Covalent triazine‐based frameworks (CTFs) with a graphene‐like layered morphology have been controllably synthesized by the trifluoromethanesulfonic acid‐catalyzed nitrile trimerization reactions at room temperature via selecting different monomers. Platinum nanoparticles are well dispersed in CTF‐T1, which is ascribed to the synergistic effects of the coordination of triazine moieties and the nanoscale confinement effect of CTFs. CTF‐T1 exhibits excellent photocatalytic activity and stability for H2 evolution in the presence of platinum under visible light irradiation (λ ≥ 420 nm). The activity and stability of CTF‐T1 are comparable to those of g‐C3N4. Importantly, as a result of the tailorable electronic and spatial structures of CTFs that can be achieved through the judicial selection of monomers, CTFs not only show great potential as organic semiconductor for photocatalysis but also may provide a molecular‐level understanding of the inherent heterogeneous photocatalysis.
An alkyne‐functionalized ruthenium(II) bis‐terpyridine complex is directly copolymerized with phenylacetylene by alkyne polymerization. The polymer is characterized by size‐exclusion chromatography (SEC), 1H NMR spectroscopy, cyclic voltammetry (CV) measurements, and thermal analysis. The photophysical properties of the polymer are studied by UV–vis absorption spectroscopy. In addition, spectro‐electrochemical measurements are carried out. Time‐resolved luminescence lifetime decay curves show an enhanced lifetime of the metal complex attached to the conjugated polymer backbone compared with the Ru(tpy)22+ model complex.
A novel method, epoxidation/reduction of vegetable oils, is developed to prepare bio‐based polyols for the manufacture of polyurethanes (PUs). These polyols are synthesized from castor oil (CO), epoxidized soybean oil, and epoxidized linseed oil and their molecular structures are characterized. They are used to prepare a variety of PUs, and their thermomechanical properties are compared to those of PU made with petroleum‐based polyol (P‐450). It is shown that PUs made with polyols from soybean and linseed oil exhibit higher glass transition temperatures, tensile strength, and Young's modulus and PU made with polyol from CO exhibits higher elongation at break and toughness than PU made with P‐450. However, PU made with P‐450 displays better thermal resistance because of tri‐ester structure and terminal functional groups. The method provides a versatile way to prepare bio‐polyols from vegetable oils, and it is expected to partially or completely replace petroleum‐based polyols in PUs manufacture.
A novel strategy for the incorporation of carbon dioxide into polymers is introduced. For this purpose, the Ugi five‐component condensation (Ugi‐5CC) of an alcohol, CO2, an amine, an aldehyde, and an isocyanide is used to obtain step‐growth monomers. Polymerization via thiol‐ene reaction or polycondensation with diphenyl carbonate gives diversely substituted polyurethanes or alternating polyurethane‐polycarbonates, respectively. Furthermore, the application of 1,12‐diaminododecane and 1,6‐diisocyanohexane as bifunctional components in the Ugi‐5CC directly results in the corresponding polyamide bearing methyl carbamate side chains ( = 19 850 g mol−1). The latter polymer is further converted into the corresponding polyhydantoin in a highly straightforward fashion.
Hybrids with a silica network covalently bonded to a polymer are promising materials for bone repair. Previous work on synthesizing methyl methacrylate (MMA) based copolymers by reversible addition‐fragmentation chain transfer (RAFT) polymerization gives high tailorability of mechanical properties since sophisticated polymer structures can be designed. However, more flexible hybrids would be beneficial. Here, n‐butyl methacrylate (BMA) and methyl acrylate (MA) based hybrids are produced. Unlike MMA, BMA and MA hybrids do not show plastic deformation, and BMA hybrid has strain to failure of 33%. Although the new hybrids are more flexible, preosteoblast cells do not adhere on their surfaces, due to higher hydrophobicity and lower stiffness. Comonomer choice is crucial for bone regenerative hybrids.
A simple polymerization of trichlorophosphoranimine (Cl3P = N−SiMe3) mediated by functionalized triphenylphosphines is presented. In situ initiator formation and the subsequent polymerization progress are investigated by 31P NMR spectroscopy, demonstrating a living cationic polymerization mechanism. The polymer chain lengths and molecular weights of the resulting substituted poly(organo)phosphazenes are further studied by 1H NMR spectroscopy and size exclusion chromatography. This strategy facilitates the preparation of polyphosphazenes with controlled molecular weights and specific functional groups at the α‐chain end. Such well‐defined, mono‐end‐functionalized polymers have great potential use in bioconjugation, surface modification, and as building blocks for complex macromolecular constructs.
The junction dynamics in a selectively deuterated model polymer network containing junctions on every 21st chain carbon is studied by solid state 2H echo NMR. Polymer networks are prepared via acyclic triene metathesis of deuteron‐labeled symmetric trienes with deuteron probes precisely placed at the alpha carbon relative to the junction point. The effect of decreasing the cross‐link density on the junction dynamics is studied by introduction of polybutadiene chains in‐between junctions. The networks are characterized by swelling, gel content, and solid state 1H MAS NMR. Line shape analysis of the 2H quadrupolar echo spectra reveals that the degree of motion anisotropy and the distribution of motion correlation times depend on the cross‐link density and structural heterogeneity of the polymer networks. A detailed model of the junction dynamics at different temperatures is proposed and explained in terms of the intermolecular cooperativity in densely‐packed systems.
High‐molecular‐weight conjugated polymer HD‐PDFC‐DTBT with N‐(2‐hexyldecyl)‐3,6‐difluorocarbazole as the donor unit, 5,6‐bis(octyloxy)benzothiadiazole as the acceptor unit, and thiophene as the spacer is synthesized by Suzuki polycondensation. HD‐PDFC‐DTBT shows a large bandgap of 1.96 eV and a high hole mobility of 0.16 cm2 V−1 s−1. HD‐PDFC‐DTBT:PC71BM‐based inverted polymer solar cells (PSCs) give a power conversion efficiency (PCE) of 7.39% with a Voc of 0.93 V, a Jsc of 14.11 mA cm−2, and an FF of 0.56.
Triptycene‐based micorporous polymer is functionalized with CO2‐philic tetrazole moieties via ZnCl2‐catalyzed post‐polymerization. Gas adsorption experiments indicate that it possesses high CO2 uptake capacity, reaching 134 cm3 g−1 (26.5 wt%) at 1.0 bar and 273 K, along with high selectivity towards CO2 over N2 and CH4. The porous polymeric networks present the promising potentials as efficient adsorbents in clean energy applications.
Sodium alginate (SA), acting as a trypsin inhibitor by means of electrostatic interaction, is studied. The half‐maximal inhibitory concentration (IC50 = 0.05 μg mL−1) of this natural anionic polymer is about 400 times lower than that of commercial soybean trypsin inhibitor (STI). Unlike the Ca2+‐deprivation mechanisms, its inhibition may be attributed to preventing the trypsin active site (TAS) from accessing the macromolecular substrates instead of denaturing it. SA is an efficient, innocuous, and cost‐effective inhibitory excipient that can be conveniently used in many peptide and protein dosage formulations.
A novel diblock copolymer consisting of poly(vinylferrocene) (PVFc) and poly(N,N‐diethylacrylamide) (PDEA) is synthesized via a combination of anionic and RAFT polymerization. The use of a novel route to hydroxyl‐end‐functionalized metallopolymers in anionic polymerization and subsequent esterification with a RAFT agent leads to a PVFc macro‐CTA ( = 3800 g mol−1; Đ = 1.17). RAFT polymerization with DEA affords block copolymers as evidenced by 1H NMR spectroscopy as well as size exclusion chromatography (6400 ≤ ≤ 33700 g mol−1; 1.31 ≤ Đ 1.28). Self‐assembly of the amphiphilic block copolymers in aqueous solution leads to micelles as shown via TEM. Importantly, the distinct thermo‐responsive and redox‐responsive character of the blocks is probed via dynamic light scattering and found to be individually and repeatedly addressable.
Copolymers of 2‐(methacrylamido)glucopyranose (MAG) and methacrylic acid (MAA) are synthesized by RAFT polymerization and then used as templates to prepare glycopolymer‐functionalized Ag nanoclusters (Gly‐Ag NCs) through microwave irradiation. Polymers and the resulting nanoclusters are characterized by NMR, GPC, UV‐Vis, SEM, TEM, AAS and fluorescence spectroscopy. The bio‐activity of the fluorescent Gly‐Ag NCs are further examined using GLUT‐1 over‐expressing cancer cells K562. Gly‐Ag NCs show efficient binding ability toward K562 cells and inhibit the cell viability in a dose dependent manner (IC50 = 0.65 μg mL–1), indicating their potential biological applications for both cancer imaging and targeted cancer therapy.
The controlled folding of a single polymer chain is for the first time realized by metal‐ complexation. α,ω‐Bromine functional linear polymers are prepared via activators regenerated by electron transfer (ARGET) ATRP (,SEC = 5900 g mol−1, Đ = 1.07 and 12 000 g mol−1, Đ = 1.06) and the end groups of the polymers are subsequently converted to azide functionalities. A copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction is carried out in the presence of a novel triphenylphosphine ligand and the polymers to afford homotelechelic bis‐triphenylphosphine polymeric‐macroligands (MLs) (,SEC = 6600 g mol−1, Đ = 1.07, and 12 800 g mol−1, Đ = 1.06). Single‐chain metal complexes (SCMCs) are formed in the presence of Pd(II) ions in highly diluted solution at ambient temperature. The results derived via 1H and 31P{1H} NMR experiments, SEC, and DLS unambiguously evidence the efficient formation of SCMCs via metal ligand complexation.
Injectable hydrogels have been commonly used as drug‐delivery vehicles and tried in tissue engineering. Injectable self‐healing hydrogels have great advantage over traditional injectable hydrogels because they can be injected as a liquid and then rapidly form bulk gels in situ at the target site under physiological conditions. This study develops an injectable thermosensitive self‐healing hydrogel based on chain‐extended F127 (PEO90‐PPO65‐PEO90) multi‐block copolymer (m‐F127). The rapid sol–gel transition ability under body temperature allows it to be used as injectable hydrogel and the self‐healing property allows it to withstand repeated deformation and quickly recover its mechanical properties and structure through the dynamic covalent bonds. It is hoped that the novel strategy and the fascinating properties of the hydrogel as presented here will provide new opportunities with regard to the design and practical application of injectable self‐healing hydrogels.
Well‐defined poly(2,5‐dihexyloxyphenylene‐1,4‐diyl) (PPP) is successfully synthesized by the Negishi catalyst‐transfer polycondensation (NCTP) using dilithium tetra(tert‐butyl)zincate (tBu4ZnLi2). The obtained PPP possesses the number‐averaged molecular weight (M n) values in the range of 2100–22 000 and the molar‐mass dispersity (Ð M) values in the range of 1.09–1.23. In addition, block copolymers containing PPP and poly(3‐hexylthiophene) (P3HT) segments (PPP‐b‐P3HT) are synthesized to confirm the feasibility of chain extension between the different monomers based on NCTP.
The preparation of multifunctional polymers and block copolymers by a straightforward one‐pot reaction process that combines enzymatic transacylation with light‐controlled polymerization is described. Functional methacrylate monomers are synthesized by enzymatic transacylation and used in situ for light‐controlled polymerization, leading to multifunctional methacrylate‐based polymers with well‐defined microstructure.
The chemical control of cell division has attracted much attention in the areas of single cell‐based biology and high‐throughput screening platforms. A mussel‐inspired cytocompatible encapsulation method for achieving a “cell‐division control” with cross‐linked layer‐by‐layer (LbL) shells is developed. Catechol‐grafted polyethyleneimine and hyaluronic acid are chosen as polyelectrolytes for the LbL process, and the cross‐linking of polyelectrolytes is performed at pH 8.5. Cell division is controlled by the number of the LbL nanolayers and cross‐linking reaction. We also suggest a new measuring unit, , for quantifying “cell‐division timing” based on microbial growth kinetics.
Composite nanoparticles from poly[(9,9‐di‐n‐octylfluoren‐2,7‐diyl)‐alt‐(benzo[2,1,3]thiadiazol‐4,8‐diyl)] (F8BT) and poly(9,9‐di‐n‐hexylfluoren‐2,7‐diyl) (PF) with embedded inorganic nanoparticles (TiO2, CdSe, and CdSe/CdS) are prepared through kinetic trapping by rapid turbulent mixing in a multi‐inlet vortex mixer without the need for polymer functionalization. High contents of inorganic materials up to 50–60 wt% are realized for all composites. The influence of flow ratios, sodium dodecyl sulfate (SDS) concentration, and absolute flow rates on the particle size and morphology is studied. High water‐to‐THF ratios and high total flow rates around 2 m s−1 yield particle sizes below 50 nm. By adjusting these parameters, controlled particle sizes between 30 to several hundred nanometers are obtained. Composite particles from CdSe/CdS and F8BT or PF show a strong quenching of the polymer emission and near exclusive emission from the inorganic nanocrystal, which indicates an efficient energy transfer with fluorescence quantum yields of 23% for the F8BT/CdSe/CdS composites and 21% for the PF/CdSe/CdS composites. The dispersions are colloidally stable for several months.
In this work, the synthesis of various halogenated thiophenol derivatives is presented. These thiophenols are used as monomers in light‐initiated SRN1‐type radical polymerization reactions. The method provides easy access to industrially relevant poly(paraphenylene sulfide) and poly(metaphenylene sulfide). The influence of the halide leaving group and of other substituents in the thiophenol monomer on the polymerization process is investigated.
A commercially available palladium N‐heterocyclic carbene (Pd‐NHC) precatalyst is used to initiate chain‐growth polymerization of 2‐bromo‐3‐hexyl‐5‐trimethylstannylthiophene. The molecular weight of the resultant poly(3‐hexylthiophene) can be modulated (7 to 73 kDa, Đ = 1.14 to 1.53) by varying the catalyst concentration. Mass spectrometry data confirm control over the polymer end groups and 1H NMR spectroscopy reveals that the palladium catalyst is capable of “ring‐walking”. A linear relationship between Mn and monomer conversion is observed. Atomic force microscopy and X‐ray scattering verify the regioregular nature of the resultant polythiophene.
