxidative Polymerization in Living Cells.

Intracellular polymerization is an emerging technique that can potentially modulate cell behavior, but remains challenging because of the complexity of the cellular environment. Herein, taking advantage of the chemical properties of organotellurides and the intracellular redox environment, we develop a novel oxidative polymerization reaction that can be conducted in cells without external stimuli. We demonstrate that this polymerization reaction is triggered by the intracellular reactive oxygen species (ROS), thus selectively proceeding in cancer cells and inducing apoptosis via a unique self-amplification mechanism. The polymerization products are shown to disrupt intracellular antioxidant systems through interacting with selenoproteins, leading to greater oxidative stress that would further the oxidative polymerization and eventually activate ROS-related apoptosis pathways. The selective anticancer efficacy and biosafety of our strategy are proven both in vitro and in vivo. Ultimately, this study enables a new possibility for chemists to manipulate cellular proliferation and apoptosis through artificial chemical reactions.