Organic Macromolecules Research Articles

Electrochemical Analysis of Heavy Metal Ions Using Conducting Polymer Interfaces

Conducting polymers (CPs) are highly conjugated organic macromolecules, where the electrical charge is transported in intra- and inter-chain pathways. Polyacetylene, polythiophene and its derivatives, polypyrrole and its derivatives, and polyaniline are among the best-known examples. These compounds have been used as electrode modifiers to gain sensitivity and selectivity in a large variety of analytical applications. This review, after a brief introduction to the electrochemistry of CPs, summarizes the application of CPs’ electrode interfaces towards heavy metals’ detection using potentiometry, pulse anodic stripping voltammetry, and alternative non-classical electrochemical methods.

Confined Construction of Ultrasmall Molybdenum Disulfide-Loaded Porous Silica Particles for Efficient Tumor Therapy.

Recently, molybdenum sulfide (MoS2) has shown great application potential in tumor treatment because of its good photothermal properties. Unfortunately, most of the current molybdenum disulfide-based nanotherapeutic agents suffer from complex preparation processes, low photothermal conversion efficiencies, and poor structural/compositional regulation. To address these issues, in this paper, a facile "confined solvothermal" method is proposed to construct an MoS2-loaded porous silica nanosystem (designated as MoS2@P-hSiO2). The maximum photothermal efficiency of 79.5% of molybdenum-based materials reported in the literature at present was obtained due to the ultrasmall MoS2 nanoclusters and the rich porous channels. Furthermore, both in vitro and in vivo experiments showed that the cascade hybrid system (MoS2/GOD@P-hSiO2) after efficient loading of glucose oxidase (GOD) displayed a significant tumor-suppressive effect and good biosafety through the combined effects of photothermal and enzyme-mediated cascade catalytic therapy. Consequently, this hybrid porous network system combining the in situ solvothermal strategy of inorganic functional components and the efficient encapsulation of organic enzyme macromolecules can provide a new pathway to construct synergistic agents for the efficient and safe treatment of tumors.

Photoelectrochemical sensors based on heterogeneous nanostructures for in vitro diagnostics

In vitro diagnostics with biochemical sensors are one of the most important technologies for medical diagnosis and the examination of human health. With the improvement of people's living standards, the demand for in vitro diagnostics is increasing, and the requirements for the performance of biochemical sensors are also getting higher. Compared to other biochemical sensors, photoelectrochemical sensors based on heterogeneous nanostructures have excellent light absorption ability and electron transfer performance, and are powerful alternatives for the detection of chemical substances and biochemical molecules for in vitro diagnostics. And this is the main reason why they are a hot topic among relevant analytical methods. However, comprehensive and detailed analyses based on these sensors are rarely reported, especially for in vitro diagnostics, so a complete review of this field is necessary. This review outlines the advantages and disadvantages of various current sensors and further demonstrates the superiority of photoelectrochemical sensors based on heterogeneous nanostructures by comparison. In addition, a detailed classification, introduction of principles and analysis of synthesis methods of heterogeneous nanostructured photoelectrochemical sensors are presented. Based on the above analysis, a detailed description of the use of this type of sensor for in vitro diagnosis of inorganic and organic (micromolecules and macromolecules) molecules in recent years is presented. Predicting and combating relevant diseases are realized by in vitro detection of molecules. Finally, it paves the way for subsequent researchers in the process of realizing practical applications of photoelectrochemical sensing based on heterogeneous nanostructures.

(Invited, Digital Presentation) Synthesis of Multi-Metallic Clusters Using a Dendrimer Reactor

Dendrimers are highly branched organic macromolecules with successive layers or “generations” of branch units surrounding a central core. Organic inorganic hybrid versions have also been produced, by trapping metal ions or metal clusters within the voids of the dendrimers. Their unusual, tree-like topology endows these nanometer-sized macromolecules with a gradient in branch density from the interior to the exterior, which can be exploited to direct the transfer of charge and energy from the dendrimer periphery to its core.We show that tinchloride, SnCl2 and FeCl3 complexes to the imines groups of a spherical polyphenylazomethine dendrimer in a stepwise fashion according to an electron gradient, with complexation in a more peripheral generation proceeding only after complexation in generations closer to the core has been completed. By attaching an electron-withdrawing group to the dendrimer core, we are able to change the complexation pattern, so that the core imines are complexed last. By further extending this strategy, it should be possible to control the number and location of metal ions incorporated into dendrimer structures, which might and uses as tailored catalysts, building blocks, or fine-controlled clusters for advanced materials. The metal-assembly in a discrete molecule can be converted to a size-regulated metal particle with a size smaller than 1 nm as a molecular reactor. Due to the well-defined number of metal clusters in the subnanometer size region, its property is much different from that of bulk or general metal nanoparticles. The chemistry of metal clusters on the sub-nanometer scale is not yet well understood because metal clusters, especially multi-metallic clusters, are difficult to synthesize with control over size and composition. The template synthesis of multi-metallic sub-nanoclusters is achieved using a phenylazomethine dendrimer as a macromolecular template.

Effects of humic acid and kaolinite on copper transport in water‐saturated porous media

AbstractMobile organic macromolecules and inorganic particles may act as carriers of strongly sorbing contaminants in subsurface materials, posing a potential facilitated transport risk. This study examined the influence of humic acid (HA) and kaolinite colloid on copper ion transport in saturated porous media. Column experiments were conducted to investigate the migration behavior and interactions of HA, kaolinite and copper under different experimental conditions in saturated porous media. The results showed that the individual presence of HA promoted the transport of Cu. However, the mixture of kaolinite and HA has less effect on Cu migration than HA alone. The presence of Cu reduced the mobility of kaolinite through the saturated porous media sand column by increasing the deposition rate of kaolinite. The transport of kaolinite increased significantly in the presence of HA, while kaolinite slightly decreased HA transport in the sand column. Compared with kaolinite, HA has a stronger ability to desorb copper from copper‐bearing sand. Considering the presence of kaolinite and HA, this study provides a reference for the fate, migration and risk assessment of heavy metal pollutants.

A Precise Closed-Loop Controlled ZnO Nanowire Resonator Operating at Room Temperature.

To realize the real-time measurement of masses of nanoparticles, virus molecules, organic macromolecules, and gas molecules, and to analyze their physical and chemical properties, a ZnO nanowire (NW) resonator operating at room temperature with an ultrahigh resonant frequency, real-time detection, and high precision was designed and developed in this study. The machining method is simple and easy to integrate into an integrated circuit. A closed-loop detection system based on a phase-locked loop (PLL) and frequency modulation technology (FM) was used to perform closed-loop testing of electromagnetically excited ZnO NW. The first-order resonance frequency of the resonator was 10.358 MHz, the quality factor Q value was about 600, the frequency fluctuation value fRMS was about 300 Hz, and the FM range could reach 200 kHz. The equivalent circuit model of the resonator was established, the parasitic parameters during the test were obtained, and the frequency accuracy and phase noise of the resonator were analyzed and tested. The experimental results show that the closed-loop system can automatically control the resonator in a wide range of frequency bands, with good tracking performance of the resonant frequency, small frequency fluctuation, and low phase noise level.

Laboratory Research on Design of Three-Phase AC Arc Plasma Pyrolysis Device for Recycling of Waste Printed Circuit Boards

Accumulation of electronic waste (e-waste) will place a heavy burden on the environment without proper treatment; however, most ingredients contained in it are useful, and it could bring great economic benefits when recycled. A three-phase alternating current (AC) arc plasma pyrolysis device was designed for resourcing treatment of waste printed circuit boards (WPCBs). This paper focuses on the analysis of plasma pyrolysis gas products, and the results showed that the plasma could operate stably, and overcame the problems of the poor continuity and low energy of single-arc discharge. Air-plasma would generate NOx contaminants, burn the organics, and oxidize the metals; therefore, air had not been selected as a working gas. Ar-plasma can break the long chains of organic macromolecules to make a combustible gas. Moreover, the strong adhesion between the metals and fiberglass boards would be destroyed, which facilitates subsequent separation. Ar/H2-plasma promoted the decrease of carbon dioxide and the increase of combustible small molecular hydrocarbons in the pyrolysis product compared with Ar-plasma, and the increase of the H2 flow rate or plasma power intensified that promotion effect. The percentage of other components, except the hydrogen of CO2, CO, CH4, C2H4, and C3H6, accounted for 55.7%, 34.2%, 5.6%, 4.5%, and 0% in Ar-plasma, and changed to 35.0%, 29.0%, 11.2%, 24.3%, and 0.5% in Ar/H2-plasma. Ar/H2-plasma could provide a highly chemically active species and break chemical bonds in organic macromolecules to produce small molecules of combustible gas. This laboratory work presents a novel three-phase AC arc plasma device and a new way for recycling WPCBs with high value.

Novel Acrylamide/2-Acrylamide-2-3 Methylpropanesulfonic Acid/Styrene/Maleic Anhydride Polymer-Based CaCO3 Nanoparticles to Improve the Filtration of Water-Based Drilling Fluids at High Temperature.

Filtration loss control under high-temperature conditions is a worldwide issue among water-based drilling fluids (WBDFs). A core–shell high-temperature filter reducer (PAASM-CaCO3) that combines organic macromolecules with inorganic nanomaterials was developed by combining acrylamide (AM), 2-acrylamide-2-methylpropane sulfonic acid (AMPS), styrene (St), and maleic anhydride (MA) as monomers and nano-calcium carbonate (NCC). The molecular structure of PAASM-CaCO3 was characterized. The average molecular weight of the organic part was 6.98 × 105 and the thermal decomposition temperature was about 300 °C. PAASM-CaCO3 had a better high-temperature resistance. The rheological properties and filtration performance of drilling fluids treated with PAASM-CaCO3 were stable before and after aging at 200 °C/16 h, and the effect of filtration control was better than that of commonly used filter reducers. PAASM-CaCO3 improved colloidal stability and mud cake quality at high temperatures.

Cellular sentience as the primary source of biological order and evolution

All life is cellular, starting some 4 billion years ago with the emergence of the first cells. In order to survive their early evolution in the face of an extremely challenging environment, the very first cells invented cellular sentience and cognition, allowing them to make relevant decisions to survive through creative adaptations in a continuously running evolutionary narrative. We propose that the success of cellular life has crucially depended on a biological version of Maxwell's demons which permits the extraction of relevant sensory information and energy from the cellular environment, allowing cells to sustain anti-entropic actions. These sensor-effector actions allowed for the creative construction of biological order in the form of diverse organic macromolecules, including crucial polymers such as DNA, RNA, and cytoskeleton. Ordered biopolymers store analogue (structures as templates) and digital (nucleotide sequences of DNA and RNA) information that functioned as a form memory to support the development of organisms and their evolution. Crucially, all cells are formed by the division of previous cells, and their plasma membranes are physically and informationally continuous across evolution since the beginning of cellular life. It is argued that life is supported through life-specific principles which support cellular sentience, distinguishing life from non-life. Biological order, together with cellular cognition and sentience, allow the creative evolution of all living organisms as the authentic authors of evolutionary novelty.

Enhanced Growth Inhibition and Apoptosis Induction in Human Colon Carcinoma HT-29 Cells of Soluble Longan Polysaccharides with a Covalent Chemical Selenylation.

The selenylated polysaccharides chemically belong to the organic Se-conjugated macromolecules and have recently been attracting more and more attention due to their potential to promote body health or prevent cancers. Longan (Dimocarpus longan L.), as a subtropical fruit, contains soluble and non-digestible polysaccharides that are regarded with health care functions in the body. In this study, the longan polysaccharides (LP) were obtained via enzyme-assisted water extraction, and then chemically selenylated using a reaction system composed of HNO3–Na2SeO3 to yield two selenylated products, namely, SeLP1 and SeLP2, with Se contents of 1.46 and 4.79 g/kg, respectively. The anti-cancer effects of the three polysaccharide samples (LP, SeLP1, and SeLP2) were thus investigated using the human colon cancer HT-29 cells as the cell model. The results showed that SeLP1 and SeLP2 were more able than LP to inhibit cell growth, alter cell morphology, cause mitochondrial membrane potential loss, increase intracellular reactive oxygen and [Ca2+]i levels, and induce apoptosis via regulating the eight apoptosis-related genes and proteins including Bax, caspases-3/-8/-9, CHOP, cytochrome c, DR5, and Bcl-2. It was thereby proven that the selenylated polysaccharides could induce cell apoptosis via activating the death receptor, mitochondrial-dependent, and ER stress pathways. Collectively, both SeLP1 and SeLP2 showed higher activities than LP in HT-29 cells, while SeLP2 was consistently more active than SeLP1 in exerting these assessed anti-cancer effects on the cells. In conclusion, this chemical selenylation covalently introduced Se into the polysaccharide molecules and caused an enhancement in their anti-cancer functions in the cells, while higher selenylation extent was beneficial to the activity enhancement of the selenylated products.

Some peculiarities of triplet excitations dynamics in organic macromolecules and crystals

Spectral properties of polymer macromolecules in the optical energy range and relation of these properties to the chemical structure and energy levels system of polymers were examined. The nature of optical centers of the macromolecules with π-electron systems localized on separate groups (so-called chromophores) was analyzed. It was stressed that such vitally important biopolymers as DNA and RNA belong to this type of polymers. It was shown that in synthetic and biological macromolecules with pendant aromatic groups, the triplet excitons meet and annihilate with the very high probability due to large lifetime and one-dimensional motion. The presented results prove that efficiency of triplet-triplet annihilation processes (at the used excitation power) is higher than efficiencies of other electronic processes. Consideration of this fact in the kinetic equation for triplet excitons in macromolecule leads to inverse square root dependence of phosphorescence intensity on the macromolecule length. At the same time, for three-dimensional molecular crystals of stilbene and para-terphenyl, the intensity of the delayed fluorescence is less dependent on the size of the granules compared to the dependence of the delayed fluorescence intensity on the length for one-dimensional macromolecules.

Organic Macromolecule regulated the structure of vanadium oxide with high capacity and stability for aqueous Zinc-ion batteries

The aqueous zinc-ion rechargeable batteries (AZIBs) have become a promising alternative for large-scale energy storage applications and triggered a great deal of scientific research due to low cost, high security, and eco-efficiency. Here, we report the successful synthesis of phytic acid coated/inserted V2O5 nano-composites (PHVO) by one-step hydrothermal method. On one hand, the surface of V2O5 nanosheets is uniformly coated by phytic acid to form an ultrathin layer, serving as a stabilizer to greatly enhance the structural stability by restraining the exfoliation of active materials during the cycling process. On the other hand, the phytic acid plays as the intercalary spacer to expand the V2O5 interlayer distance to 13.5 Å, which is beneficial to the diffusion kinetics of Zn2+ by offering expedited channels. With the abovementioned advantages, the overall electrochemical performance of PHVO has been significantly improved. It showed an excellent specific capacity of 406 mAh g−1 at 0.1 A g−1, and the capacity retention rate was 97.3% after 6000 cycles at 5 A g−1. This work paves the way to the design and fabrication of stable cathodes for AZIBs with excellent electrochemical performance.

In vivo electrochemically-assisted polymerization of conjugated functionalized terthiophenes inside the vascular system of a plant

We investigate the possibility of producing biofuel cell electrode materials in vivo by injecting the reagents directly into plant tissues. We first introduce model electroactive substances Fe(CN)64− and Ru(NH3)63+ into a Nicotiana tabacum leaf. In situ electrochemical measurements make it possible to trace the distribution of these substances. As well as mapping the vascular content, electrochemistry can be used to trigger reactions directly inside the plant. The injection of thiophene (T) and ethylenedioxythiophene (E)-based trimers (ETE) anchoring an Os(2,2′-bipyridine)2(1-(3-aminopropyl)-imidazole)Cl Os-complex followed by the application of anodic polarization triggers a polymerization reaction in the region of the plant vascular system containing the monomer, showing that it is possible to generate electroactive organic macromolecules locally in vivo.

Hydrogen Sulfide Production with a Microbial Consortium Isolated from Marine Sediments Offshore

Hydrogen, electric energy production, and metal toxic bioremediation are some of the biotechnological applications of sulfate-reducing organisms, which potentially depend on the sulfide produced. In this study, offshore of Yucatan, the capacity to produce hydrogen sulfide using microbial consortia from marine sediment (SC469, PD102, SD636) in batch reactors was evaluated. Kinetic tests were characterized by lactate oxidation to acetate, propionate, CO2 and methane. The inoculum SC469, located in open-ocean, differed strongly in microbial diversity and showed better performance in substrate utilization with the highest hydrogen sulfide production (246 mmolg−1 VSS) at a specific hydrogen sulfide rate of 113 mmol g−1 VSS d−1 with a 0.79 molar ratio of sulfate/lactate. Sulfate-reducing microbial consortia enriched in the laboratory from marine sediments collected offshore in Yucatan and with a moderate eutrophication index, differed strongly in microbial diversity with loss of microorganisms with greater capacity for degradation of organic macromolecules. The sulfate-reducing microorganisms were characterized using Illumina MiSeq technology and were mainly Desulfomicrobium, Clostridium and Desulfobacter.

Expeditious and effectual capacitive deionization performance by chitosan-based carbon with hierarchical porosity

Capacitive deionization (CDI) technology is a high-efficiency, energy-saving, green and environmentally friendly new water treatment technology, which will have potential in the field of low-salinity seawater desalination. Current carbon-based electrode materials have limited desalination capacity and rate due to insufficient ion-accessible specific surface area and slow ion transmission rate. Here, we demonstrate layered porous carbon (CHPC) derived from Chitosan, colloidal SiO2 and polytetrafluoroethylene (PTFE) mixed carbonization for efficient CDI desalination. CHPC has abundant macropores that are connected with mesopores. This layered porous structure enables CHPC to have a faster ion migration rate. The salt removal capacity of CHPC reaches 26.5 ± 1.5 mg/g, and the average adsorption rate is 8.8 ± 0.5 mg/g/min, which are about 1.6 and 10 times than that of commercial activated carbon, respectively. In addition, CHPC has extremely strong anti-interference performance against organic macromolecules, which could maintain more than 95% adsorption capacity after 30 cycles. Our work helps to promote the practical application of hierarchical porous structures based on typical biomass in large-capacity and fast-rate CDI desalination technology.

Tunable metallic-like transport in polypyrrole

Abstract Conjugated polymers (CPs), organic macromolecules with a linear backbone of alternating C–C and C=C bonds, possess unique semiconductive properties, providing new opportunities for organic electronics, photonics, information, and energy devices. Seeking the metallic or metallic-like, even superconducting properties beyond semiconductivity in CPs is always one of the ultimate goals in polymer science and condensed matter. Only two metallic and semi-metallic transport cases—aniline-derived polyaniline and thiophene-derived poly(3,4-ethylenedioxythiophene)—have been reported since the development of CPs for four decades. Controllable synthesis is a key challenge in discovering more cases. Here we report the metallic-like transport behavior of another CP, polypyrrole (PPy). We observe that the transport behavior of PPy changes from semiconductor to insulator-metal transition, and gradually realizes metallic-like performance when the crystalline degree increases. Using a generalized Einstein relation model, we rationalized the mechanism behind the observation. The metallic-like transport in PPy demonstrates electron strong correlation and phonon–electron interaction in soft condensation matter, and may find practical applications of CPs in electrics and spintronics.

Removal of low-concentration nickel in electroplating wastewater via incomplete decomplexation by ozonation and subsequent resin adsorption

Effective removal of low-concentration chelated nickel in electroplating wastewater to meet the strictest discharge standard for nickel less than 0.1 mg/L has long been a challenging task. Herein, a method combining ozonation and resin adsorption was successfully used to remove the initial total Ni concentration of below 10 mg/L at ozone dosage of 8–38 mg/L. It is notable that the nickel complexation was destroyed by ozone while the co-existing organic matters were not completely mineralized. After ozonation, even the common cation-exchange resin can successfully remove the nickel. The fixed-bed adsorption experiment showed that the working capacity of cation-exchange resin for the ozonated wastewater was 1150 bed volume (BV) at the nickel breakthrough point of 0.1 mg/L, much higher than 5 BV without ozonation treatment. Three-dimensional fluorescence and HPLC-QTOF-MS were employed to characterize the change of Ni-complexes during the treatment process. The decomplexation mechanism of Ni-complexes by ozonation and removal mechanism by cation-exchange resins were proposed. After ozonation, the organic macromolecules were degraded into small molecular acids, which could chelate nickel with one carboxyl group and form positively charged complexes. These nickel complexes were readily adsorbed to the cation-exchange resin via cation exchange or complete complexation, enhancing the removal efficiency. Accordingly, ozone oxidation and subsequent resin adsorption are effective for the removal of low-concentration chelated nickel from electroplating wastewater.

Strategic Design for Sumanene‐Derived Organic Cathodes with Tailored Redox Activity

AbstractDespite the use of organic macromolecules in durable, high‐performance lithium‐ion battery cathodes, relevant studies are still lacking. Herein, sumanene, a representative macromolecule, and its derivatives are introduced through either individual or combined incorporation of two distinct functional groups, namely carbonyls and cyanides, to understand the effects of the functionalization strategy on their electrochemical redox properties. This computational investigation reveals that the combined incorporation of the two distinct redox‐active sites would synergistically improve the open‐circuit redox potential, ultimately leading to an exceptionally high theoretical performance of a sumanene‐derivative fully functionalized with carbonyl and cyanide. Furthermore, this study enables to draw meaningful conclusions on the three discharging stages, namely the fully charged, ongoing, and fully discharged stages. Clearly, the open‐circuit redox potential of a compound corresponding to the fully charged stage depends on its electron affinity that is dominantly contributed by the charging energy. During the discharging process, the redox potentials of the compounds gradually decrease with the increase in the number of bound Li atoms because of the Li‐induced weakening of its reductive ability owing to the continuous increase in its charging energy, leading to the cooperative contribution of charging and reorganization energies to the redox potential. At the end of the discharging process, the compound loses the cathodic activity with a negative redox potential, primarily owing to a sudden increase in solvation energy.

Layer-by-Layer Deposition: A Promising Environmentally Benign Flame-Retardant Treatment for Cotton, Polyester, Polyamide and Blended Textiles

A detailed review of recent developments of layer-by-layer (LbL) deposition as a promising approach to reduce flammability of the most widely used fibers (cotton, polyester, polyamide and their blends) is presented. LbL deposition is an emerging green technology, showing numerous advantages over current commercially available finishing processes due to the use of water as a solvent for a variety of active substances. For flame-retardant (FR) purposes, different ingredients are able to build oppositely charged layers at very low concentrations in water (e.g., small organic molecules and macromolecules from renewable sources, inorganic compounds, metallic or oxide colloids, etc.). Since the layers on a textile substrate are bonded with pH and ion-sensitive electrostatic forces, the greatest technological drawback of LbL deposition for FR finishing is its non-resistance to washing cycles. Several possibilities of laundering durability improvements by different pre-treatments, as well as post-treatments to form covalent bonds between the layers, are presented in this review.

Copper(Ii) Complexes Based on Isopropyl Ester Derivatives of Bis(Pyrazol-1-Yl)Acetate Ligands with Catalytic Potency in Organic Macro(Molecules) Synthesis

Copper(Ii) Complexes Based on Isopropyl Ester Derivatives of Bis(Pyrazol-1-Yl)Acetate Ligands with Catalytic Potency in Organic Macro(Molecules) Synthesis