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The development of sustainable polymer materials, such as biodegradable aliphatic polyesters and natural polymers, has recently become an important issue because of the environmental impact of plastic waste. In this study, we demonstrate the novel synthesis of self-assembling peptide-grafted polyesters. The graft copolymers were prepared via radical ring-opening copolymerization of 2-methylene-1,3-dioxolane (C5), a five-membered cyclic ketene acetal, and tetraleucine peptide macromonomers (MA-Leu4-Am) with various feed compositions, and their structures were characterized by 1H NMR, SEC, and FT-IR analyses. The ring-opening ratio (Rop) of C5 units was almost constant at 70–85% regardless of the feed compositions. In contrast, the values of the grafting ratio of the peptide chain (Gr) were remarkably higher than the values calculated from the feed composition of C5 and MA-Leu4-Am (Gr,feed), reflecting their monomer reactivities. To characterize the copolymerization behavior in detail, density functional theory (DFT) calculations were performed to elucidate the copolymerization mechanisms. These calculations demonstrated that radicals derived from C5 preferentially react with the peptide macromonomer, which was supported by the calculated reaction rate constants and monomer reactivity ratios. [ABSTRACT FROM AUTHOR]

One possible way to store the excess CO2 present in atmosphere is to use it as a reagent for the synthesis of commodities. In particular, CO2 and epoxides can be copolymerized to produce a large variety of polycarbonates which appear very promising in various application fields. Further, the addition of an appropriate transfer agent in the reaction mixture promotes the formation of telechelic polycarbonates which can be used where specific functional polymers are necessary. In this work, (hydroxyethyl) methacrylate and 2‐hydroxyethyl‐2‐bromoisobutyrate species are exploited as transfer agents in the copolymerization of CO2 and cyclohexene oxide, in the presence of a macrocyclic phenolate dimagnesium catalyst. The effect of the transfer agent concentration on the polycarbonate characteristics is evaluated. Finally, the obtained telechelic polycarbonates are used as macromonomers and macroinitiators in the synthesis of statistical and block copolymers. [ABSTRACT FROM AUTHOR]

Molecular bottlebrush (MBB) has been considered as an important type of unimolecular nanomaterial for widespread applications ranging from energy to biomedicine, due to its typical one‐dimensional molecular conformation with tunable aspect ratio and chemical composition. In the recently decades, the ring‐opening metathesis polymerization (ROMP) combined with the grafting‐through strategy has emerged as a powerful tool for synthesizing MBBs with various architecture, including (multi)block MBBs, core‐shell MBBs, random MBBs and Janus MBBs et al. In this review, the recent advances on the synthesis of MBBs including the rational preparation of NB terminated macromonomers (MMs) and the grafting‐through ROMP are briefly summarized. Moreover, the emerging progress on the grafting‐through ROMP performed in the aqueous media is also highlighted. [ABSTRACT FROM AUTHOR]

An orthogonal agent having both alcohol and acylazide groups was used to construct novel polyurethanes by a simple synthetic process. Ring‐opening polymerization (ROP) of δ‐valerolactone from the orthogonal agent afforded a crystalline polymer having acylazide initiation end, while that of δ‐decanolactone resulted in an amorphous polymer. Since acylazide groups undergo thermally induced Curtius rearrangements to yield isocyanate groups, simple heating of above polymers gave macromonomers having both an isocyanate initiation end and an alcohol termination end, which afforded corresponding polyurethane by self‐polyaddition in a bulk condition without any additives. Meanwhile, kinetic analysis of the Curtius rearrangement revealed that a quantitative conversion was reached within a short reaction time, for example at 110°C for 30 min, or at 100°C for 1 h. Moreover, obtained polyurethane species showed unique self‐immolative type thermal degradation behavior. Considering the above, this orthogonal agent turned out to be useful to construct various polyurethane structures by a facile synthetic process, which would contribute to precise polymer synthesis and sequence defined polymer synthesis. [ABSTRACT FROM AUTHOR]

Thermoresponsive hydrogels were 3D-printed with embedded gold nanorods (GNRs), which enable shape change through photothermal heating. GNRs were functionalized with bovine serum albumin and mixed with a photosensitizer and poly(N-isopropylacrylamide) (PNIPAAm) macromer, forming an ink for 3D printing by direct ink writing. A macromer-based approach was chosen to provide good microstructural homogeneity and optical transparency of the unloaded hydrogel in its swollen state. The ink was printed into an acetylated gelatin hydrogel support matrix to prevent the spreading of the low-viscosity ink and provide mechanical stability during printing and concurrent photocrosslinking. Acetylated gelatin hydrogel was introduced because it allows for melting and removal of the support structure below the transition temperature of the crosslinked PNIPAAm structure. Convective and photothermal heating were compared, which both triggered the phase transition of PNIPAAm and induced reversible shrinkage of the hydrogel–GNR composite for a range of GNR loadings. During reswelling after photothermal heating, some structures formed an internally buckled state, where minor mechanical agitation recovered the unbuckled structure. The BSA-GNRs did not leach out of the structure during multiple cycles of shrinkage and reswelling. This work demonstrates the promise of 3D-printed, photoresponsive structures as hydrogel actuators. [ABSTRACT FROM AUTHOR]

Polymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate‐2‐(4‐ethenylphenyl)‐5,5‐dimethyl‐1,3,2‐dioxaborinane) P(HMA‐co‐ViCL) copolymers. The ABn ${{AB}_{n}}$ ‐type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high‐performance HBV damping materials. We found that P(HMA‐co‐ViCL) 20k‐40‐60 HBV exhibited ultrahigh energy‐dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials. [ABSTRACT FROM AUTHOR]

Three kinds of slump-retention polycarboxylate superplasticizers(52HPC4, 52IPC4, and 52EPC4) were synthesized by using HPEG, IPEG, or EPEG as macromonomers. The effects of polycarboxylate superplasticizers on the slump-retention of cement and concrete were investigated. The mechanism of action was explained by the composition of PCE polymers and monomer sequences (EHE, HHE, or HHH), which were investigated by using conductivity, GPC, 1H-NMR, and 13C-NMR. The results indicated that the slump flow of cement paste mixed with 52EPC4 was increased quickly within 120 min, while 52IPC4 doesn't change within 240 min. Concrete mixed with 52IPC4 had the best slump-retention performance reaching 440 mm after 150 min, but concrete mixed with 52HPC4 was almost no fluidity after 120 min which had the largest slump flow loss through time than that containing other PCEs, and the conductivity of 52IPC4 aqueous solution decreased more slowly than other PCEs. Because of the highest content of effective PCE polymers, and the largest steric hindrance to ester bond resulting in the concrete had the best slump-retention performance when mixed with 52IPC4, because of the smallest steric hindrance to ester bond resulting in the fastest increase spread flow of cement paste which mixed 52EPC4, because of the highest content of low molecular polymers and the lowest content of effective PCE polymers in 52HPC4 resulting in the smallest initial slump flow of concrete, and the largest slump flow loss through time of concrete, even though the steric hindrance effect was larger than 52EPC4. [ABSTRACT FROM AUTHOR]

The advent of novel polyether macromonomer has garnered significant attention within the industrial domain. In this study, a range of polycarboxylate superplasticizers (PCEs) was produced via free radical polymerization, employing a new polyether monomer, 4‐hydroxybutyl vinyl polyethylene glycol ether (VPEG). This monomer served as the predominant component and was grafted with various functional monomers on its main chain. The molecular configuration of the resultant PCEs was discerned through Fourier infrared spectroscopy and gel permeation chromatography, while the surface tension underwent assessment via a surface tension meter. Both the initial and subsequent fluidity of cement paste and mortar were leveraged to ascertain the dispersion and retention efficacy of the synthetic PCEs. The ramifications of diverse functional group grafts of the new polyether monomer on the cement hydration procedure and strength attributes were elucidated via setting time, hydration heat assays of cement paste, SEM analysis, and compressive strength evaluations of mortar. Observations reveal that the carboxylic acid group significantly reduces surface tension, whereas the sulfonic acid group's effect remains minimal. The incorporation of both the amide and sulfonic acid groups marginally impacts the preliminary dispersion efficacy of PCEs but notably affects dispersion retention. Furthermore, these functional groups facilitate cement hydration, expedite the primary setting time of the cement paste, and bolster the initial compressive strength of the mortar. Specifically, the grafted of sodium methacrylsulfonate (SMAS) yields the most noticeable results. Finally, the working mechanism of PCEs with varying molecular structures has been explained in light both theoretical and experimental results. This research offers valuable insights for subsequent investigations into the fabrication of polycarboxylate superplasticizers using the VPEG macromonomer. [ABSTRACT FROM AUTHOR]

Polymer–protein bioconjugation offers a powerful strategy to alter the physical properties of proteins, and various synthetic polymer compositions and architectures have been investigated for this purpose. Nevertheless, conjugation of molecular bottlebrush polymers (BPs) to proteins remains an unsolved challenge due to the large size of BPs and a general lack of methods to transform the chain ends of BPs into functional groups suitable for bioconjugation. Here, we present a strategy to address this challenge in the context of BPs prepared by "graft-through" ring-opening metathesis polymerization (ROMP), one of the most powerful methods for BP synthesis. Quenching ROMP of PEGylated norbornene macromonomers with an activated enyne terminator facilitates the transformation of the BP Ru alkylidene chain ends into Pd oxidative addition complexes (OACs) for facile bioconjugation. This strategy is shown to be effective for the synthesis of two BP–protein conjugates (albumin and ERG), setting the stage for a new class of BP–protein conjugates for future therapeutic and imaging applications. [ABSTRACT FROM AUTHOR]

Low‐density polyethylene (LDPE) is one of the most important plastics, which is produced unfortunately under extreme conditions. In addition, it consists of robust aliphatic C─C bonds which are challenging to cleave for plastic recycling. A low‐pressure and ‐temperature (pethylene = 2 bara, T = 70 °C) macromonomer‐based synthesis of long chain branched polyethylene is reported. The introduction of recycle points permits the polymerization (grafting to) of the macromonomers to form the long chain branched polyethylene and its depolymerization (branch cleavage). Coordinative chain transfer polymerization employing ethylene and co‐monomers is used for the synthesis of the macromonomers, permitting a high flexibility of their precise structure and efficient synthesis. The long chain branched polyethylene material matches key properties of low‐density polyethylene. [ABSTRACT FROM AUTHOR]

A high‐temperature starved‐feed semi‐batch operating policy is developed to produce p(acrylates) with high macromonomer content, taking advantage of side reactions inherent to acrylate radical polymerization. This operating strategy results in significantly higher macromonomer content for the polymerization of isobornyl acrylate (iBoA) versus n‐butyl acrylate (BA) under identical operating conditions. This is because steric hindrance favors fragmentation (i.e., terminal double bond (TDB) formation) over addition (i.e., short‐chain or long‐chain branch (LCB) formation), thus increasing the p(iBoA) TDB content and decreasing polymer dispersity. The p(iBoA) macromonomer solution serves as an excellent addition‐fragmentation agent to polymerize a second monomer in a single pot process controlled by sequential feeding, as demonstrates by the production of iBoA‐BA block and comb copolymer structures at different temperatures and macromonomer concentrations. The incorporation of the p(iBoA) macromonomer into a copolymer product is verified by various techniques, including polymer fractionation followed by TDB, composition, and molar mass analyses. Reaction temperature plays a key role in determining whether a blocky versus comb copolymer structure is produced. The ability to synthesize block and comb copolymers by radical polymerization without a mediating agent offers the potential to efficiently produce structured copolymers for industrial applications. [ABSTRACT FROM AUTHOR]

Herein, a series of ternary amphiphilic amide-containing bottlebrushes were synthesized by photoiniferter (PI-RAFT) polymerization of macromonomers in continuous-flow mode using trithiocarbonate as a chain transfer agent. Visible light-mediated polymerization of macromonomers under mild conditions enabled the preparation of thermoresponsive copolymers with low dispersity and high yields in a very short time, which is not typical for the classical reversible addition–fragmentation chain transfer process. Methoxy oligo(ethylene glycol) methacrylate and alkoxy(C12–C14) oligo(ethylene glycol) methacrylate were used as the basic monomers providing amphiphilic and thermoresponsive properties. The study investigated how modifying comonomers, acrylamide (AAm), methacrylamide (MAAm), and N-methylacrylamide (-MeAAm) affect the features of bottlebrush micelle formation, their critical micelle concentration, and loading capacity for pyrene, a hydrophobic drug model. The results showed that the process is scalable and can produce tens of grams of pure copolymer per day. The unmodified copolymer formed unimolecular micelles at temperatures below the LCST in aqueous solutions, as revealed by DLS and SLS data. The incorporation of AAm, MAAm, and N-MeAAm units resulted in an increase in micelle aggregation numbers. The resulting bottlebrushes formed uni- or bimolecular micelles at extremely low concentrations. These micelles possess a high capacity for loading pyrene, making them a promising choice for targeted drug delivery. [ABSTRACT FROM AUTHOR]

Reducing the water‐to‐cement (w/c) ratio was the most direct way to decrease the dosage of cement while ensuring compressive strength of concrete. However, the concrete system tend to be more stickiness at low w/c ratio. Four types of polycarboxylate superplasticizers (PCEs) were synthesized using HPEG, IPEG, EPEG, or VPEG as macromonomers. The impact of PCEs on the viscosity and workability of cement and concrete was investigated. The mechanism behind the macroscopic properties exhibited by these four PCEs was explored through surface tension analysis, GPC analysis, NMR analysis, and adsorption capacity evaluation. The results indicated that, at high w/c ratio (≥0.35), concrete mixed with four types of PCEs demonstrated almost the same flow velocity and viscosity, at low w/c ratio (≤0.3), the V‐funnel time of concrete which mixed with 67EPC3.5 reached 8.5 s, showed the fastest flow velocity and lowest viscosity, due to the structure of 67EPC3.5 containing the highest content of combined units of AAA which resulted in rapid adsorption rate and maximum adsorption quantity, and the viscosity effect was independent of surface tension. Concrete mixed with 67IPC3.5 displayed the superior workability at any w/c ratio primarily because the structure of 67IPC3.5 contained the highest content of polyoxyethylene ether which effectively reduced surface tension. [ABSTRACT FROM AUTHOR]

Reconstructing functional sequence motifs of proteins, using statistical copolymers greatly reduces the information content, but simplifies synthesis significantly. Key amino acid residues involved in the adhesion of mussel foot proteins are identified. The side‐chain functionalities of Dopa, lysine, and arginine are abstracted and incorporated into acrylate monomers to allow controlled radical polymerization. The resulting Dopa‐acrylate (Y*‐acr), arginine‐acrylate (R‐acr), and lysine‐acrylate (K‐acr) monomers are polymerized in different monomer ratios and compositions by reversible addition fragmentation transfer polymerization with a poly(ethylene glycol) (PEG) macrochain transfer agent. This results in two sets of PEG‐block‐copolymers with statistical mixtures and different monomer ratios of catechol/primary amine and catechol/guanidine side‐chain functionalities, both important pairs for mimicking π‐cation interactions. The coating behavior of these PEG‐block‐copolymers is evaluated using quartz crystal microbalance with dissipation energy monitoring (QCM‐D), leading to non‐covalent PEGylation of the substrates with clear compositional optima in the coating stability and antifouling properties. The coatings prevent non‐reversible albumin or serum adsorption, as well as reduce cellular adhesion and fungal spore attachment. [ABSTRACT FROM AUTHOR]

The development of poly(ethylene oxide) (PEO)‐based solid polymer electrolytes (SPEs) is limited by the semi‐crystalline nature of PEO and the extremely strong EO‐Li+ interactions. To promote the rapid migration of Li+, a one‐step method combining radical polymerization and ring‐opening polymerization catalyzed simultaneously by lithium carboxylate is proposed to construct multi‐component graft copolymer electrolytes (GCPEs) in this study. Tailored macroinitiator with catalytic and initiated sites (PAALi(OH‐Br)) realizes one‐step polymerizations of vinyl monomers and cyclic monomers, and provides GCPEs with poly(ethylene glycol) (PEG) and poly(ε‐caprolactone) (PCL) side chains. The grafted structure of GCPE greatly facilitates the intra‐chain hopping of Li+, resulting in excellent ionic conductivity. The introduction of PCL further improves the tLi+ of GCPE. The three‐component graft copolymer electrolyte constructed by polystyrene (PS), PEO, and PCL exhibits high tensile stress (1.62 MPa), a high ionic conductivity (2.4 × 10−5 S cm−1, 30 °C), and a high tLi+ of 0.47 and high electrochemical stability. [ABSTRACT FROM AUTHOR]

The integration of liposomes into hydrogels through direct soaking presents advantages such as facile formulation, enhanced drug stability, and controlled release kinetics. However, the feasibility of this approach is impeded by the difficulty of developing matching porous structures within hydrogels and achieving appropriate affinity with liposomes. To address these challenges, an alternative method is proposed for synthesizing macroporous hydrogels using thiolated hyaluronic acid and hyperbranched polyethylene glycol macromonomers in combination with a freezing‐induced secondary crosslinking process. This approach allows the locking of macropores formed by ice crystals during freezing and enables easy modification of the hydrogels with cholesterol groups to promote liposome association. Furthermore, these macroporous hydrogels can be crushed into granular hydrogels, which offer numerous benefits such as high loading capacity, injectability, self‐healing properties, and convenience in storage, dosing, and administration. Therefore, a liposome‐in‐hydrogel system can be formulated without any gelation or pre‐treatment, providing valuable insights for the further development of liposome‐based formulations for medical and cosmetic applications. [ABSTRACT FROM AUTHOR]

During the two last decades, covalent adaptable networks (CANs) have proven to be an important new class of polymer materials combining the main advantages of thermoplastics and thermosets. For instance, materials can undergo reprocessing cycles by incorporating dynamic covalent bonds within a cross‐linked network. Due to their versatility, renewable resources can be easily integrated into these innovative systems to develop sustainable materials, which can be related to the context of the recent development of a circular bioeconomy. Lignins, the main renewable sources of aromatic structures, are major candidates in the design of novel and biobased stimuli‐responsive materials such as vitrimers due to their high functionality and specific chemical architectures. In the aim of developing recyclable lignin‐based vinylogous urethane (VU) networks, an innovative strategy was elaborated in which lignin was first modified into liquid polyols and then into polyacetoacetates. Resulting macromonomers were integrated into aromatic VU networks and fully characterized through thermal, mechanical, and rheological experiments. Viscoelastic behaviors of the different aromatic vitrimers exhibited fast stress‐relaxations (e. g., 39 s at 130 °C) allowing easy and fast mechanical reprocessing. A thermomechanical recycling study was successfully performed. Then, the developed strategy enabled the fabrication of healable biobased aromatic vitrimers with tunable structures and properties. [ABSTRACT FROM AUTHOR]

The presented work deals with the photocuring of telechelic macromonomers derived from plant-based fatty acids to obtain a soft polymer network. Compositions were made by mixing macromonomers with three different concentrations (0.5, 1, and 2%) of two type I photoinitiators (Omnirad 2022 and Omnirad 819). All formulations were then subjected to photopolymerization studies by applying UV-assisted differential scanning calorimetry (UV-DSC) measurements at isothermal conditions at 37 °C with a narrow light source wavelength of 365 nm and irradiation (light intensity) of 20 and 50 mW/cm2. The percentage conversions, reaction orders, and constants were estimated based on autocatalytic Sestak–Berggen and Avrami models. In this work, for the first time, the influence of the curing conditions on the photopolymerization process, such as the photoinitiator concentration, light intensity, and oxygen presence/absence, were investigated for these novel systems. The results indicated significant differences between the two commercially available photoinitiators and their effects on photopolymerization kinetics. The maximum reaction rate was found to be considerably higher for Omnirad 2022 (which is a blend of three different compounds), especially at a lower light intensity, i.e., 20 mW/cm2, compared to Omnirad 819. However, it led to lower maximum conversion in an air atmosphere. The dynamic thermomechanical analysis (DMTA) revealed that light intensity, photoinitiator concentration, and oxygen presence had a strong effect on the storage modulus and loss modulus values. It was concluded that the chemical structure of the photoinitiator and curing conditions had a strong effect on the photopolymerization kinetics and properties of the prepared soft polymer networks. [ABSTRACT FROM AUTHOR]

Cyclic polymers have very unique structure and properties, and thus have drawn intense research attention. However, controlled synthesis of cyclic polymers with predictable molar mass and narrow distribution is still a challenging task. In this study, we developed a novel cyclic catalyst that initiates the ring-expansion polymerisation of isocyanides, producing a series of cyclic helical polymers with predictable molecular weight and low dispersity. Interestingly, the ring-expansion polymerization of the isocyanide macromonomers gives well-defined cyclic bottlebrush polymers. The cyclic topology was demonstrated using transmission electron microscopy. [ABSTRACT FROM AUTHOR]

In this work, a series of monomethoxy poly(ethylene glycol)‐polycaprolactone (mPEG‐PCL) copolymers with different mass percentages of mPEG was chemically synthesized as form‐stable phase change materials (FSPCMs) for thermal energy storage (TES) application for the first time. Their chemical structures, surface morphology, and thermal properties were studied in terms of nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). 1H NMR, gel permeation chromatography (GPC), and FTIR results confirmed the successful ring‐opening polymerization of ϵ‐caprolactone with mPEG macromonomer, and the respective average molecular weight of the copolymers was obtained in the range of 9704–17346 g mol−1. DSC analysis results revealed that the copolymers have a phase change temperature and latent heat in the range of 52.8–57.9 °C and 88.8–114.4 J g−1 respectively and TGA analysis showed that they are thermally stable up to 150 °C. Leakage test results showed that the copolymers (mPEG)x‐(PCL)y displayed excellent form stability with minimal leakage while thermal cycling revealed good thermal reliability. In addition, the copolymers successfully demonstrated their ability to store and release heat for a prolonged period, making them suitable for TES applications like heating water storage tanks. [ABSTRACT FROM AUTHOR]

Cell-releasing hydrogel carriers enhance cell-based therapies by improving retention and viability within target tissues. We previously demonstrated tunable cell release from a hydrolytically labile β-thioester-containing polyethylene glycol-based hydrogel. However, the macromer synthesis dependent on thiol-Michael addition leads to batch variability and heterogeneous hydrogel properties. Herein, we report a new synthetic route with improved control of macromer molecular weight and characterize the resulting hydrogel properties. The resulting PEG dithioester acrylamide (PEGDTEA) hydrogel demonstrates a more controlled synthetic route to generate targeted molecular weights with reduced couplings, creating a more predictable and tunable hydrogel microenvironment for precise cell delivery applications. [ABSTRACT FROM AUTHOR]

Some possibilities to obtain functional materials based on poly[(Nacylimino) ethylene] (PROZO) macromonomers, such as functional latexes, graft copolymers and gels or interpenetrated polymer networks are discussed. The influence of the macromer structure in the preparation of polymer microparticles with narrow size distribution by different heterogeneous polymerization techniques (soapless emulsion polymerization, dispersion polymerization) was comparatively studied. The experimental data point on the possibility to control the characteristics of the produced materials-envisaging mainly biomedical applications. [ABSTRACT FROM AUTHOR]

Highly efficient one-pot synthesis of hexakis(m-phenyleneimine) macrocycle Cm6 from acetalprotected AB-type monomer, m-aminobenzaldehyde diethylacetal, was successfully achieved based on imine dynamic covalent chemistry and precipitation-driven cyclization. The structure of Cm6 in the solid state was determined using CP/MAS NMR, X-ray single crystallographic analysis, and WAXD. Macrocycle Cm6 is composed of six phenylene and imine bonds facing the same direction, with nitrogen atoms arranged on the outside of the ring, and has a chair conformation, as predicted from DFT calculation. The macrocycle forms π-stacked columnar aggregates and hexagonally closest-packed structure. The cyclization process was investigated using MALDI-TOF MS and NMR. A mechanism of precipitation-driven cyclization based on imine dynamic covalent chemistry and π-stacked columnar aggregation is proposed. Both the nature of imine linkage and the shape anisotropy of the macrocycle played an important role in the single one-pot synthesis. The water-mediated mutual conversion between macrocycle Cm6 and linear oligomers driven by thermal stimulation was analyzed using MALDI-TOF MS and GPC methods. Macrocycle Cm6 with a dynamic covalent imine bond exhibited self-healing properties when stimulated using heat. [ABSTRACT FROM AUTHOR]

Engineered polylactic acid (PLA) nanoparticles synthesized from oligo(lactic acid) macromonomers have been studied over the last decades for controlled drug delivery. These macromonomers are typically produced via ring‐opening polymerization (ROP) of the cyclic dimer lactide, initiated by 2‐hydroxyethyl methacrylate (HEMA). This reaction route, despite leading to well‐defined macromonomers, relies on the production of lactide from lactic acid, which burdens the ROP overall cost for more than 30%. In this work, we report the synthesis of PLA‐based macromonomers by direct polycondensation of lactic acid in the presence of HEMA as a valuable alternative to ROP. In particular, we compare the two processes side by side, focusing on the production of three HEMA‐LAn macromonomers, with n = 2, 4, and 6. Detailed kinetic models are developed for both reaction systems, and the corresponding parameters are estimated by fitting the experimental data. Through these models, the reaction kinetics as well as the time evolution of the entire chain length distributions of the products from polycondensation and ROP could be reliably predicted. This way, we demonstrated that polycondensation is a valuable alternative to ROP only for macromonomers with an average chain length of up to 4 and that ROP remains the main route to longer chains, when a strict control over the chain length distribution is required. [ABSTRACT FROM AUTHOR]

Aiming at the creation of polymers with attractive dynamic properties, herein, rotaxane-branched dendronized polymers (DPs) with rotaxane-branched dendrons attached onto the polymer chains are proposed. Starting from macromonomers with both rotaxane-branched dendrons and polymerization site, targeted rotaxane-branched DPs are successfully synthesized through ring-opening metathesis polymerization (ROMP). Interestingly, due to the existence of multiple switchable [2]rotaxane branches within the attached dendrons, anion-induced reversible thickness modulation of the resultant rotaxane-branched DPs is achieved, which further lead to tunable thermal and rheological properties, making them attractive platform for the construction of smart polymeric materials. Enriching the toolbox of polymers, the design and construction of novel polymers with desired properties and functions remains an attractive topic in polymer chemistry. Here the authors demonstrate rotaxane-branched dendronized polymers with rotaxane-branched dendrons attached onto the polymer chains as polymers with attractive dynamic properties. [ABSTRACT FROM AUTHOR]

Macromolecules obtained from renewable natural sources are gaining increasing attention as components for a vast variety of sustainable polymer-based materials. Natural raw materials can facilitate continuous-flow production due to their year-round availability and short replenishment period. They also open new opportunities for chemists and biologists to design and create "bioreplacement" and "bioadvantaged" polymers, where complex structures produced by nature are being modified, upgraded, and utilized to create novel materials. Bio-based macromonomers are expected not only to compete with but to replace some petroleum-based analogs, as well. The development of novel sustainable materials is an ongoing and very dynamic process. There are multiple strategies for transforming natural macromolecules into sophisticated value-added products. Some methods include chemical modification of macromolecules, while others include blending several components into one new system. One of the most promising approaches for incorporating renewable macromolecules into new products is the synthesis of hybrid networks based on one or more natural components. Each one has unique characteristics, so its incorporation into a network brings new sustainable materials with properties that can be tuned according to their end-use. This article reviews the current state-of-the-art and future potential of renewable natural macromolecules as sustainable building blocks for the synthesis and use of hybrid polymer networks. The most recent advancements and applications that involve polymers, such as cellulose, chitin, alginic acid, gellan gum, lignin, and their derivatives, are discussed. [ABSTRACT FROM AUTHOR]

The application of N‐heterocyclic carbene (NHC) catalysis under highly diluted oxidative condition to the polycondensation of dialdehydes and diols is herein presented as an alternative, atom‐economical synthetic route to macrocyclic oligoesters (MCOs). The disclosed protocol paves the way to the straightforward access to MCOs, starting from commercial dialdehydes, avoiding the use of toxic diacyl chlorides, commonly employed in traditional MCOs synthetic processes. The method is totally metal‐free, takes place in the green Me‐THF solvent and requires the use of a fully recyclable quinone oxidant. The protocol versatility is confirmed by the employment of fossil‐based and bio‐based monomers such as 2,5‐diformylfuran (DFF), 2,5‐bis(hydroxymethyl)furan (BHMF), and isomannide, synthesizing a series of novel and known synthetically relevant macrocyclic oligoesters, fully characterized by NMR and MALDI‐TOF MS analysis, with product yields (51–86 %) comparable to those obtained by traditional synthetic routes. Finally, to emphasize the synthetic relevance of the target macrocycles, an entropically‐driven ring opening polymerization (ED‐ROP) key study has been performed, optimizing the organocatalyzed synthesis of poly(2,5‐furan‐dimethylene 2,5 furandicarboxylate) (PBHMF) with number‐average molecular weight up to 8200 g mol−1 and 66 % isolated yield. [ABSTRACT FROM AUTHOR]

Methacrylic acid‐co‐poly(ethylene glycol methacrylate) (MAA‐co‐PEGMA) copolymers (MPEG‐type polycarboxylate ether (PCE) superplasticizers) are characterized by a comb‐like structure. Although they have been used for years as dispersants in cementitious formulations, their structure–property relationship is still not fully understood. In this work, PCEs with uniform composition and different charge‐density (N) or different side chain lengths (P) are synthesized by free‐radical copolymerization varying the MAA/PEGMA ratios and ethylene oxide units in the PEGMA macromonomers. The effect of these copolymers on the hydration kinetics of an Ordinary Portland Cement (OPC) is analyzed, and it is observed that by increasing the PCE concentration the hydration is delayed. For a given PCE concentration, the delay is longer as the MAA/PEGMA ratio increases or the side chain length of the PEGMA decreases. The hydration delay is proportional to the carboxylate dosage and all PCEs fit in a master curve proving that the microstructure of the PCEs synthesized by free‐radical copolymerization can be correlated with the hydration delay of a commercial OPC. [ABSTRACT FROM AUTHOR]

Polyolefins with periodic unsaturation in the backbone chain are sought after for synthesizing chemically recyclable polymers or telechelic polyolefin macromonomers. Here we introduce a bottom‐up synthesis of unsaturated high‐density polyethylene (HDPE) via copolymerization of ethylene with dimethyl 7‐oxabicyclo[2.2.1]hepta‐2,5‐diene‐3,5‐dicarboxylate followed by post‐polymerization retro‐Diels–Alder to unveil hidden double bonds in the polymer backbone. The incorporation of this "Trojan Horse" comonomer was varied and a series of unsaturated HDPE polymers with block lengths of 1.2, 1.9, and 3.5 kDa between double bonds was synthesized. Cross metathesis of unsaturated HDPE samples with 2‐hydroxyethyl acrylate yielded telechelic ester terminated PE macromonomers suitable for the preparation of ester‐linked PE. These materials were depolymerized and repolymerized, making them suitable candidates for chemical recycling. The ester‐linked PE displayed thermal and mechanical properties comparable to commercial HDPE. [ABSTRACT FROM AUTHOR]

Graft copolymer can be synthesized by the copolymerization of macromonomer and co-monomer. However, the synthesis of vinyl-terminal macromonomer with hybrid backbone by a simple route was rather difficult. Here, N-hydroxyethyl acrylamide(HEAA)was employed as a monomer to prepare vinyl-terminal macromonomer through oxa-Michael polyaddition. The resulted macromonomer composed from amide and ether groups in the backbone was then copolymerized with methyl methacrylate(MMA)forming a graft copolymer. The structures and properties of macromonomers and corresponding graft copolymers were analyzed by nuclear magnetic resonance spectroscopy(NMR), gel permeation chromatography(GPC)and differential scanning calorimetry(DSC). The results showed that poly(amide-co-ether)macromonomers could be successfully prepared by the oxa-Michael polyaddition of HEAA. The conversion of HEAA was close to 100%. No vinyl addition reaction was observed during the polymerization. The molecular weight of the synthesized graft copolymer was 26 700 g/mol with a polydispersity index of 1.58 and the glass transition temptation of 66.3 ℃. [ABSTRACT FROM AUTHOR]

In this article, the biocatalytic oxidation of ethanol into acetaldehyde was studied using a catalase entrapped within a monolithic polyampholyte cryogel, p(APTAC-co-AMPS), as catalyst. When an anionic monomer, 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPS), was mixed with a cationic monomer, (3-acrylamidopropyl) trimethylammonium chloride (APTAC), under cryo-polymerization conditions at a molar ratio of monomers [APTAC]:[AMPS] = 75:25 mol.% in the presence of 10 mol.% cross-linking agent, N,N-methylenebisacrylamide (MBAA), the macroporous polyampholyte cryogels containing various amounts of catalase were synthesized in situ. The conversion of ethanol into acetaldehyde in good-to-high yields was observed in flow-through and batch-type reactors under optimal conditions: at T = 10–20 °C, pH = 6.9–7.1, [C2H5OH]:[H2O2] = 50:50 vol.%. According to the SEM images, the pore sizes of the p(AMPS-co-APTAC) cryogel vary from 15 to 55 μm. The catalytic activity of catalase entrapped within a monolithic polyampholyte cryogel in the conversion of ethanol into acetaldehyde was evaluated through the determination of kinetic parameters such as the Michaelis constant (Km), maximum enzymatic rate (Vmax), activation energy (Ea), turnover number (TON) and turnover frequency (TOF). The catalase encapsulated within the monolithic polyampholyte cryogel exhibits a high conversion of ethanol into acetaldehyde. The key parameters of ethanol oxidation in flow and batch reactors in the presence of the cryogel monolith were calculated. [ABSTRACT FROM AUTHOR]

In this research, functionalization of the easily available polyalphaolefin (PAO) based resins is accomplished by the copolymerization of 1-decene with 9-decenol through a facile cationic polymerization route. The resultant co-oligomer was further functionalized with acryloyl chloride to synthesize a macromer product. The exact microstructure of synthesized and modified resins was explored via H-NMR, FTIR and GPC analytical methods. The PAO chains contain roughly 20 monomeric units in which three polymerizable C = C moieties could be embedded. The crosslinking of macromer started by visible light irradiation provided final fabricate. The effect of photo-initiator content on the cross-linking kinetics of the resin was explored using shrinkage strain measurement. The resulting three-dimensional PAO (3D-PO) revealed hydrophilic nature with water contact angle of 65° and excellent cell viability of 93% in the MTT assay. This strategy starts from easily available α-olefin based monomers, employs a facile cationic polymerization procedure, enables modulation of the functional groups in the macromer backbone in order to make it photo-polymerizable, and holds great potential for tissue engineering applications. [ABSTRACT FROM AUTHOR]

Pollution with organic dyes is one of the most typical environmental problems related to industrial wastewater. The removal of these dyes opens up new prospects for environmental remediation, but the design of sustainable and inexpensive systems for water purification is a fundamental challenge. This paper reports the synthesis of novel fortified hydrogels that can bind and remove organic dyes from aqueous solutions. These hydrophilic conetworks consist of chemically modified poly(ethylene glycol) (PEG-m) and multifunctional cellulose macromonomers ("cellu-mers"). Williamson etherification with 4-vinylbenzyl chloride (4-VBC) is used to modify PEGs of different molecular masses (1, 5, 6, and 10 kDa) and cellobiose, Sigmacell, or Technocell™ T-90 cellulose (products derived from natural renewable resources) with polymerizable/crosslinkable moieties. The networks are formed with good (75%) to excellent (96%) yields. They show good swelling and have good mechanical properties according to rheological tests. Scanning electron microscopy (SEM) reveals that cellulose fibers are visibly embedded into the inner hydrogel structure. The ability to bind and remove organic dyes, such as bromophenol blue (BPB), methylene blue (MB), and crystal violet (CV), from aqueous solutions hints at the potential of the new cellulosic hydrogels for environmental cleanup and clean water safeguarding. [ABSTRACT FROM AUTHOR]

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The effects of 1 % xanthan gum (XG) and hydroxypropyl methylcellulose (HPMC) on the physicochemical and structural properties of triticale gluten (TG) during fermentation were investigated. Rheological analysis revealed that the addition of XG or HPMC decreased G′ and G″ values, while increasing tanδ and recovery strain of triticale gluten during fermentation. Thermal gravimetric analysis demonstrated that triticale gluten added with XG after fermentation exhibited the highest residual mass, showing a 9.3 % increase compared to TG. Microscopic observations indicated that the addition of XG or HPMC during fermentation resulted in a more continuous and compact network structure of triticale gluten. Analysis of secondary structure, disulfide bond formation, and macromer content revealed that 1 % XG significantly enhanced the formation of interchain disulfide bonds (1.9 μmol/g), elevated the β-folding ratio (43.58 %), and increased the gluten-macromer content (2.2 %) during fermentation. Surface hydrophobicity and electrophoresis analyses suggested that the interaction between hydrocolloids and gluten enhanced the exposure of hydrophobic groups of gluten. This study offers insights into the potential applications of XG and HPMC in fermented triticale products. • Xanthan gum (XG) increases the ratio of disulfide bonds in gluten. • XG makes the network structure formed by gluten molecules more continuous. • Hydroxypropyl methylcellulose (HPMC) and XG increase the thermal stability of gluten. • HPMC and XG increase the exposure of hydrophobic groups in gluten molecules. [ABSTRACT FROM AUTHOR]

This work establishes the design of a fully synthetic, shear-thinning hydrogel platform that is injectable and can isolate engineered, allogeneic cell therapies from the host. We utilized RAFT to generate a library of linear random copolymers of N,N-dimethylacrylamide (DMA) and 2-vinyl-4,4-dimethyl azlactone (VDMA) with variable mol% VDMA and degree of polymerization. Poly(DMA- co -VDMA) copolymers were subsequently modified with either adamantane (Ad) or β-cyclodextrin (Cd) through amine-reactive VDMA to prepare hydrogel precursor macromers containing complementary guest-host pairing pendant groups that, when mixed, form shear-thinning hydrogels. Rheometric evaluation of the hydrogel library enabled identification of lead macromer structures comprising 15 mol% pendants (Ad or Cd) and a degree of polymerization of 1000; mixing of these Ad and Cd functionalized precursors yielded hydrogels possessing storage modulus above 1000 Pa, tan(δ) values below 1 and high yield strain, which are target characteristics of robust but injectable shear-thinning gels. This modular system proved amenable to nanoparticle integration with surface-modified nanoparticles displaying Ad. The addition of the Ad-functionalized nanoparticles simultaneously improved mechanical properties of the hydrogels and enabled extended hydrogel retention of a model small molecule in vivo. In studies benchmarking against alginate, a material traditionally used for cell encapsulation, the lead hydrogel showed significantly less fibrous encapsulation in a subcutaneous implant site. Finally, this platform was utilized to encapsulate and extend in vivo longevity of inducible transgene-engineered mesenchymal stem cells in an allogeneic transplant model. The hydrogels remained intact and blocked infiltration by host cells, consequently extending the longevity of grafted cell function relative to a benchmark, shear-thinning hyaluronic acid-based gel. In sum, the new synthetic, shear-thinning hydrogel system presented here shows potential for further development as an injectable platform for delivery and in situ drug modulation of allograft and engineered cell therapies. [Display omitted] [ABSTRACT FROM AUTHOR]

PolyHIPEs are macroporous polymers templated within high internal phase emulsions (HIPEs). The ability to tailor the macromolecular and porous structures makes polyHIPEs of interest for three dimensional tissue engineering scaffolds. In this work, polyHIPEs with densities ranging from 0.18 to 0.28 g/cc were synthesized from novel biodegradable poly(ɛ-caprolactone) (PCL) macromers based on methacrylated oligomeric PCL diols of various molecular weights. Different types of internal phases generated porous structures that varied from networks of channels to highly interconnected voids. The crosslinked macromolecular structure limited PCL crystallization, resulting in elastomeric behavior with moduli of around 20 kPa. The HIPEs proved suitable for 3D printing both in air and in an innovative gel-bath. The suitability of the polyHIPEs for tissue engineering applications was indicated by their moduli, by their complete degradation within 4 h in 3 M NaOH, and by mesenchymal stem cells adhering and proliferating. The high level of viability can be attributed to the porosity that enables sufficient nutrient and waste diffusion. These results provide a foundation for designing 3D HIPE inks for printing macroporous tissue engineering scaffolds. [Display omitted] • Porous polycaprolactone (PCL): high internal phase emulsion (HIPE) templating. • Methacrylated PCL oligomers, various molecular weights (MWs): Elastomeric monoliths. • Porous structure affected by internal phase, crosslinked structure by MW. • 3D photo-printing: polymerize between layers in air, after printing in a gel-bath. • Mesenchymal stem cells adhered, proliferated. Porosity: nutrient, waste diffusion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polymerization kinetics of linear and branched Poly(HEA) via RDRP in aqueous solution were investigated. • Linear and branched Poly(HEA) coatings were prepared by SI-RDRP to membrane surfaces. • Branched Poly(HEA) brush coating showed more excellent antifouling performance. Fabrication of hydrophilic coatings on membrane surface is one of the best methods to solve membrane fouling caused by oil or other pollutants. Recently, branched macromonomer as cross-linker in polymerization are proved to favor the uniformity and stability of coatings. Herein, we synthesized a branched macromonomer poly(ethylene glycol dimethacrylate) (BP(EGDMA)), which had abundant vinyl groups via catalytic chain transfer polymerization (CCTP), for fabrication of zwitterionic hydrophilic coatings with low volume shrinkage on different surface through photopolymerization. The low molecular weight cross-linkers with different functionality were used as control groups. The results of polymerization on glass plate showed that the hydrophilic coatings cross-linked by BP(EGDMA) was more uniform and stable. The surface chemistry, wettability and permeability of membranes were further investigated. The results showed that coatings which used macromonomer BP(EGDMA) as cross-linker on porous membrane surface was still more uniform than those which used low molecular weight cross-linkers. Meanwhile, the effects of the irradiation time and monomer usage on membrane coatings were explored to choose the best fabrication condition. Under the suitable conditions, the membrane used BP(EGDMA) as cross-linker showed a high oil rejection of >99 % among several oil-in-water emulsion. Moreover, the anti-biofouling experiment revealed that the macromonomer BP(EGDMA) would endow hydrophilic coatings with better fouling resistance by longer irradiation time and larger total monomer usage. [ABSTRACT FROM AUTHOR]

Novel silicon-based liquid crystalline (LC) monomer (CASPA) and corresponding Poly(MMA)-b-Poly(CASPA) diblock copolymers (DBCs) containing symmetric azobenzene mesogens in the side chain were successfully synthesized by coupling reaction and reversible addition-fragmentation chain transfer (RAFT) polymerization, respectively. Block copolymerization by RAFT proceeded with well-controlled manner in anisole solution involving new CASPA monomer, Poly(MMA)-RAFT macroinitiator and AIBN initiator, yielding Poly(MMA)-b-Poly(CASPA) DBCs with excellent control over molecular weights (Mw/Mn ≤ 1.39) and compositions. Chemical structures and properties of CASPA and Poly(MMA)-b-Poly(CASPA) were extensively studied using 1H NMR, FTIR, GPC, DSC, POM, AFM and GISAXS. The CASPA exhibited enantiotropic liquid crystallinity with nematic four-brush schlieren texture, while DBCs showed monotropic liquid crystallinity with batonnet textures of smectic A phase. All DBC films exhibited photochemical trans -cis isomerization and photoinduced phase transition from mesophase to isotropic phase under UV irradiation. Morphologies of DBC thin films under thermal annealing depended on volume ratio of building LC block relative to Poly(MMA) segment, DBC-2 containing approximately equal block volume fractions self-assembled into lamellar nanostructure with domain-spacing of 34 nm, whereas DBC-3 and DBC-4 possessing higher LC contents (65 wt% and 72 wt%) formed highly ordered hexagonal cylindrical nanostructures with domain-spacing ranging from 37 to 39 nm as evidence by AFM and GI-SAXS, conforming with the self-consistent field theory. Novel AB-type liquid crystalline diblock azo copolymers (DBCs) with good control over their molecular weights, compositions and architectures, were synthesized from macroinitiator Poly(MMA)-RAFT and new silicon-containing acrylate monomer CASPA carrying paired azobenzene mesogens using RAFT polymerization. The DBCs exhibited low polydispersity index, monotropic liquid crystallinity with batonnet textures of smectic A phase, photochemical trans -cis isomerization and photoinduced phase transition from mesophase to isotropic phase upon UV irradiation. In addition, DBCs formed lamellar and hexagonal cylindrical nanostructures. Thus, synthesized DBCs can be deemed as promising candidate for photonics and nanolithography applications. [Display omitted] • Microphase-separated nanostructures in azo-based LCBCs by supramolecular cooperative motion. • Photoinduced phase transition of azo-based LCBCs from mesophase to isotropic phase upon UV irradiation. • Morphological nanostructures varied depending on composition of azo content in LCBCs. [ABSTRACT FROM AUTHOR]

This study investigates the potential of lignin as a sustainable alternative to petroleum-based polyols in the production of polyurethane-silica (PU-Si) coatings with improved tribological, anticorrosive and bactericidal properties. To achieve this goal, hybrid PU-Si coatings were developed and modified by incorporating varying amounts of lignin into the PU macromer chain, which were then applied to carbon steel substrates. Analysis through Fourier-transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance (13C NMR) analyses confirmed complete integration of the lignin into the PU chains. Additionally, 29Si NMR revealed that lignin incorporation acted to increase the condensation degree of the silica. Lignin had a smoothing effect in the hybrid coatings, leading to reduced roughness. Mechanical tests showed that the presence of lignin decreased the friction coefficients of the coatings, while enhancing their wear resistance and critical delamination loads, compared to the coating without lignin. The best PU-Si-lignin coating presented outstanding anticorrosive performance, achieving low-frequency impedance values up to 100 GΩ cm2, without failure for over 100 days. Furthermore, the incorporation of lignin inhibited E. coli biofilm formation. These multifunctional properties suggest that these coatings have promising applications across various industries, from infrastructure to healthcare. [Display omitted] • Explorer lignin as a renewable substitute for petroleum-based polyols in polyurethane-silica (PU-Si) coatings. • 29Si NMR analysis indicated that lignin incorporation increased the condensation degree of silica. • Lignin improved tribological, anticorrosive, and bactericidal properties of the coatings. • PU-Si-0.4Lig coating achieved low-frequency impedance values up to 100 GΩ cm2 and remained intact for over 100 days. • These coatings suggest potential uses in various sectors, including infrastructure and healthcare. [ABSTRACT FROM AUTHOR]

This paper aimed to produce a bio-based filament, suitable for 3D printing (fused deposition modeling), made of surface modified cellulose fiber and high density polyethylene. The cellulose fibers (CF) were first surface modified and transformed into a CF-based macroinitiator through an esterification reaction with the 2-bromoisobutyric acid. We finally studied the ability of this CF-based macroinitiator to initiate a single electron transfer-living radical polymerization (SET-LRP) with an hydrophobic monomer: the stearyl acrylate. The grafting of poly(stearly acrylate) onto the cellulose fibers did strongly increased the adhesion, compatibility of the modified fibers with the hydrophobic host matrix (HDPE). Finally, the resulting hydrophobic fibers were extruded with the high density polyethylene (HDPE) through a counter-rotating twin-screw extruder, yielding a bio-based filament suitable for FDM 3d printing. The successful surface modification, such as the correct incorporation of the modified fibers into the thermoplastic matrix, were characterized through ATR-FTIR, 13C CP-MAS NMR, FE-SEM, and mechanical testing. Throughout those characterization techniques, it was concluded that the fiber surface modification significantly improved the compatibility of the fibers with HDPE. Finally, the 3D printing properties of the composite were tested and compared to those of pure HDPE through the 3d printing of simple objects. It was concluded that the printability of the composite made with poly(stearyl acrylate)-grafted cellulose overcomes the problem (shrinkage, warpage, print fidelity) encountered with the printing of pure HDPE. [ABSTRACT FROM AUTHOR]

Chiral separation membranes have shown great potential for the efficient separation of racemic mixtures into enantiopure components for many applications, such as in the food and pharmaceutical industries; however, scalable fabrication of membranes with both high enantioselectivity and flux remains a challenge. Herein, enantiopure S‐poly(2,4‐dimethyl‐2‐oxazoline) (S‐PdMeOx) macromonomers were synthesized and used to prepare a new type of enantioselective membrane consisting of a chiral S‐PdMeOx network scaffolded by graphene oxide (GO) nanosheets. The S‐PdMeOx‐based membrane showed a near‐quantitative enantiomeric excess (ee) (98.3±1.7 %) of S‐(−)‐limonene over R‐(+)‐limonene and a flux of 0.32 mmol m−2 h−1. This work demonstrates the potential of homochiral poly(2,4‐disubstituted‐2‐oxazoline)s in chiral discrimination and provides a new route to the development of highly efficient enantioselective membranes using synthetic homochiral polymer networks. [ABSTRACT FROM AUTHOR]

Smart hydrogels are interesting materials as they can change their dimensions upon an external trigger. Herein, a photoresponsive double cross‐linked hydrogel system based on polyacrylamide (AAm) with grafted poly(2‐methyl‐2‐oxazoline) (PMOXA) chains with a α‐cyclodextrin/azobenzene host–guest complex is present. Switching azobenzene from the trans to the cis‐conformation through irradiation with UV light breaks the complex reversibly. Well‐defined PMOXA macromonomers have been synthesized and functionalized with the respective host and guest functionalities as well as double bonds for the incorporation into the polymer network as grafted side chains. The chemical structure of the macromonomers and the complex is confirmed by 1H NMR, 2D NOESY NMR, GPC, and UV–VIS measurements. Hydrogels with different ratios of permanent and photoresponsive cross‐linkers as well as different chain lengths of the PMOXA macromonomers are analyzed toward differences in their swelling/deswelling and elastic properties. Successive irradiation of supramolecular hydrogels with UV and VIS light allowed for a repeated swelling and de‐swelling of the hydrogels. This system is studied at both macro and micro scales, showing similar swelling tendencies. The tuned properties of photoresponsive double cross‐linked hydrogel makes this system a promising tool for various applications, for example, as in situ controllable valves in microfluidic flow cells. [ABSTRACT FROM AUTHOR]

Incorporation of photolabile moieties into the polymer backbone holds promise to remotely‐control polymer degradation. However, suitable synthetic avenues are limited, especially for radical polymerizations. Here we report a strategy to program photodegradability into vinylic polymers by exploiting the wavelength selectivity of photocycloadditions for radical ring‐opening polymerization (rROP). Irradiation of coumarin terminated allylic sulfides with UVA light initiated intramolecular [2+2] photocycloaddition producing cyclic macromonomers. Subsequent RAFT‐mediated rROP with methyl acrylate yielded copolymers that inherited the photoreactivity of the cyclic parent monomer. Irradiation with UVB initiated efficient photocycloreversion of the coumarin dimers, causing polymer degradation within minutes under UVB light or days under sunlight exposure. Our synthetic strategy may pave the way to insert photolabile linkages into vinylic polymers, tuning degradation for specific wavelengths. [ABSTRACT FROM AUTHOR]

Covalently bridged pillararene-based polymers (CBPPs) are a special class of macrocycle-based polymers in which multiple pillararene monomers are attached to the polymer structures by covalent bonds. Owing to the unique molecular structures including the connection components or the spatial structures, CBPPs have become increasingly popular in applications ranging from environmental science to biomedical science. In this review, CBPPs are divided into three types (linear polymers, grafted polymers, and cross-linked polymers) according to their structural characteristics and described from the perspective of synthesis methods comprehensively. In addition, the applications of CBPPs are presented, including selective adsorption and separation, fluorescence sensing and detection, construction of supramolecular gels, anticancer drug delivery, artificial light-harvesting, catalysis, and others. Finally, the current challenging issues and comprehensive prospects of CBPPs are discussed. [ABSTRACT FROM AUTHOR]

The paper presents the synthesis and characterization of star block copolymers based on polydimethylsiloxane and polycaprolactone. These copolymers were prepared by the ring opening polymerization of ε-caprolactone, using a single end type di-hydroxyalkyl terminated siloxane oligomer as macromonomer and stannous octoate as catalyst. Their chemical structures and molecular weights were characterized by 1H-NMR, FTIR and SEC, and thermal properties were determined by DSC. DSC analyses were also conducted to estimate the crystallinity degree of the PCL and PDMS blocks. [ABSTRACT FROM AUTHOR]

In this investigation, the synthesis of temperature‐responsive microgels containing high content of zwitterionic poly(phosphorylcholine) (PMPC) is reported. High loadings of polyzwitterionic chains are achieved by using PMPC‐based "macromonomers," which are synthesized via a three‐step reaction process. The first step involves synthesis of PMPC homopolymers via reversible addition fragmentation transfer (RAFT) polymerization, followed by end‐group removal to generate reactive thiol groups, and last of all, introduction of polymerizable double bonds at the chain ends to provide PMPC‐based macromonomers. Macromonomers of three different molar masses (3000, 5000, and 10 000 g mol−1) are used in three different molar ratios (1, 3, and 5 mol%) to synthesize microgels using N‐vinylcaprolactam (NVCL) as the main co‐monomer in precipitation polymerization. It is observed that the extent of total incorporation of the zwitterionic moiety is a function of both the macromonomer molar mass as well as its molar fraction in the feed which has a direct effect on their solution properties such as hydrodynamic radii and volume phase transition temperature (VPTT). Interestingly, these microgels show unprecedented extent of protein‐repelling behavior owing to higher loading of zwitterionic moieties, what makes them interesting for the fabrication of protective coatings with anti‐fouling properties. [ABSTRACT FROM AUTHOR]

The properties of polymer brushes based on three macromonomers were investigated in aqueous and organic solutions. Methacrylic monomers with different compositions of the oligo(oxyalkylene) substituents and arrangements of the oligo(ethylene glycol) and oligo(propylene glycol) blocks were used for the synthesis of polymers. There were methoxy [oligo(ethylene glycol)10.3-block-oligo(propylene glycol)4.7] methacrylate, methoxy [oligo(propylene glycol)8.3-block-oligo(ethylene glycol)6.6] methacrylate, and methoxy oligo(propylene glycol)4.2 methacrylate. Molecular brushes were investigated by the methods of molecular hydrodynamics and optics in dilute solutions in acetonitrile, chloroform, and water. The peculiarities of behavior of poly[oligo(oxyalkylene) methacrylates] in aqueous solutions and water-toluene systems have been found; in particular, the solubility of the polymers in water and organic solvents, the polymers equilibrium distribution between the phases, and the surface activity in the water-toluene system have been established. The thermo-responsibility in aqueous solutions and values of a critical concentration of micelle formation were shown. Depending on the arrangement of blocks in the side chains of molecular brushes, they are characterized by different intramolecular density. [ABSTRACT FROM AUTHOR]

This review aims at giving selected chemical and mechanical insights on design criteria that should be taken into account in hydrogel production for biomedical applications. Particular emphasis will be given to the chemical aspects involved in hydrogel design: macromer chemical composition, cross‐linking strategies and chemistry towards "conventional" and smart/stimuli responsive hydrogels. Mechanical properties of hydrogels in view of regenerative medicine applications will also be considered. [ABSTRACT FROM AUTHOR]

Featured Application: Stimuli-responsive hydrogels encompassing biobased polymers are anticipated for utilization in various fields, starting from drug delivery systems through temporal actuators and water reservoirs to biodegradable microelements and nutrient delivery depots. This paper describes the results of the radiation-induced crosslinking of polysaccharides modified with hydroxypropyl and carboxymethyl functional groups, hydroxypropylcellulose (HPC) and carboxymethylcellulose (CMC), respectively, without and with poly(ethylene glycol) diacrylate (PEGDA) as a crosslinking agent, to obtain dual stimuli-responsive hydrogels. The gels were characterized in terms of water uptake and gel fraction, parameters that mainly depend on the HPC–CMC compositions, but also on the macromer crosslinker content and the absorbed dose. The swelling of hydrogels is controlled by both the temperature, due to the amphiphilic character of HPC and pH, due to the anionic functional groups of CMC. In spite of a similar degree of substitution in both cellulose derivatives, 1.4 for HPC and 1.2 for CMC, the pH response of hydrogels with an equal content of both polysaccharides is considerably higher—a reduction in swelling of up to 95% with a decrease in the pH to 2 was recorded—than the response to thermal-stimulus—wherein a reduction in swelling of less than 70% with an increasing in temperature to 55 °C was found. These biopolymers-based hydrogels of specific, stimuli-responsive swelling properties are anticipated in applications where a combination of two stimuli is essential and biodegradation may be required. [ABSTRACT FROM AUTHOR]