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The problem of plastic waste in the environment calls for the development of new polymeric materials designed specifically for easy recycling at the end of their life cycle. Herein, a green polymer system comprising a series of necklace‐shaped polydimethylsiloxanes bearing anthracene dimer units is developed. The polymers have low environmental impact and are easily recycled. Further, their flexibility and glass transition temperatures are easy to control. These necklace‐shaped inorganic polymers are synthesized by photopolymerizing (dimerizing) anthracene‐terminated oligo‐dimethylsiloxane monomers. A key achievement of the present work is the successful chemical recovery of the monomers from the polymers through thermal depolymerization, enabling monomer–polymer recycling. By applying equilibrium polymerization with base catalysts, monomers with a controlled distributed chain length are synthesized from monomers with a constant chain length. The necklace‐shaped polymers synthesized from these randomized monomers have amorphous structures and readily form transparent films. It is possible to modulate the thermal and mechanical properties of the polymers by controlling the average chain length of the polydimethylsiloxane between the anthracene dimers. This investigation presents a method for the synthesis and cyclic utilization of polymer materials with a wide range of applications, including plastics and elastomers. [ABSTRACT FROM AUTHOR]

The reversible photo‐induced [4+4] cycloaddition reaction of anthracene enables multiple cycles of dimerization and scission, allowing phototunable linkage of molecular fragments for the synthesis of polymer scaffolds. New functional materials ranging from hydrogels to shape‐memory polymers were designed from anthryl‐polymer systems because of their diverse photochemical reactivity and responsiveness. Light as an external stimulus allows for the remote and precise spatiotemporal control of materials without the need for additional reagents. Depending on how the photoreactive anthracene moieties were introduced, the interaction of anthryl‐polymer systems with light results in various processes such as polymerization, cyclization, and cross‐linking. Structural modifications of anthracene derivatives could shift their absorption from the ultraviolet to the visible light region, widening their range of applications including biologically relevant studies. These applications are further diversified and enhanced by the reversibility of the dimerization reaction using light and heat as stimuli. In this review, current developments in the synthesis and photodimerization of anthracene‐containing polymers and their emerging applications in the fabrication of new materials are discussed. [ABSTRACT FROM AUTHOR]

In this paper we present a convenient and scalable synthesis of 1‐(methylamino)anthracene, which is a potent building block for the construction of photoresponsive materials. With this structural motif we have synthesized an anion receptor bearing two anthracene groups. Interaction of a chloride anion with the anthracene moieties increases the association constant. Photocycloaddition allows to obtain a single macrocyclic receptor, which exhibits higher binding constants due to the macrocyclic effect. Facile synthesis provides a novel anthracene‐based amine, which acts as a versatile building block for the construction of photoswitchable receptors. Incorporation of this structural motif into dipicolinic amide provides a photoresponsive anion receptor. Upon irradiation with 360 nm light, cycloaddition occurs to yield macrocyclic receptors with higher affinities for anions. [ABSTRACT FROM AUTHOR]

Abstract: A trifunctional, partially fluorinated anthracene‐substituted triptycene monomer was spread at an air/water interface into a monolayer, which was transformed into a long‐range‐ordered 2D polymer by irradiation with a standard UV lamp. The polymer was analyzed by Brewster angle microscopy, scanning tunneling microscopy measurements, and non‐contact atomic force microscopy, which confirmed the generation of a network structure with lattice parameters that are virtually identical to a structural model network based on X‐ray diffractometry of a closely related 2D polymer. The nc‐AFM images highlight the long‐range order over areas of at least 300×300 nm2. As required for a 2D polymer, the pore sizes are monodisperse, except for the regions where the network is somewhat stretched because it spans over protrusions. Together with a previous report on the nature of the cross‐links in this network, the structural information provided herein leaves no doubt that a 2D polymer has been synthesized under ambient conditions at an air/water interface. [ABSTRACT FROM AUTHOR]

Anthracene dimer diols having very different thermal stabilities have been incorporated in polyurethane networks. The thermal de-crosslinking of these networks was shown to be dependent on the anthracene dimer used, allowing tunable thermal degradation. This scission was studied using (HR-MAS) NMR, DSC and rheometry. The tunable thermal decrosslinking was validated as a technique to easily remove the coatings at their end-of-life. The UV irradiation of the thermally degraded materials allows for recuring the coatings to materials having similar properties. By simultaneous irradiation and heating of (partially) reversibly cross-linked networks, the networks were able to relief internal stress and adopt a new permanent shape. [ABSTRACT FROM AUTHOR]

Abstract: The assembly of supramolecular polymers from a phosphodiester‐linked dimeric anthracene is described. AFM and TEM imaging reveals that the supramolecular polymers self‐assemble into nanotubes in water. Subsequent photodimerization experiments indicate that the supramolecular polymerization occurs via end‐to‐end stacking rather than an interdigitation arrangement of the building blocks. [ABSTRACT FROM AUTHOR]

A combination of light-induced [4+4] cycloaddition polymerization and activated ester substitution reaction is demonstrated as a new method to obtain novel polymeric structures. Bis-anthracene functionalized compound involving perfluorophenyl ester moiety namely, bisanthracenyl-PFPE, is prepared by an esterification reaction, then polymerized under UV light irradiated at 365 nm. The resulting polymer is reacted with a variety of amine compounds namely allylamine, benzylamine, furfurylamine, and propargylamine, under mild conditions. Quantitative conversions of perfluorophenyl ester groups into the respective amide groups as well as the thermal behaviors of all polymers are revealed by using various spectroscopic measurements such as Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography, NMR, and differential scanning calorimetry. [ABSTRACT FROM AUTHOR]

Highlights: [•] We have modified EBA copolymers with anthracene chromophores by reactive extrusion. [•] Photodimerization of anthracene takes place in the solid-state upon UV irradiation. [•] Photocleavage of anthracene dimers occurs partially under nitrogen. [•] DMTA and mechanical properties were studied before and after UV irradiation. [•] Photocrosslinking of EBA by anthracene dimerization improves mechanical properties. [Copyright &y& Elsevier]

We designed a straightforward avenue to obtain single-chain polymeric nanoparticles using photoactive 4-armed star copolymers which are synthesized by a controlled radical polymerization strategy. Constructed star copolymers undergo intramolecular crosslinking upon Ultra-violet irradiation in dilute conditions (c polymer = 0.5 mg mL−1). Resulting crosslinked products have smaller particle size and higher glass transition temperature compared to their star copolymer analogues. Polymeric nanoparticles exhibit globular structure and more compact morphology as expected. The formation of star polymers and their single-chain products were characterized by size exclusion chromatography (SEC), SEC with UV, multi-angle light scattering (MALS), proton nuclear magnetic resonance spectroscopy (1H NMR), diffusion ordered spectroscopy (DOSY), dynamic light scattering (DLS), transmission electron microscopy (TEM), Ultra-violet and fluorescence spectroscopies. Single-chain nanoparticle formation from 4-armed star copolymers via photoinduced intramolecular crosslinking of pendant anthracene species is presented with narrow dispersity values. Photodimerization of side-chain anthracene motifs causes collapsing polymer chains upon UV-light exposure. Resulting single-chain polymeric nanoparticles show fluorescence properties owing to non-dimerized anthracene functionalities in the polymer structure as well. Image 1 • Star polymers collapse under UV irradiation. • Side-chain anthracene motifs causes collapsing of polymer chains of star polymers upon UV-light. • Intramolecularly crosslinked nanoparticles were formed by photodimerization in dilute regime. [ABSTRACT FROM AUTHOR]

Microporous ladder polymers (MLPs) represent a beneficial combination of porosities and processability for advanced separation and catalysis. Yet MLPs synthesis is halted by tedious condensation reactions, excessive catalysts and limited choices of monomers. The work reports the first example of room temperature synthesis of MLPs (PAnTB) through photopolymerization of contorted bisanthracene monomers under 365 nm light irradiation, being catalyst-free and atom-economy. PAnTB highlight intrinsically microporous properties (specific surface area: 554 m2 g−1) and efficient photosensitization for the generation of singlet oxygen. This work opens the door to light-induced synthesis of MLPs with enriched monomer structures and functionalities, such as the metal-free degradation of organic contaminants using PAnTB alone under visible-light. Microporous ladder polymers were synthesized by room temperature photopolymerization for the first time, featuring high specific surface area and photosensitization for the generation of singlet oxygen under visible-light irradiation. Unlabelled Image [ABSTRACT FROM AUTHOR]

The synthesis of a promising 2D polymer uses the double decker rotor‐shaped monomer 1, containing three anthracene moieties. To accelerate the development of the field of 2D polymers, this monomer was selected for scale‐up that would allow its synthesis to be performed on the kg scale under technical conditions. This goal was achieved in collaboration with Polymaterials AG, Kaufbeuren, Germany. Not only was the synthetic route shortened, but each and every aspect of the remaining steps was streamlined so as to render them applicable to technical conditions. This involved the entire sequence to be adapted to metal instead of glass reactors and to a number of safety and toxicity concerns. Additionally, not only the utilization of the reactors had to meet strict efficiency requirements, but also the work‐up procedures had to be facile. The whole sequence was then tested for feasibility under realistic conditions at Polymaterials AG. While this test afforded 130 g of monomer 1, it has the clear potential for the kg scale, supposed the safety equipment for the hydrogen evolution for the conversion of compound 2a – 3 is available. [ABSTRACT FROM AUTHOR]

Synthetic covalent monolayer sheets and their subclass, two-dimensional polymers are of particular interest in materials science because of their special dimensionality which renders them very different from any bulk matter. However, structural analysis of such entities is rather challenging, and there is a clear need for additional analytical methods. The present study shows how tip-enhanced Raman spectroscopy (TERS) can be performed on monomer monolayers and the covalent sheets prepared from them by [4 + 4]-cycloaddition to explore rather complex structural and mechanistic issues. TERS is a surface analytical method that combines the high lateral resolution of scanning probe microscopy (SPM) with a greatly enhanced Raman scattering intensity. The high spatial resolution (<60 nm) and the significantly improved sensitivity (contrast factor of >4000) compared to confocal Raman microscopy provides new insights into the formation of this new and exciting material, namely significant consumption of the reactive units (anthracenes) and exclusion of the alternative [4 + 2]-cycloaddition. Moreover, due to the high lateral resolution, it was possible to find a first spectroscopic hint for step growth as the dominant mechanism in the formation of these novel monolayer sheets. In addition, TERS was used to get first insights into the phase behavior of a comonomer mixture.