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Self‐healing polymer coatings have gained increased attention as a pathway for regenerating the inherent properties of surface following mechanical, physical or chemical damages. In most cases, the adhesion between the polymer coating layer and the substrate is driven by physical interactions. For some applications, immersing the polymer coating under water or exposing the coating to organic solvent vapors will undoubtedly lead to the coating delamination. One way to circumvent this issue is to attach the coating to the substrate via covalent bonds. However, this process will impede the self‐healing feature of the polymer coating due to the confinement of the volume change of the polymer to one dimension. Herein, surface‐attached metallo‐supramolecular polymer conetwork coatings are reported. The ability of the polymer conetworks to swell in organic solvent while maintaining their dimensional stability combined with reversible supramolecular cross‐links based on metal complexes enables the design of scratch‐healing polymer coatings. These metallo‐supramolecular polymer conetworks are prepared in a three‐step UV‐initiated polymerization reaction starting from the poly(pentafluorophenyl acrylate)‐l‐polydimethylsiloxane (PPFPA‐l‐PDMS)‐activated ester covalently attached to the substrate. Reacting the polymer conetwork coating with the 4‐(2‐aminoethyl)pyridine and cross‐linking the pyridine phases with ZnCl2 lead to the poly(N‐(2(pyridin‐4‐yl)ethyl)acrylamide‐Zn(II))‐l‐polydimethylsiloxane (PNP4EA‐Zn(II)‐l‐PDMS) polymer conetwork coatings with scratch‐healing ability. [ABSTRACT FROM AUTHOR]

The current challenge in self‐healing materials resides in the design of materials which exhibit improved mechanical properties and self‐healing ability. The design of phase‐separated nanostructures combining hard and soft phases represents an attractive approach to overcome this limitation. Amphiphilic polymer conetworks are nanostructured materials with robust mechanical properties, which can be tailored by tuning the polymer composition and chemical functionality. This article highlights the design of phase‐separated nanostructured polymers from metallo‐supramolecular amphiphilic polymer conetworks, and their application for self‐healing surfaces. The synthesis of poly(N‐(pyridin‐4‐yl)acrylamide)‐l‐polydimethylsiloxane polymer conetworks from the poly(pentafluorophenyl acrylate)‐l‐polydimethylsiloxane activated ester is presented. Loading of ZnCl2 salt into the phase‐separated polymer conetwork strengthens the network by cross‐linking the poly(N‐(pyridin‐4‐yl)acrylamide) phases, while offering reversible interactions needed for self‐healing ability. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the synthesis and characterization of triple‐shape and two‐way shape‐memory effect of novel poly(ester‐urethane)s (PURs) made of a poly(ε‐caprolactone) (PCL) and poly(ω‐pentadecalactone) (PPDL) segments and N,N‐bis(2‐hydroxyethyl)cinnamide (BHECA) monomer by reactive extrusion (REx) is reported. PCL and PPDL are chosen as semicrystalline segments because of their inherent ability to undergo tensile elongation upon cooling, as prerequisite for the two‐way shape‐memory effect. BHECA is used as the “cross‐linker” due to its ability to participate in reversible [2+2] cycloaddition reaction and to mainly maintain the crystalline features of semicrystalline precursors within these PURs. This novel simple strategy is considered extremely versatile and adaptive because of the possibility to vary crystallizable segments and coupling agents, thus paving the way to the design of a multitude of triple (or more) shape‐memory polymers with two‐way behavior. Feasibility with PURs containing PCL, PPDL, and BHECA is demonstrated by adjusting the shape‐memory behavior (one and two‐way effects), and studying the structure–property relationships of the resulting PURs by DSC, DMTA, and 2D wide angle X‐ray scattering analyses while varying the weight composition of the two semicrystalline segments. [ABSTRACT FROM AUTHOR]

In this work, a systematic study on the humidity-activated shape memory properties of dual-responsive shape memory bionanocomposites with both humidity- and thermally-activated shape memory effects is reported. The study is performed through humidity-mechanical cycles in an Instron machine with a temperature chamber equipped with an ultrasonic humidity generator. In particular, the bionanocomposites studied are based on blends of ethylene-vinyl acetate (EVA) and thermoplastic starch reinforced with natural bentonite. In our previous work, thermomechanical cycles are performed by using EVA-induced crystallization and a preliminary humidity-activated shape memory test is designed. Herein, the shape memory results of both blends and their nanocomposites reflect the very good ability to humidity-activated recover of the initial shape with values higher than 80%. Moreover, the ability to fix the temporary shape of this systems is very good, especially when nanofillers are added. The compatibilizer effect of natural bentonite is demonstrated by means of different techniques such as scanning emission microscopy and mapping by confocal Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Conjugated poly(3-hexylthiophene) copolymer derivatives containing 10% appended porphyrin moieties are prepared using a supramolecular approach toward applications in organic electro­nics. The self-assembled polythiophene-porphyrin copolymers are synthesized by coordination of the porphyrinato central zinc ions to the imidazole-functionalized polythiophene side chains. Evidence for the self-assembly process is provided by 1H NMR spectroscopy, single crystal X-ray diffraction, and optical absorption studies on model compounds. The polythiophene-porphyrin copolymers show an extended absorption window in the region of 420-650 nm due to the contribution of the porphyrin. Photoluminescence studies indicate concentration-dependent energy transfer from P3HT to the porphyrin. Preliminary photovoltaic studies are performed by combining the polythiophene-porphyrin copolymers with PC61BM in the photo­active layer of bulk heterojunction organic solar cells. [ABSTRACT FROM AUTHOR]

To date, the controlled preparation of cyclic polymers is mainly achieved using click ligation strategies. The light-induced Diels-Alder click coupling has recently been shown to function as an attractive catalyst-free alternative to the copper-catalyzed alkyne-azide cycloaddition. However, the need for a light emitting system limits its applicability. To overcome this drawback, a sunlight-induced Diels-Alder reaction as an efficient route for the preparation of cyclic aliphatic polyesters in high yields and purity based on the same chemistry is demonstrated in the present contribution. The versatility and robustness of the proposed strategy against divergent atmospheric conditions is demonstrated. In light of the simplicity of the strategy presented here, it is suggested that the sunlight-induced Diels-Alder click-cyclization is a world-wide transposable process. [ABSTRACT FROM AUTHOR]

We show how styrene-ethylene-propylene-styrene (SEPS) triblock copolymer uniquely reduces the electrical percolation threshold after matrix crystallization of conductive nanocomposites based on high viscosity HDPE with low amounts of pristine multiwall carbon nanotubes (CNT). Rheo-dielectric and Flash DSC techniques are used to demonstrate that SEPS interferes with the nucleation ability of CNT on HDPE crystallization in a way that favors contacts between the nanotubes after crystallization as well as it improves CNT dispersion. [ABSTRACT FROM AUTHOR]

Imidazolium end-functionalized poly(butyl acrylate) and polystyrene (co)polymers (Im-PnBuA, Im-PSty, and Im-PnBuA- b-PSty are synthesized via ATRP. The controlled character of the polymerization reactions is highlighted by SEC and MALDI-TOF MS analyses. Subsequently, the polymers are tested as dispersing/compatibilizing agents for CNTs in polymer matrices. When CNTs are challenged with a mixture of Im-PnBuA and Im-PSty, the CNTs are mainly located in the PnBuA phase. In contrast, the Im-PnBuA- b-PSty block copolymer enables CNT confinement in the PSty phase. By selecting the proper ω-imidazolium polymer, it is possible to direct the CNT confinement toward a specific polymer phase within polymer mixtures. [ABSTRACT FROM AUTHOR]

This paper reports the preparation, characterization, and performance of three low viscosity fully bio‐based benzoxazine resins synthesized from bio‐based furfurylamine, paraformaldehyde, and three new enzymatic originated diphenols obtained through a sustainable and highly selective lipase‐catalyzed enzymatic process from p‐coumaric acid, and three bio‐based diols (propanediol, butanediol, and isosorbide, respectively). The enzymatic method is used for the first time, to the authors' knowledge, to design specific diphenolic structures dedicated to the preparation of benzoxazine thermosetting resins whose precursors exhibit easy handling within a wide processing window (from room temperature up to 200 °C). The resulting cross‐linked materials present high glass transition temperature (Tg > 200 °C) and inherent charring ability upon pyrolysis (≈50 wt% at 1000 °C). These results open a valuable and new pathway to develop enhanced benzoxazines and bring them new properties. Lipase‐catalyzed enzymatic process is used for the first time, to the authors' knowledge, to design specific diphenolic structures dedicated to the preparation of benzoxazine thermosets from fully bio‐based renewable resources. The resulting benzoxazine precursors exhibit low viscosity and easy handling within a wide processing window. After curing, the materials obtained present high glass transition temperature and inherent charring ability upon pyrolysis. [ABSTRACT FROM AUTHOR]