Polymerization of supramonomers: A new way for fabricating supramolecular polymers and materials

Supramolecular polymers and materials are attracting more and more attention nowadays due to their dynamic properties such as reversibility, stimuli-responsiveness and self-healing. Conventionally, bifunctional or multi-functional monomers are first covalently synthesized, followed by the supramolecular complexation to form supramolecular polymers and materials. Recently, we have proposed the supramonomer concept to construct supramolecular polymers and materials in a different way. Supramonomers are bifunctional or multi-functional monomers fabricated by noncovalent synthesis, but can undergo traditional covalent polymerization. In this highlight article, we will summarize and discuss the fabrication of supramonomer and covalent polymerization methods of supramonomers; fabrication of multi-responsive supramolecular polymers from supramonomers; and fabrication of supramolecular materials from supramonomers. It is highly anticipated that the supramonomer concept will enrich the methodology towards supramolecular polymers and materials. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 604–609     

Electrochemical sensors of heavy metals using novel polymer-modified glassy carbon electrodes

Electroanalytical determination of heavy metals using stripping voltammetry is commonly employed and has many advantages over other methods. The sensitivity of the technique is greatly improved by employing different modified electrodes. Seven novel polymer-modified glassy carbon electrodes have been developed in this investigation for the trace analysis of heavy metals such as zinc, cadmium, lead, arsenic, and copper in formulated samples of waters by square wave stripping voltammetry. Very good responses have been observed for all the metals, while all the modified electrodes employed. The poly(3,4-ethylenedioxythiophene)-modified electrode has resulted in very low limit of detection (LOD) value. Comparison is made between literature results of LOD and the results obtained in this study. An independent atomic absorption spectroscopic analysis of the industrial wastewater sample was carried out and the results compared. The suitability of the method for practical application was ascertained by applying the procedure for the wastewater from a plating industry.     

Cellulose-based carbon—A potential anode material for lithium-ion battery

A series of hard carbons was produced by the carbonization of microcrystalline cellulose powder in the temperature range of 950–1100 °C. The properties of the carbons were characterized using elemental analysis, X-ray diffraction and N₂ and CO₂ adsorption. The effect of heat-treatment temperature (HTT), pyrolytic carbon (PC) coating and discharging mode on the lithium insertion/deinsertion behavior of the carbons was assessed in a coin-type half-cell with metal lithium cathode. Increasing cellulose HTT modifies mostly carbon porosity, the surface area (S_DFT) decreases from about 500 to 167 m² g⁻¹. It is associated with lowering the reversible C_rev and irreversible C_irr capacities, but without improving relatively low (0.72) 1st cycle coulombic efficiency. Applying constant current (CC)+constant voltage (CV) discharging mode instead of conventional CC enhances the reversible capacity by 15–18%. PC coating is effective in reducing C_irr by ∼20% with a little change of C_rev. The best capacity parameters, C_rev of 458 mA h g⁻¹ and C_irr of 139 mA h g⁻¹, were measured for PC coated 1000 °C carbon. The prolonged cycling of full-cell assembled with anode of the carbon and commercial cathode revealed that after initial 20 cycles the capacity decay (0.029 mA h/cycle) is comparable to that of commercial cell with graphite-based anode.     

Characterization and organic electric-double-layer-capacitor application of KOH activated coal-tar-pitch-based carbons: Effect of carbonization temperature

The present study reports the influence of pre-carbonization on the properties of KOH-activated coal tar pitch (CTP). The change of crystallinity and pore structure of pre-carbonized CTPs as well as their activated carbons (ACs) as function of pre-carbonization temperature are investigated. The crystallinity of pre-carbonized CTPs increases with increasing the carbonization temperature up to 600 °C, but a disorder occurs during the carbonization around 700 °C and an order happens gradually with increasing the carbonization temperatures in range of 800–1000 °C. The CTPs pre-carbonized at high temperatures are more difficult to be activated with KOH than those pre-carbonized at low temperatures due to the increase of micro-crystalline size and the decrease of surface functional groups. The micro-pores and meso-pores are well developed at around 1.0 nm and 2.4 nm, respectively, as the ACs are pre-carbonized at temperatures of 500–600 °C, exhibiting high specific capacitances as electrode materials for electric double layer capacitor (EDLC). Although the specific surface area (SSA) and pore volume of ACs pre-carbonized at temperatures of 900–1000 °C are extraordinary low (non-porous) as compared to those of AC pre-carbonized at 600 °C, their specific capacitances are comparable to each other. The large specific capacitances with low SSA ACs can be attributed to the structural change resulting from the electrochemical activation during the 1st charge above 2.0 V.     

An Efficient,Basic Resin-Mediated,One-Pot Synthesis of Dithiocarbazates Through Alcoholic Tosylates

A quick and efficient, one-pot synthesis of dithiocarbazates was accomplished in high yields by the reaction of various alcoholic tosylates of primary, secondary, and tertiary alcohols, with substituted hydrazines using an Amberlite IRA 400 (basic resin)/CS ₂ system. The reaction conditions are mild with simpler work-up procedures than previously reported methods.