Nonaqueous Interfacial Polymerization-Derived Polyphosphazene Films for Sieving or Blocking Hydrogen Gas

A series of cyclomatrix polyphosphazene films have been prepared by nonaqueous interfacial polymerization (IP) of small aromatic hydroxyl compounds in a potassium hydroxide dimethylsulfoxide solution and hexachlorocyclotriphosphazene in cyclohexane on top of ceramic supports. Via the amount of dissolved potassium hydroxide, the extent of deprotonation of the aromatic hydroxyl compounds can be changed, in turn affecting the molecular structure and permselective properties of the thin polymer networks ranging from hydrogen/oxygen barriers to membranes with persisting hydrogen permselectivities at high temperatures. Barrier films are obtained with a high potassium hydroxide concentration, revealing permeabilities as low as 9.4 × 10^-17 cm³ cm cm^-2 s^-1 Pa^-1 for hydrogen and 1.1 × 10^-16 cm³ cm cm^-2 s^-1 Pa^-1 for oxygen. For films obtained with a lower concentration of potassium hydroxide, single gas permeation experiments reveal a molecular sieving behavior, with a hydrogen permeance of around 10^-8 mol m^-2 s^-1 Pa^-1 and permselectivities of H₂/N₂ (52.8), H₂/CH₄ (100), and H₂/CO₂ (10.1) at 200 °C.

Cyclo- and Polyphosphazenes for Biomedical Applications

Cyclic and polyphosphazenes are extremely interesting and versatile substrates characterized by the presence of -P=N- repeating units. The chlorine atoms on the P atoms in the starting materials can be easily substituted with a variety of organic substituents, thus giving rise to a huge number of new materials for industrial applications. Their properties can be designed considering the number of repetitive units and the nature of the substituent groups, opening up to a number of peculiar properties, including the ability to give rise to supramolecular arrangements. We focused our attention on the extensive scientific literature concerning their biomedical applications: as antimicrobial agents in drug delivery, as immunoadjuvants in tissue engineering, in innovative anticancer therapies, and treatments for cardiovascular diseases. The promising perspectives for their biomedical use rise from the opportunity to combine the benefits of the inorganic backbone and the wide variety of organic side groups that can lead to the formation of nanoparticles, polymersomes, or scaffolds for cell proliferation. In this review, some aspects of the preparation of phosphazene-based systems and their characterization, together with some of the most relevant chemical strategies to obtain biomaterials, have been described.

Phosphazene Cyclomatrix Network-Based Polymer: Chemistry, Synthesis, and Applications

Polyphosphazenes are an inorganic molecular hybrid family with multifunctional properties due to their wide range of organic substitutes. This review intends to propose the basics of the synthetic chemistry of polyphosphazene, describing for researchers outside the field the basic knowledge required to design and prepare polyphosphazenes with desired properties. A special emphasis is placed on recent advances in chemical synthesis, which allow not only the synthesis of polyphosphazenes with controlled molecular weights and polydispersities but also the synthesis of novel branched designs and block copolymers. We also investigated the synthesis of polyphosphazenes using various functional materials. This review aims to assist researchers in synthesizing their specific polyphosphazene material with unique property combinations, with the hope of stimulating further research and even more innovative applications for these highly interesting multifaceted materials.

On Hosoya Polynomial and Subsequent Indices of C4C8(R) and C4C8(S) Nanosheets

Chemical structures are mathematically modeled using chemical graphs. The graph invariants including algebraic polynomials and topological indices are related to the topological structure of molecules. Hosoya polynomial is a distance based algebraic polynomial and is a closed form of several distance based topological indices. This article is devoted to compute the Hosoya polynomial of two different atomic configurations (C4C8(R) and C4C8(S)) of C4C8 Carbon Nanosheets. Carbon nanosheets are the most stable, flexible structure of uniform thickness and admit a vast range of applications. The Hosoya polynomial is used to calculate distance based topological indices including Wiener, hyper Wiener and Tratch–Stankevitch–Zafirov Indices. These indices play their part in determining quantitative structure property relationship (QSPR) and quantitative structure activity relationship (QSAR) of chemical structures. The three dimensional presentation of Hosoya polynomial and related distance based indices leads to the result that though the chemical formula for both the sheets is same, yet they possess different Hosoya Polynomials presenting distinct QSPR and QSAR corresponding to their atomic configuration.

Investigation of the mechanism of small size effect in carbon-based supercapacitors

A small size effect could be conducive to enhancing the electrochemical performance, while the mechanism by which they also increase the capacitance for carbon electrode materials has not been established. Here, ultrasmall polyacrylonitrile particles with controllable sizes are supported on poly(ionic liquid)s microspheres (PILMs/PAN) by epitaxial polymerization growth strategy. Unlike traditional subtraction formulas in developing a porous architecture, we report on the synthesis of creating numerous micro/mesopores in carbon materials by addition theorem, and thus making for the perfection of packing density, which has not been reported yet. As an example, PILMC/PAN-L with a well-balanced specific surface area of 875.38 m² g^-1 and packing density of 1.05 g cm^-3 demonstrated gravimetric and volumetric capacitances of 309 F g^-1 and 324.45 F cm^-3 at 0.5 A g^-1, showing good rate performance and stable cyclability. Moreover, the underlying mechanism is thoroughly developed using multiple electrochemical methods. On this basis, this work would afford avenues to further enhancing the electrochemical performance, especially in exploring advanced carbon materials.