Surface- and Redox-Active Multifunctional Polyphenol-Derived Poly(ionic liquid)s: Controlled Synthesis and Characterization

Integrating Antioxidant Functionality into Polymer Materials: Fundamentals, Strategies, and Applications

While antioxidants are widely known as natural components of healthy food and drinks or as additives to commercial polymer materials to prevent their degradation, recent years have seen increasing interest in enhancing the antioxidant functionality of newly developed polymer materials and coatings. This paper provides a critical overview and comparative analysis of multiple ways of integrating antioxidants within diverse polymer materials, including bulk films, electrospun fibers, and self-assembled coatings. Polyphenolic antioxidant moieties with varied molecular architecture are in the focus of this Review, because of their abundance, nontoxic nature, and potent antioxidant activity. Polymer materials with integrated polyphenolic functionality offer opportunities and challenges that span from the fundamentals to their applications. In addition to the traditional blending of antioxidants with polymer materials, developments in surface grafting and assembly via noncovalent interaction for controlling localization versus migration of antioxidant molecules are discussed. The versatile chemistry of polyphenolic antioxidants offers numerous possibilities for programmed inclusion of these molecules in polymer materials using not only van der Waals interactions or covalent tethering to polymers, but also via their hydrogen-bonding assembly with neutral molecules. An understanding and rational use of interactions of polyphenol moieties with surrounding molecules can enable precise control of concentration and retention versus delivery rate of antioxidants in polymer materials that are critical in food packaging, biomedical, and environmental applications.

Macromolecular Engineering of Poly(catechol) Cathodes towards High-Performance Aqueous Zinc-Polymer Batteries

Aqueous zinc-polymer batteries (AZPBs) comprising abundant Zn metal anode and redox-active polymer (RAP) cathodes can be a promising solution for accomplishing viable, safe and sustainable energy storage systems. Though a limited number of RAPs have been successfully applied as organic cathodes in AZPBs, their macromolecular engineering towards improving electrochemical performance is rarely considered. In this study, we systematically compare performance of AZPB comprising Zn metal anode and either poly(catechol) homopolymer (named P(4VC)) or poly(catechol) copolymer (named P(4VC86-stat-SS14)) as polymer cathodes. Sulfonate anionic pendants in copolymer not only rendered lower activation energy and higher rate constant, but also conferred lower charge-transfer resistance, as well as facilitated Zn2+ mobility and less diffusion-controlled current responses compared to its homopolymer analogue. Consequently, the Zn||P(4VC86-stat-SS14) full-cell exhibits enhanced gravimetric (180 versus 120 mAh g-1 at 30 mg cm-2) and areal capacity (5.4 versus 3.6 mAh cm-2 at 30 mg cm-2) values, as well as superior rate capability both at room temperature (149 versus 105 mAh g-1 at 150 C) and at -35 °C (101 versus 35 mAh g-1 at 30 C) compared to Zn||P(4VC)100. This overall improved performance for Zn||P(4VC86-stat-SS14) is highly encouraging from the perspective applying macromolecular engineering strategies and paves the way for the design of advanced high-performance metal-organic batteries.

Linear Main-Chain 1,2,4-Triazolium Poly(ionic liquid)s: Single-Step Synthesis and Stabilization of Cellulose Nanocrystals

Linear main-chain 1,2,4-triazolium-based poly(ionic liquid)s (PILs) were synthesized in this contribution. The polymerization process is experimentally very simple and involves only a single-step polycondensation of a commercially available monomer in DMSO as solvent at 120 °C. Their thermal stability and solubility were analyzed in terms of different counteranions. Due to the ease of this synthetic route, it was readily applied to graft onto sulfonated cellulose nanocrystals (CNCs) via a one-step in situ polymerization. The as-synthesized PIL@CNC hybrid colloids exhibit adaptive dispensability in water and organic solvents.

Ultrasound-induced synthesis of an imidazolium based poly(ionic liquid) in an aqueous media: A structural, thermal and morphological study

Here we describe an efficient and rapid way for the polymerization of the 3-Octyl-1-vinylimidazolium Bromide using ultrasonic irradiation. This way promoted high dispersion polymerization using a water-soluble free radical initiator namely 4,4'-Azobis (4-cyanopentanoic acid) and free of dispersant. The ionic liquid monomer was prepared via quaternization of 1-vinylimidazole with octyl bromide also promoted by ultrasound. The polymerization rates were compared with a conventional heating method and appeared to be higher in the case of the ultrasound method within a short reaction time. The structural/morphological features and thermal properties of the obtained products were determined by different analytical techniques such as (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electronic microscopy (SEM, TEM), Fourier transform infrared spectroscopy (FTIR) and NMR Spectroscopy (¹H and ¹³C NMR). The morphology and the thermal behavior of the obtained poly(ionic liquid) were investigated and discussed. The results indicated that self-assembled nanospherical particles of 30-80 nm in diameter were obtained through the ultrasound method, while on the other hand; worm-like/cylindrical agglomerated nanoparticles with irregular sizes 50-300 nm in diameter were obtained via the classical heating method.

Catechol End-Functionalized Polylactide by Organocatalyzed Ring-Opening Polymerization

There is a great interest in incorporating catechol moieties into polymers in a controlled manner due to their interesting properties, such as the promotion of adhesion, redox activity or bioactivity. One possibility is to incorporate the catechol as end-group in a polymer chain using a functional initiator by means of controlled polymerization strategies. Nevertheless, the instability of catechol moieties under oxygen and basic pH requires tedious protection and deprotection steps to perform the polymerization in a controlled fashion. In the present work, we explore the organocatalyzed synthesis of catechol end-functional, semi-telechelic polylactide (PLLA) using non-protected dopamine, catechol molecule containing a primary amine, as initiator. NMR and SEC-IR results showed that in the presence of a weak organic base such as triethylamine, the ring-opening polymerization (ROP) of lactide takes place in a controlled manner without need of protecting the cathechol units. To further confirm the end-group fidelity the catechol containing PLLA was characterized by Cyclic Voltammetry and MALDI-TOF confirming the absence of side reaction during the polymerization. In order to exploit the potential of catechol moieties, catechol end-group of PLLA was oxidized to quinone and further reacted with aliphatic amines. In addition, we also confirmed the ability of catechol functionalized PLLA to reduce metal ions to metal nanoparticles to obtain well distributed silver nanoparticles. It is expected that this new route of preparing catechol-PLLA polymers without protection will increase the accessibility of catechol containing biodegradable polymers by ROP.

Consecutive loss of two benzyl radicals from the [M + Na]+ adduct ions of pyrogallol tribenzyl ether and its derivatives

The electrospray ionization-collision-induced dissociation mass spectra of nine pyrogallol tribenzyl ethers, 2-10, and a catechol dibenzyl ether, 11, that bear various functional groups or larger structural extensions have been studied with respect to the occurrence of a highly characteristic consecutive loss of two benzyl radicals from the sodiated molecular ions, [M + Na]⁺. It is shown that this specific fragmentation reaction strongly dominates other fragmentation routes, such as loss of carbon monoxide, formaldehyde and water. In addition, elimination of benzaldehyde occurs as a minor fragmentation channel in most cases. In contrast to these aryl-benzyl ethers, the consecutive two-fold loss of C₇H₇^• is suppressed in the [M + Na]⁺ ions of dibenzyl ethers derived from multiply benzylated gallocatechin and catechin, where the elimination of benzyl alcohol prevails the primary fragmentation almost completely. The secondary fragmentation of the [M + Na]⁺ ions, which also comprises the two-fold loss of C₇H₇^•, as well as a remarkable primary fragmentation of a flavene-based congener leading to particularly stable sodium-free chromylium product ions is also presented. † Deceased.

A family of linear phenolic polymers with controlled hydrophobicity, adsorption and antioxidant properties

The synthesis of a series of antioxidant polymers with varied capability to scavenge radicals and alter the wettability of surfaces is reported.

Bis(formylphenolato)cobalt(II)-Mediated Alternating Radical Copolymerization of tert-Butyl 2-Trifluoromethylacrylate with Vinyl Acetate

The organometallic-mediated radical polymerization (OMRP) of vinyl acetate (VAc) and its OMR copolymerization (OMRcoP) with tert-butyl 2-trifluoromethylacrylate (MAF-TBE) mediated by Co(SAL)₂ (SAL = 2-formylphenolato or deprotonated salicylaldehyde) produced relatively well-defined PVAc and poly(VAc-alt-MAF-TBE) copolymers at moderate temperature (<40 °C) in bulk. The resulting alternating copolymer was characterized by ¹H-, 13C- and 19F-nuclear magnetic resonance (NMR) spectroscopies, and by size exclusion chromatography. The linear first-order kinetic plot, the linear evolutions of the molar mass with total monomer conversion, and the relatively low dispersity (Đ~1.55) of the resulting copolymers suggest that this cobalt complex provides some degree of control over the copolymerization of VAc and MAF-TBE. Compared to the previously investigated cobalt complex OMRP mediators having a fully oxygen-based first coordination sphere, this study emphasizes a few peculiarities of Co(SAL)₂: a lower ability to trap radical chains as compared to Co(acac)₂ and the absence of catalytic chain transfer reactions, which dominates polymerizations carried in the presence of 9-oxyphenalenone cobalt derivative.

Bioinspired Redox-Active Catechol-Bearing Polymers as Ultrarobust Organic Cathodes for Lithium Storage

Redox-active catechols are bioinspired precursors for ortho-quinones that are characterized by higher discharge potentials than para-quinones, the latter being extensively used as organic cathode materials for lithium ion batteries (LIBs). Here, this study demonstrates that the rational molecular design of copolymers bearing catechol- and Li⁺ ion-conducting anionic pendants endow redox-active polymers (RAPs) with ultrarobust electrochemical energy storage features when combined to carbon nanotubes as a flexible, binder-, and metal current collector-free buckypaper electrode. The importance of the structure and functionality of the RAPs on the battery performances in LIBs is discussed. The structure-optimized RAPs can store high-capacities of 360 mA h g^-1 at 5C and 320 mA h g^-1 at 30C in LIBs. The high ion and electron mobilities within the buckypaper also enable to register 96 mA h g^-1 (24% capacity retention) at an extreme C-rate of 600C (6 s for total discharge). Moreover, excellent cyclability is noted with a capacity retention of 98% over 3400 cycles at 30C. The high capacity, superior active-material utilization, ultralong cyclability, and excellent rate performances of RAPs-based electrode clearly rival most of the state-of-the-art Li⁺ ion organic cathodes, and opens up new horizons for large-scalable fabrication of electrode materials for ultrarobust Li storage.