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Controlled radical polymerization corresponds to variety of synthetic strategies that aim the generation of precise macromolecular architectures. Iodine transfer polymerization (ITP) is one of the oldest methods to conduct controlled radical polymerization; however, it seems to have lost visibility compared to other popular techniques. It relies on utilization of iodine species in reversible deactivation kinetics, and it has some significant advantages compared to other methods. Its simplicity, minimized toxicity, metal‐free nature, no coloring on final product, and ease of purification provide widespread applicability, even in industry. In this perspective, the basics of ITP are re‐introduced, and emerging technologies (heterophase polymerization, photoinitiation, and sustainability) in ITP are discussed. [ABSTRACT FROM AUTHOR]

Benign polymerization routes offer new perspectives in current polymer technology. Especially for automated or continuous flow synthesis of polymers, new devices and principles have to be considered by the means of minimizing addition or separation sequences as well as the type of a polymer initiation. Near‐UV and visible light‐induced polymerization utilizing metal‐free semiconductor polymeric carbon nitride (pCN) as heterogeneous photocatalyst was a first step into this direction. Moving from heterogeneous powder catalysis (which still requests catalyst separation) to surface photocatalysis via coating glass tubes or vials with pCN thin films is presented. Performance and effectivity of those photoactive reactors are proven by free radical photopolymerization of variety of monomers. Reusability of vials is demonstrated via reversible addition‐fragmentation chain‐transfer polymerization‐assisted block copolymer synthesis. This strategy eliminates the necessity of adding or removing initiators, works at room temperature, and offers a platform for cheap and effective polymer synthesis at the age of automated synthesis. [ABSTRACT FROM AUTHOR]

Conductive polymers find key applications ranging from optoelectronics and OLEDs to conductive composite materials. The synthesis of conductive polymers from monomers, such as thiophene derivatives, pyrroles and aniline, mainly relies on oxidative polymerization, and the processing of so‐formed (insoluble) polymers is a major issue that needs to be addressed. In the present work, oxidative photopolymerization of 3,4‐ethylenedioxythiophene (EDOT) by visible light employing the metal‐free semiconductor graphitic carbon nitride (g‐CN) is presented. Two main reaction pathways based on g‐CN content are described, and the formation of processable oligo‐EDOT is demonstrated. [ABSTRACT FROM AUTHOR]

The year 2020 marks the 100th anniversary of the first article on polymerization, published by Hermann Staudinger. It is Staudinger who realized that polymers consist of long chains of covalently linked building blocks. Polymers have had a tremendous impact on the society ever since this initial publication. People live in a world that is almost impossible to imagine without synthetic polymers. But what does the future hold for polymer science? In this article, the editors and advisory board of Macromolecular Chemistry and Physics reflect on this question. [ABSTRACT FROM AUTHOR]

Series of diblock copolymers of the type poly(styrene-b-4-vinylpyridine) (PS-P4VP) are synthesized via anionic polymerization. In toluene, a selective solvent for the PS block, well-defined micelles with narrow molecular weight distribution are formed. Size and shape of the micelles are characterized by static (SLS) and dynamic light scattering (DLS), and electron microscopy (EM). The aggregation number Z exhibits a scaling relation Z∝N1.93P4VPN-0.79PS, where N is the degree of polymerization of each block. We find this behavior close to a Z∼N2AN-0.8B limiting scaling law which appears to be a characteristic of strongly segregated diblock and triblock copolymer systems as well as low molecular weight cationic, anionic, and nonionic surfactants. A simple micellization model is developed that predicts aggregation numbers of surfactants, diblock, triblock, and graft copolymers. The corona dimension Dh as measured by DLS scales as Dh∝Z0.21N0.63PS in agreement with the theoretical prediction D∼Z1/5N3/5B for starlike molecules in good solvents. Neither unimers nor a critical micelle concentration are observed. Instead at very low concentrations the excess scattering intensity increases due to the formation of large particles. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric carbon nitride (PCN), in either triazine or heptazine form, has been regarded as a promising metal‐free, environmentally benign, and sustainable photocatalyst for solar hydrogen production. However, PCN in most cases only exhibits moderate activity owing to its inherent properties, such as rapid charge carrier recombination. Herein we present a triazine–heptazine copolymer synthesized by simple post‐calcination of PCN in eutectic salts, that is, NaCl/KCl, to modulate the polymerization process and optimize the structure. The construction of an internal triazine–heptazine donor–acceptor (D‐A) heterostructure was affirmed to significantly accelerate interface charge transfer (CT) and thus boost the photocatalytic activity (AQY=60 % at 420 nm). This study highlights the construction of intermolecular D‐A copolymers in NaCl/KCl molten salts with higher melting points but in the absence of lithium to modulate the chemical structure and properties of PCN. [ABSTRACT FROM AUTHOR]

Abstract: Energy efficient buildings require materials with a low thermal conductivity and a high fire resistance. Traditional organic insulation materials are limited by their poor fire resistance and inorganic insulation materials are either brittle or display a high thermal conductivity. Herein we report a mechanically resilient organic/inorganic composite aerogel with a thermal conductivity significantly lower than expanded polystyrene and excellent fire resistance. Co‐polymerization and nanoscale phase separation of the phenol‐formaldehyde‐resin (PFR) and silica generate a binary network with domain sizes below 20 nm. The PFR/SiO2 aerogel can resist a high‐temperature flame without disintegration and prevents the temperature on the non‐exposed side from increasing above the temperature critical for the collapse of reinforced concrete structures. [ABSTRACT FROM AUTHOR]

To extend fossil oil supplies, sustainable feed stocks for the production of useful reagents and polymers should be harnessed. In this regard, chemicals derived from plants are excellent candidates. While the vast majority of plant sources used for polymer science only contain C x H y O z , alkaloids such as caffeine, nicotine, and theophylline possess nitrogen functionality that can provide new functions for bioderived polymers and their synthesis. In this context, the chemistry of theophylline, a natural product found in chocolate and tea, is exploited to create a cationic 'poly(theophylline)' in a straightforward fashion for the first time. This work demonstrates how this new polymer can be synthesized and used for the creation of narrowly disperse cationic microspheres. [ABSTRACT FROM AUTHOR]

Polymer-derived carbon aerogels can be obtained by direct polymerization of monomers under hypersaline conditions using inorganic salts. This allows for significantly increased mechanical robustness and avoiding special drying processes. This concept was realized by conducting the polymerization of phenol-formaldehyde (PF) in the presence of ZnCl2 salt. Afterwards, the simultaneous carbonization and foaming process conveniently converts the PF monolith into a foam-like carbon aerogel. ZnCl2 plays a key role, serving as dehydration agent, foaming agent, and porogen. The carbon aerogels thus obtained are of very low density (25 mg cm−3), high specific surface area (1340 m2 g−1), and have a large micro- and mesopore volume (0.75 cm3 g−1). The carbon aerogels show very promising potential in the separation/extraction of organic pollutants and for energy storage. [ABSTRACT FROM AUTHOR]

Photochemically mediated atom transfer radical polymerization of vinyl monomers is successfully activated by ecofriendly heterogeneous mesoporous graphitic carbon nitride (mpg-C3N4). This method pertains to the use of mpg-C3N4 as photoactivator for reduction of initially loaded copper(II) species, thus promoting the in situ formation of the copper(I) species. The controlled nature of the polymerizations in both natural sunlight and UV-light irradiation at ambient temperature is confirmed by the good agreement of the kinetics of the ­polymerization with theoretical values. The light on-off experiments ­demonstrate that polymerizations are clearly initiated and moderated by either UV light or sunlight. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, polymeric/polymerized ionic liquids or poly(ionic liquid)s (PILs) were found to take an enabling role in some fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the flexibility and properties of macromolecular architectures and provide novel properties and functions that are of huge potential in a multitude of applications, including solid ionic conductor, powerful dispersant and stabilizer, absorbent, precursor for carbon materials, porous polymers, etc. So far, the preparation of PILs with various forms in cations and anions has mostly focused on the conventional free radical polymerization of IL monomers. Recent progress in the preparation of PILs via controlled/“living” radical polymerizations points out an unprecedented opportunity to precisely design and control macromolecular architecture of IL species on a meso-/nanoscale within a polymer matrix. There are also newly emerging polymerization techniques that have appeared for the preparation of PILs which have further pushed the limit of the design of PILs. In this review, we try to summarize the current preparative strategies of PILs, providing a systematic and actual view on the polymer chemistry behind. A discussion of the properties and applications of PILs constitutes the second part of this review. [Copyright &y& Elsevier]

Abstract: One of the recent major improvements of HPLC was the introduction of monolithic silica columns, which have the advantage of faster separation and lower back pressure as compared to common silica beads. Here, we present an interesting alternative to such reversed-phase monolithic columns by a convenient coupling route of a thermo-responsive polymer to hydrophilic silica monoliths. Poly(N-isopropylacrylamide) (PNIPAM) was polymerized in solution via a reversible addition fragmentation chain transfer (RAFT) polymerization technique and coupled then in situ onto an amino-modified silica monolithic column. These columns were compared with RP-18 monolithic columns in the separation of steroids under isocratic condition in aqueous mobile phase. Separation is optimized just by changing the temperature, instead of changing the mobile phase composition. [Copyright &y& Elsevier]

Copolymers of 1,1-diphenylethylene (DPE) behave in a very special way in radical polymerization. Particularly, the behavior of MMA–DPE copolymers in radical polymerization is investigated. The results reveal that the semiquinoid structure of the precursor polymer identified in a previous contribution is activated by the attack of free radicals and thus, in a second stage polymerization with a second monomer, block copolymers are formed. The block copolymer yield depends strongly on the ratio between the amount of DPE-containing precursor polymer and the initiator and monomer concentration used in the second stage. The mechanism proposed is able to explain at least qualitatively all experimental results including the restriction of this mode of control of radical polymerization to the formation of diblock copolymers only. [Copyright &y& Elsevier]

Miniemulsions are specially formulated heterophase systems where stable nanodroplets of one phase are dispersed in a second, continuous phase. It is delineated that miniemulsions rely on the appropriate combination of saturated high shear treatment, surfactants, and the presence of an osmotic pressure agent insoluble in the continuous phase. The droplet diameter is adjusted by the type and amount of surfactant, the volume fraction of disperse phase, and the general dispersion problem and lies between 30 and 500 nm. Since each of those droplets can be regarded as an individual batch reactor, a whole variety of polymerization reactions can be performed starting from miniemulsions, clearly extending the profile of classical emulsion polymerization. This article gives an overview about the mechanisms of formation of and polymerization in miniemulsions and reviews the current standing of the field for both the synthesis of new polymers and disperses hybrid systems from heterophase situations. [Copyright &y& Elsevier]

Fully aromatic polyimides are synthesized via solid-state polymerization of the corresponding monomer salts. The crystal structure of salts shows strong hydrogen bonding of the reactive groups and thereby paves the way for solid-state transformations. The polycondensation yields copies of the initial salt crystallite habits, accompanied by the development of a porosity especially suited for CO2. [ABSTRACT FROM AUTHOR]

Humic Acid is a natural polymer with high functionality which is omnipresent in Nature, but was up to now hardly considered as an object of polymer synthesis. We review the known structural properties of natural humic acids which are remarkably uniform, independent of source and origin and environment. We then present its simple retrosynthesis in the lab based on a hydrothermal polycondensation process. The for a polymer very unusual properties of Humic Acid, such as pH and redox buffering, strong ion binding, but also its ability to bind and carry both hydrophobic and very hydrophilic molecules make artificial humic acid also an exciting choice as a functional polymer for technical purposes. [ABSTRACT FROM AUTHOR]

The polymerization of phenol–formaldehyde resin under hypersaline conditions, for example, in the presence of ZnCl2, generates a black monolith. In their Communication on page 14623 ff., N. Fechler, M. Antonietti, S. H. Yu et al. further show that a foam‐like carbon aerogel with good mechanical robustness can be directly obtained from the monolith without any special drying processes. ZnCl2 plays a key role in this process, serving as dehydration agent, foaming agent, and porogen. [ABSTRACT FROM AUTHOR]

Sugars can be directly …︁ …︁ transformed into porous nitrogen‐doped carbon materials in the presence of poly(ionic liquid)s. In their Communication on page 6028 ff., J. Yuan, Y. Wang, and co‐workers describe the application of this method to synthesize carbon particles 20–50 nm in size and also to synthesize, in one step, nitrogen‐doped carbon materials embedded with core–shell Au–Pd nanoparticles. [ABSTRACT FROM AUTHOR]

The utilization of graphitic carbon nitride (g-CN) as photoinitiator for hydrogel formation is reported. On top of the photochemical activity, g-CN entails the role of a reinforcing agent. Hydrogels formed via g-CN (0.6 wt % g-CN and 11 wt % solid content in total) possess significantly increased mechanical strength, around 32 times stronger storage moduli (from 250 Pa for the reference sample up to 8300 Pa for g-CN derived hydrogels) than the ones initiated with common radical initiators. In addition, the g-CN derived hydrogels show mechanical properties that are pH dependent. Therefore, g-CN acts as a photoinitiator for hydrogel formation and as reinforcer at the same time. [ABSTRACT FROM AUTHOR]

Abstract: This review presents a literature survey of recent work on poly(ionic liquid)s or polymerized ionic liquids (PILs), a class of polyelectrolytes that has attracted rapidly increasing interest over the past few years. The review begins with a short explanation of the interconnection as well as the intrinsic differences between PILs and ionic liquids. Recently reported PIL homopolymers with new chemical structures and synthetic trends are introduced as a complement to the overall PIL synthesis schemes reported previously. In addition, block copolymers and colloidal particles of PILs are described, followed by a discussion of the limitations of PILs due to structural instability under certain conditions and the efforts to understand PIL physics. Examples of recent applications of PILs across a multitude of fields, such as thermoresponsive materials, carbon materials, catalysis, porous polymers, separation and absorption materials, and energy harvesting/generation as well as several biological applications are described in detail. [Copyright &y& Elsevier]

Abstract: Results on aqueous heterophase polymerization in the presence of either 1,1-diphenylethylene or water-soluble precursor polymers containing an α,p-dimer unit of 1,1-diphenylethylene are reported. The precursor polymers are bound covalently to the particles due to a special kind of chain transfer reaction showing on the one hand some features of controlled radical polymerization and leading on the other hand to the formation of block copolymers. Moreover, the covalently bound precursor molecules act as very efficient colloidal stabilizers of the final dispersion and thus, they can be considered as reactive surfactant with the additional ability to control radical polymerization (controlsurf). Under optimum conditions the precursor polymer molecules are almost completely covalently attached to polymer particles. Results are presented regarding block copolymer yields, solids content, and particle diameter in dependence on the polymerization conditions, particularly the precursor polymer concentration, the monomer as well as the initiator concentration, and the initiator type. Under optimum conditions the attainable block copolymer yields and the solids content of the final latexes can be above 95 and about 40%, respectively. Based on experimental results the mechanism of this special kind of controlled radical polymerization under the peculiarities of aqueous heterophase polymerization is discussed. [Copyright &y& Elsevier]

The role of 1,1-diphenylethylene (DPE) in radical emulsion polymerization of methyl methacrylate is investigated. The presence of DPE causes a strong decrease in both the rate of polymerization and the molecular weight. According to the results of structure analysis by means of MALDI-TOF mass spectrometry, UV–vis spectroscopy, and 1H–NMR spectroscopy, DPE is incorporated in the copolymer chain exclusively as a reactive recombinant α,p-dimer, underlining the peculiar role of DPE in radical polymerizations. [Copyright &y& Elsevier]

Herein, an approach via combination of confined porous textures and reversible deactivation radical polymerization techniques is proposed to advance synthetic polymer chemistry, i.e., a connection of metal-organic frameworks (MOFs) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Zn2(benzene-1,4-dicarboxylate)2(1,4-diazabicyclo[2.2.2]octane) [Zn2(bdc)2(dabco)] is utilized as a reaction environment for polymerization of various methacrylate monomers (methyl, ethyl, benzyl, and isobornyl methacrylate) in a confined nanochannel, resulting in polymers with control over dispersity, end functionalities, and tacticity with respect to distinct molecular size. To refine and reconsolidate the compartmentation effect on polymer regularity, initiator-functionalized Zn MOF was synthesized via cocrystallization with an initiator-functionalized ligand, 2-(2-bromo-2-methylpropanamido)-1,4-benzenedicarboxylate (Brbdc), in different ratios (10%, 20%, and 50%). Through the embedded initiator, surface-initiated ARGET ATRP was directly initiated from the walls of the nanochannels. The obtained polymers had a high molecular weight up to 392 000. Moreover, a significant improvement in end-group functionality and stereocontrol was observed, entailing polymers with obvious increments in isotacticity. The results highlight a combination of MOFs and ATRP that is a promising and universal methodology to prepare various polymers with high molecular weight exhibiting well-defined uniformity in chain length and microstructure as well as the preserved chain-end functionality. [ABSTRACT FROM AUTHOR]

A non-ionic surfactant system is synthesized by standard grafting of poly(ethylene oxide) from renewable lignin fragments and used for the emulsion polymerization of styrene. The lignin precursors are formed by hydrogenolysis and utilized as initiator for the oxyanionic polymerization of ethylene oxide leading to amphiphilic polymers, very similar to standard nonionic surfactant synthesis. Subsequently, the formed amphiphilic polymers are employed as stabilizers in the heterophase polymerization of styrene with various initiators. Poly (styrene) latexes with solids contents of up to 21% depending on stabilizer concentration have been obtained. Stabilizer efficiencies and performances were nicely comparable with those of nonylphenol-based, non-ionic industrial performance surfactants. [ABSTRACT FROM AUTHOR]

This paper reports on the highly ordered and tunable inner structure of poly(ionic liquid) nanoparticles, which formed spontaneously by precipitation polymerization from water. Without added stabilizer, these "latexes" are much smaller (20-40 nm in diameter) than usual polymer latexes and exhibit either multilamellar or unilamellar vesicular morphology, depending on the tail length of the quaternizing alkyl chains. The simplicity in the synthesis and composition and the high complexity of the ordered structures that resemble liposomes expand the classical profile of homopolymer self-assembly. In addition, unidirectional superassembly to a nanoworm mesostructure is found at elevated concentrations, indicating that the ionic liquid liposomes are apt to integrate into further hierarchical assembly schemes. [ABSTRACT FROM AUTHOR]

Abstract: In this contribution, we demonstrate the controlled synthesis of double hydrophilic block copolymers comprising a hydrophilic poly(ionic liquid) (PIL) segment via the RAFT/MADIX process. The non-ionic segment is made up from either poly(N-isopropylacrylamide) (PNIPAAm) or poly(N,N-dimethylacrylamide) (PDMA), due to their favorable controllable solubility in water at room temperature. They were employed as macro-chain transfer agents (macro-CTAs) for the RAFT polymerization of four different 1-vinylimidazolium ionic liquid monomers possessing different alkyl substitutes and anions. The block copolymers of PNIPAAm-b-PIL are dual stimuli-responsive copolymers that can respond to the changes in temperature and ionic strength in aqueous solution. This special property facilitated a facile anion exchange of the PIL segment. In addition, one copolymer could successfully be employed as carbon precursor for the preparation of mesoporous graphitic nanostructures in the presence of metal salts. [Copyright &y& Elsevier]

Abstract: High surface area organic materials featuring both micro- and mesopores were synthesized under ionothermal conditions via the formation of polyaryltriazine networks. While the polytrimerization of nitriles in zinc chloride at 400 °C produces microporous polymers, higher reaction temperatures induce the formation of additional spherical mesopores with a narrow dispersity. The nitrogen-rich carbonaceous polymer materials thus obtained present surface areas and porosities up to 3300 m[sup2] g[sup-1] and 2.4 cm[sup3] g[sup-1], respectively. The key point of this synthesis relies on the occurrence of several high temperature polymerization reactions, where irreversible carbonization reactions coupled with the reversible trimerization of nitriles allow the reorganization of the dynamic triazine network. The ZnCl[sub2] molten salt fulfills the requirement of a high temperature solvent, but is also required as catalyst. Thus, this dynamic polymerization system provides not only highly micro- and mesoporous materials, but also allows controlling the pore structure in amorphous organic materials. [ABSTRACT FROM AUTHOR]