journal
https://read.qxmd.com/read/38495389/unique-method-for-facile-postsynthetic-modification-of-nonisocyanate-polyurethanes
#1
JOURNAL ARTICLE
Sergei V Zubkevich, Maksim Makarov, Reiner Dieden, Laura Puchot, Vincent Berthé, Stephan Westermann, Alexander S Shaplov, Daniel F Schmidt
Nonisocyanate polyurethanes (NIPUs) are broadly investigated as a potential replacement for conventional polyurethanes (PUs) to eliminate the use of toxic isocyanates and reduce occupational hazards. One of the most popular approaches to NIPU synthesis is the polyaddition of cyclic bis(carbonate)s and diamines to form poly(hydroxyurethane)s (PHUs). However, such PHUs are highly hydrophilic due to the presence of two hydroxyl groups per repeat unit, and the resulting moisture absorption significantly degrades their thermomechanical performance and physical stability upon exposure to humidity, thus limiting their utility...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38495388/stereocomplexed-functional-and-statistical-poly-lactide-carbonate-s-via-a-simple-organocatalytic-system
#2
JOURNAL ARTICLE
Panagiotis Bexis, Jonathan T Husband, Haritz Sardon, Olivier Coulembier, Andrew P Dove
The stereocomplexation of polylactide (PLA) has been widely relied upon to develop degradable, sustainable materials with increased strength and improved material properties in comparison to stereopure PLA. However, forming functionalized copolymers of PLA while retaining high crystallinity remains elusive. Herein, the controlled ring-opening copolymerization (ROCOP) of lactide (LA) and functionalized cyclic carbonate monomers is undertaken. The produced polymers are shown to remain crystalline up to 25 mol % carbonate content and are efficiently stereocomplexed with homopolymer PLA and copolymers of opposite chirality...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38495387/investigation-of-the-effectiveness-of-photo-deprotection-of-polypeptides-in-solution-and-within-the-core-of-miniemulsion-derived-nanoparticles
#3
JOURNAL ARTICLE
Nicola Judge, Andreas Heise
Homopolymerization of ortho-nitrobenzyl ( o NB)-protected l-cysteine and l-glutamic acid was systematically studied in different solvents and at different monomer to initiator ratios, revealing the best reaction control in dimethylformamide (DMF) across a range of degrees of polymerization. In the subsequent ultraviolet (UV)-cleavage studies, it was found that quantitative deprotection upon UV exposure at 365 nm was not achievable for either of the homopolypeptides as confirmed by 1 H NMR and UV/visible (UV/vis) analyses...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38495386/controlling-the-optical-properties-of-transparent-auxetic-liquid-crystal-elastomers
#4
JOURNAL ARTICLE
Emily J Cooper, Matthew Reynolds, Thomas Raistrick, Stuart R Berrow, Ethan I L Jull, Victor Reshetnyak, Devesh Mistry, Helen F Gleeson
Determining the tunability of the optical coefficients, order parameter, and transition temperatures in optically transparent auxetic liquid crystal elastomers (LCEs) is vital for applications, including impact-resistant glass laminates. Here, we report measurements of the refractive indices, order parameters, and transition temperatures in a family of acrylate-based LCEs in which the mesogenic content varies from ∼50 to ∼85%. Modifications in the precursor mixture allow the order parameter, ⟨ P 2 ⟩, of the LCE to be adjusted from 0...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38495385/study-of-the-crystal-structure-and-hydrogen-bonding-during-cold-crystallization-of-poly-trimethylene-2-5-furandicarboxylate
#5
JOURNAL ARTICLE
Oscar Toledano, Oscar Gálvez, Mikel Sanz, Carlos Garcia Arcos, Esther Rebollar, Aurora Nogales, Mari Cruz García-Gutiérrez, Gonzalo Santoro, Izabela Irska, Sandra Paszkiewicz, Anna Szymczyk, Tiberio A Ezquerra
Here, we present a detailed description of the in situ isothermal crystallization of poly(trimethylene 2,5-furandicarboxylate)(PTF) as revealed by real-time Fourier transform infrared spectroscopy (FTIR) and grazing incidence wide-angle X-ray scattering (GIWAXS). From FTIR experiments, the evolution of hydrogen bonding with crystallization time can be monitored in real time, while from GIWAXS, crystal formation can be followed. Density functional theory (DFT) calculations have been used to simulate FTIR spectra for different theoretical structures, enabling a precise band assignment...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38495384/phase-behavior-and-conformational-asymmetry-near-the-comb-to-bottlebrush-transition-in-linear-brush-block-copolymers
#6
JOURNAL ARTICLE
Regina J Sánchez-Leija, Joshua A Mysona, Juan J de Pablo, Paul F Nealey
This study explores how conformational asymmetry influences the bulk phase behavior of linear-brush block copolymers. We synthesized 60 diblock copolymers composed of poly(trifluoroethyl methacrylate) as the linear block and poly[oligo(ethylene glycol) methyl ether methacrylate] as the brush block, varying the molecular weight, composition, and side-chain length to introduce different degrees of conformational asymmetry. Using small-angle X-ray scattering, we determined the morphology and phase diagrams for three different side-chain length systems, mainly observing lamellar and cylindrical phases...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38495383/solid-liquid-solution-phases-in-poly-diallyldimethylammonium-poly-acrylic-acid-polyelectrolyte-complexes-at-varying-temperatures
#7
JOURNAL ARTICLE
Chikaodinaka I Eneh, Kevin Nixon, Suvesh Manoj Lalwani, Maria Sammalkorpi, Piotr Batys, Jodie L Lutkenhaus
The coacervation and complexation of oppositely charged polyelectrolytes are dependent on numerous environmental and preparatory factors, but temperature is often overlooked. Temperature effects remain unclear because the temperature dependence of both the dielectric constant and polymer-solvent interaction parameter can yield lower and/or upper critical solution phase behaviors for PECs. Further, secondary interactions, such as hydrogen bonding, can affect the temperature response of a PEC. That is, mixtures of oppositely charged polyelectrolytes can exhibit phase separation upon lowering and/or increasing the mixture's temperature...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38495382/low-viscosity-route-to-high-molecular-weight-water-soluble-polymers-exploiting-the-salt-sensitivity-of-poly-n-acryloylmorpholine
#8
JOURNAL ARTICLE
Rory J McBride, Elisa Geneste, Andi Xie, Anthony J Ryan, John F Miller, Adam Blanazs, Christine Rösch, Steven P Armes
We report a new one-pot low-viscosity synthetic route to high molecular weight non-ionic water-soluble polymers based on polymerization-induced self-assembly (PISA). The RAFT aqueous dispersion polymerization of N -acryloylmorpholine (NAM) is conducted at 30 °C using a suitable redox initiator and a poly(2-hydroxyethyl acrylamide) (PHEAC) precursor in the presence of 0.60 M ammonium sulfate. This relatively low level of added electrolyte is sufficient to salt out the PNAM block, while steric stabilization is conferred by the relatively short salt-tolerant PHEAC block...
March 12, 2024: Macromolecules
https://read.qxmd.com/read/38435680/quantitative-model-of-multiple-crystal-growth-rate-minima-in-polymers-with-regularly-spaced-substituent-groups
#9
JOURNAL ARTICLE
Kutlwano Gabana, Gillian A Gehring, Xiangbing Zeng, Goran Ungar
A simple theory has been developed to explain quantitatively the multiple crystal growth rate minima observed experimentally in polyethylene brassylates (PEBs), polymers with regularly spaced "chemical defects", in this case, diester groups separated by 11 methylenes. The minima occur at the transitions where the fold length drops from 4 to 3 repeat units and from 3 to 2 units. An analytical rate-equation model was developed with elementary attachment and detachment steps of individual monomer repeat units, also including postattachment stem lengthening (stem conversion)...
February 27, 2024: Macromolecules
https://read.qxmd.com/read/38435679/molecular-mobility-and-gas-transport-properties-of-mixed-matrix-membranes-based-on-pim-1-and-a-phosphinine-containing-covalent-organic-framework
#10
JOURNAL ARTICLE
Farnaz Emamverdi, Jieyang Huang, Negar Mosane Razavi, Michael J Bojdys, Andrew B Foster, Peter M Budd, Martin Böhning, Andreas Schönhals
Polymers with intrinsic microporosity (PIMs) are gaining attention as gas separation membranes. Nevertheless, they face limitations due to their pronounced physical aging. In this study, a covalent organic framework containing λ5 -phosphinine moieties, CPSF-EtO, was incorporated as a nanofiller (concentration range 0-10 wt %) into a PIM-1 matrix forming dense films with a thickness of ca. 100 μm. The aim of the investigation was to investigate possible enhancements of gas transport properties and mitigating effects on physical aging...
February 27, 2024: Macromolecules
https://read.qxmd.com/read/38435678/degradable-and-multifunctional-peg-based-hydrogels-formed-by-iedda-click-chemistry-with-stable-click-induced-supramolecular-interactions
#11
JOURNAL ARTICLE
Nathan H Dimmitt, Chien-Chi Lin
The inverse electron demand Diels-Alder (iEDDA) reactions are highly efficient click chemistry increasingly utilized in bioconjugation, live cell labeling, and the synthesis and modification of biomaterials. iEDDA click reactions have also been used to cross-link tetrazine (Tz) and norbornene (NB) modified macromers [e.g., multiarm poly(ethylene glycol) or PEG]. In these hydrogels, Tz-NB adducts exhibit stable supramolecular interactions with a high hydrolytic stability. Toward engineering a new class of PEG-based click hydrogels with highly adaptable properties, we previously reported a new group of NB-derivatized PEG macromers via reacting hydroxyl-terminated PEG with carbic anhydride (CA)...
February 27, 2024: Macromolecules
https://read.qxmd.com/read/38370914/solid-phase-synthesis-as-a-tool-to-create-exactly-defined-branched-polymer-vectors-for-cell-membrane-targeting
#12
JOURNAL ARTICLE
Johanna K Elter, Veronika Liščáková, Oliver Moravec, Martina Vragović, Marcela Filipová, Petr Štěpánek, Pavel Šácha, Martin Hrubý
Modern drug formulations often require, besides the active drug molecule, auxiliaries to enhance their pharmacological properties. Tailor-made, biocompatible polymers covalently connected to the drug molecule can fulfill this function by increasing its solubility, reducing its toxicity, and guiding it to a specific target. If targeting membrane-bound proteins, localization of the drug close to the cell membrane and its target is beneficial to increase drug efficiency and residence time. In this study, we present the synthesis of highly defined, branched polymeric structures with membrane-binding properties...
February 13, 2024: Macromolecules
https://read.qxmd.com/read/38370913/proton-conducting-membranes-from-polyphenylenes-containing-armstrong-s-acid
#13
JOURNAL ARTICLE
Andy Künzel-Tenner, Christoph Kirsch, Oleksandr Dolynchuk, Leonard Rößner, Maxime Wach, Fabian Kempe, Thomas von Unwerth, Albena Lederer, Daniel Sebastiani, Marc Armbrüster, Michael Sommer
This study demonstrates the use of 1,5-naphthalenedisulfonic acid as a suitable building block for the efficient and economic preparation of alternating sulfonated polyphenylenes with high ion-exchange capacity (IEC) via Suzuki polycondensation. Key to large molar masses is the use of an all- meta -terphenyl comonomer instead of m -phenyl, the latter giving low molar masses and brittle materials. A protection/deprotection strategy for base-stable neopentyl sulfonates is successfully implemented to improve the solubility and molar mass of the polymers...
February 13, 2024: Macromolecules
https://read.qxmd.com/read/38370912/nanoscale-rheology-dynamic-mechanical-analysis-over-a-broad-and-continuous-frequency-range-using-photothermal-actuation-atomic-force-microscopy
#14
JOURNAL ARTICLE
Alba R Piacenti, Casey Adam, Nicholas Hawkins, Ryan Wagner, Jacob Seifert, Yukinori Taniguchi, Roger Proksch, Sonia Contera
Polymeric materials are widely used in industries ranging from automotive to biomedical. Their mechanical properties play a crucial role in their application and function and arise from the nanoscale structures and interactions of their constitutive polymer molecules. Polymeric materials behave viscoelastically, i.e., their mechanical responses depend on the time scale of the measurements; quantifying these time-dependent rheological properties at the nanoscale is relevant to develop, for example, accurate models and simulations of those materials, which are needed for advanced industrial applications...
February 13, 2024: Macromolecules
https://read.qxmd.com/read/38370911/keto-polyethylenes-with-controlled-crystallinity-and-materials-properties-from-catalytic-ethylene-co-norbornene-terpolymerization
#15
JOURNAL ARTICLE
Fabio De Stefano, Maximilian Baur, Claudio De Rosa, Stefan Mecking
Recent advances in Ni(II) catalyzed, nonalternating catalytic copolymerization of ethylene with carbon monoxide (CO) enable the synthesis of in-chain keto-functionalized polyethylenes (keto-PEs) with high-density polyethylene-like materials properties. Addition of norbornene as a bulky, noncrystallizable comonomer during catalytic polymerization allows tuning of the crystallinity in these keto-PE materials by randomly incorporated norbornene units in the polymer chain, while molecular weights are not adversely affected...
February 13, 2024: Macromolecules
https://read.qxmd.com/read/38370910/sequestration-of-small-ions-and-weak-acids-and-bases-by-a-polyelectrolyte-complex-studied-by-simulation-and-experiment
#16
JOURNAL ARTICLE
Roman Staňo, Jéré J van Lente, Saskia Lindhoud, Peter Košovan
Mixing of oppositely charged polyelectrolytes can result in phase separation into a polymer-poor supernatant and a polymer-rich polyelectrolyte complex (PEC). We present a new coarse-grained model for the Grand-reaction method that enables us to determine the composition of the coexisting phases in a broad range of pH and salt concentrations. We validate the model by comparing it to recent simulations and experimental studies, as well as our own experiments on poly(acrylic acid)/poly(allylamine hydrochloride) complexes...
February 13, 2024: Macromolecules
https://read.qxmd.com/read/38283123/photo-cross-linked-and-ph-switchable-soft-polymer-nanocapsules-from-polyglycidyl-ethers
#17
JOURNAL ARTICLE
Stefan Engel, Pascal M Jeschenko, Marcel van Dongen, Jonas C Rose, Dominic Schäfer, Michael Bruns, Sonja Herres-Pawlis, Helmut Keul, Martin Möller
Soft polymer nanocapsules and microgels, which can adapt their shape and, at the same time, sequester and release molecular payloads in response to an external trigger, are a challenging complement to vesicular structures like polymersomes. In this work, we report the synthesis of such capsules by photo-cross-linking of coumarin-substituted polyglycidyl ethers, which we prepared by Williamson etherification of epichlorohydrin (ECH) repeating units with 7-hydroxycoumarin in copolymers with tert -butyl glycidyl ether ( t BGE)...
January 23, 2024: Macromolecules
https://read.qxmd.com/read/38283122/effect-of-polyelectrolyte-charge-density-on-the-linear-viscoelastic-behavior-and-processing-of-complex-coacervate-adhesives
#18
JOURNAL ARTICLE
Larissa van Westerveld, Théophile Pelras, Anton H Hofman, Katja Loos, Marleen Kamperman, Julien Es Sayed
It is well-known that the phase behavior and physicochemical and adhesive properties of complex coacervates are readily tuneable with the salt concentration of the medium. For toxicity reasons, however, the maximum applicable salt concentration in biomedical applications is typically low. Consequently, other strategies must be implemented in order to optimize the properties of the resulting complex coacervates. In this work, the effect of the charge density of a strong polyanion on the properties of complex coacervates was studied...
January 23, 2024: Macromolecules
https://read.qxmd.com/read/38222028/exponential-vs-gaussian-correlation-functions-in-the-characterization-of-block-copolymer-grain-structure-by-depolarized-light-scattering
#19
JOURNAL ARTICLE
Xin Wang, Jacob L Thelen, Xiuhong Li, Nitash P Balsara, Bruce A Garetz
Block copolymer (BCP) grain structure affects the mechanical, optical, and electrical properties of BCP materials, making the accurate characterization of this grain structure an important goal. In this study, improved BCP grain parameters were obtained by employing an exponentially decaying correlation function within the ellipsoidal grain model, instead of the Gaussian correlation function that was used in previous work. The exponential correlation function provides a better fit to the experimental depolarized light scattering data, which outweighs the disadvantage that it requires numerical integration to obtain the model scattered intensity...
January 9, 2024: Macromolecules
https://read.qxmd.com/read/38222027/synthesis-of-poly-propylene-oxide-poly-n-n-dimethylacrylamide-diblock-copolymer-nanoparticles-via-reverse-sequence-polymerization-induced-self-assembly-in-aqueous-solution
#20
JOURNAL ARTICLE
Matthew A H Farmer, Osama M Musa, Iris Haug, Stefan Naumann, Steven P Armes
Sterically-stabilized diblock copolymer nanoparticles comprising poly(propylene oxide) (PPO) cores are prepared via reverse sequence polymerization-induced self-assembly (PISA) in aqueous solution. N,N '-Dimethylacrylamide (DMAC) acts as a cosolvent for the weakly hydrophobic trithiocarbonate-capped PPO precursor. Reversible addition-fragmentation chain transfer (RAFT) polymerization of DMAC is initially conducted at 80% w/w solids with deoxygenated water. At 30-60% DMAC conversion, the reaction mixture is diluted to 5-25% w/w solids...
January 9, 2024: Macromolecules
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