Ladder polymer

The reaction of preassembled Cu(I) bimetallic units {Cu2 (dppm)2 } and {Cu2 (dppa)2 } (dppm: bis(diphenylphosphino)methane and dppa: bis(diphenylphosphino)amine) with pseudohalide linkers (azido, dicyanamide, and tricyanomethanide) allows for the quantitative and selective preparation of three discrete tetrametallic metallacycles of formula [Cu4 (μ2 -dppm)4 (N3 )2 ](PF6 )2 , [Cu4 (μ2 -dppm)4 (N(CN)2 )2 ](PF6 )2 , and [Cu4 (μ2 -dppm)4 (C(CN)3 )4 ]. To explore further the impact of the linker on the architecture and dimensionality of the molecular edifice, the study was extended to more sophisticated tetradentate cyanocarbanion ligands (tcnsMe- : 2-(methylthio)-1,1,3,3-propanetetracarbonitrile and tcnsEt- : 2-(ethylthio)-1,1,3,3-propanetetracarbonitrile)...

In this study, thiol-functionalized ladder-like polysesquioxanes end-capped with methyl and phenyl groups were synthesized via a simple sol-gel method and characterized through gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). Additionally, epoxy blends of different formulations were prepared. Their structural, flame-retardant, thermal, and mechanical properties, as well as volatile organic compound (VOC) emissions, were determined using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), TGA, scanning electron microscopy (SEM), limiting oxygen index (LOI), cone calorimetry, and a VOC analyzer...

Organic electrochemical transistors (OECTs) are one of the promising building blocks to realize next-generation bioelectronics. To date, however, the performance and signal processing capabilities of these devices remain limited by their stability and speed. Herein, we demonstrate a stable and fast n-type organic electrochemical transistors based on a side-chain-free ladder polymer, poly(benzimidazoanthradiisoquinolinedione). The device demonstrated fast normalized transient speed of 0.56 ± 0.17 ms/um2 and excellent long-term stability in aqueous electrolytes, with no significant drop in its doping current after 50,000 successive doping/dedoping cycles and 2 months storage at ambient conditions...

In polyolefins, long-chain branching is introduced through an energy-intensive, high-pressure radical process to form low-density polyethylene (LDPE). In the current work, we demonstrated a ladder-like polyethylene architecture through solution polymerization of ethylene and less than 1 mole % of α,ω-dienes, using a dual-chain catalyst. The ladder-branching mechanism requires catalysts with two growing polymer chains on the same metal center, thus enchaining the diene without the requirement of a steady-state concentration of pendant vinyl groups...

Ladder systems situated in the dimensional crossover region have attracted much attention because their electronic states and physical properties depend strongly on the electronic correlations among the constituent legs. Generally, two-/three-legged transition metal-oxide ladder compounds are studied as representative ladder systems, but two-/three-dimensional (2D/3D) extensions based on such ladder systems with a few numbers of legs are difficult because of the extreme synthesis conditions. Here, for the first time, we report the successful creation of a 3D extended two-legged ladder compound, [Pt(en)(dpye)I]2(NO3)4·2H2O (en = ethylenediamine; dpye = 1,2-Di(4-pyridyl)ethane), which is obtained by simple oxidative polymerization of a small Pt macrocyclic complex using elemental I2...

Synthetic breakthroughs diversify the molecules and polymers available to chemists. We now report the first successful synthesis of a series of optically-pure 2,2´-tethered binaphthyl-embedded helical ladder polymers based on quantitative and chemoselective ladderization by the modified alkyne benzannulations using the 4-alkoxy-2,6-dimethylphenylethynyl group as the alkyne source, inaccessible by the conventional approach lacking the 2,6-dimethyl substituents. Due to the defect-free helix formation, the circular dichroism signal increased by more than 6 times the previously reported value...

We synthesized and characterized two isomeric microporous hydrocarbon ladder polymers from catalytic arene norbornene annulation (CANAL) of regioisomeric bis-norbornene fused spirobifluorenes, where the ladder chains are connected either through the same fluorene unit or across two different fluorene units in spirobifluorene. This pair of isomeric polymers was used to investigate the effect of ladder macromolecular structures on the microporosity and transport properties. Both polymers form mechanically intact films with thermal stability up to 480 °C and relatively high BET surface areas...

The synthesis of single-crystal, one-dimensional (1D) polymers is of great importance but a formidable challenge. Herein, we report the synthesis of single-crystal 1D ladder polymers in solution by dynamic covalent chemistry. The three-dimensional electron diffraction technique was used to rigorously solve the structure of the crystalline polymers, unveiling that each polymer chain is connected by double covalent bridges and all polymer chains are packed in a staggered and interlaced manner by π-π stacking and hydrogen bonding interactions, making the crystalline polymers highly robust in both thermal and chemical stability...

Superglassy membranes synthesised by polymers of intrinsic microporosity (PIMs) suffer from physical aging and show poor gas permeance over time, especially thin membranes, due to the fast rearrangement of nonequilibrium polymer chains. Herein, we constructed a novel PIM-1 thin film nanocomposite membrane (TFN) using nanosized UiO-66-NH2 (~10 nm)/carboxylated PIM-1 (cPIM-1) as the composite filler. Unlike conventional fillers, which interact with the polymer only via the surface, the UiO-66-NH2/cPIM-1 forms a stable three-dimensional (3D) network intertwining with the polymer chains, being very effective to impede chain relaxation, and thus physical aging...

Structure and reversibility of cross-link junctions play pivotal roles in determining the nature of thermoreversible gelation and dynamic mechanical properties of the produced polymer networks. We attempt to theoretically explore new types of sol-gel transitions with mechanical sharpness by allowing cross-links to grow without upper bound. We consider thermoreversible gelation of the primary molecules R{Af} carrying the number f of low molecular weight functional groups (gelators) A. Gelators A are assumed to form supramolecular assemblies...

Ladder-like poly(methacryloxypropyl)-silsesquioxanes (LPMASQ) are photocurable Si-based gels characterized by a double-stranded structure that ensures superior thermal stability and mechanical properties than common organic polymers. In this work, these attractive features were exploited to produce, in combination with alumina nanoparticles (NPs), both unmodified and functionalized with methacryloxypropyl-trimethoxysilane (MPTMS), LPMASQ/Al2 O3 composites displaying remarkable thermal conductivity. Additionally, we combined LPMASQ with polybutadiene (PB) to produce hybrid nanocomposites with the addition of functionalized Al2 O3 NPs...

A one-dimensional (1D) ladder-like coordination polymer {NH4 [{Cu(bpy)}2 (C2 O4 )Fe(C2 O4 )3 ]·H2 O} n ( 1 ; bpy = 2,2'-bipyridine) containing [Cu(bpy)(μ-C2 O4 )Cu(bpy)]2+ cationic units linked by oxalate groups of [Fe(C2 O4 )3 ]3- building blocks was investigated as a new type of photoactive solid-state system. It exhibits a photocoloration effect when exposed to direct sunlight or UV/vis irradiation. The photochromic properties and mechanism were studied by powder and single-crystal X-ray diffraction, UV/vis diffuse reflectance, IR and electron paramagnetic resonance spectroscopy, magnetization and impedance measurements, and density functional theory calculations...

Organic semiconductors can afford detection at wavelengths beyond commercial silicon photodetectors. However, for each targeted near-infrared wavelength range, this requires individually optimized materials, which adds to the complexity and costs. Moreover, finding molecules with strong absorption beyond 1 μm that perform well in organic photodetectors remains a challenge. In microcavity devices, the detection window can be extended to wavelengths inaccessible for silicon without the need for new materials by adopting an intelligent design...

Ladder polymers with poly(diketopyrrolopyrrole) (DPP) moieties have recently attracted enormous interest for a large variety of opto-electronic applications. Since the rigidity of the backbone increases with ladderization, a strong influence on the self-organization of thin films is expected. We study the molecular orientation of DPP-based ladder polymers in about 50 nm thin films using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS). Exemplarily, for one polymer, the orientation in thicker films is qualitatively investigated by infrared spectroscopy in transmission...

Electrochemical proton storage plays an essential role in designing next-generation high-rate energy storage devices, e.g., aqueous batteries. Two-dimensional conjugated covalent organic frameworks (2D c-COFs) are promising electrode materials, but their competitive proton and metal-ion insertion mechanisms remain elusive, and proton storage in COFs is rarely explored. Here, we report a perinone-based poly(benzimidazobenzophenanthroline) (BBL)-ladder-type 2D c-COF for fast proton storage in both a mild aqueous Zn-ion electrolyte and strong acid...

The synthesis of ladder-type 9,9'-bifluorenylidene-based conjugated polymer is reported. Unlike the typical synthetic strategy, the new designed ladder-type conjugated polymer is achieved via tandem Suzuki polymerization/Heck cyclization reaction in one-pot. In the preparation process, Suzuki polymerization reaction occurred first and then the intramolecular Heck cyclization followed smoothly under the same catalyst Pd(PPh3 )4 . The model reaction proved that the introduction of iodine (I) for this tandem reaction can effectively control the sequential bond-forming process and inhibit the additional competitive side reactions...

Replacement or debottlenecking of the extremely energy-intensive cryogenic distillation technology for the separation of ethylene from ethane has been a long-standing challenge. Membrane technology could be a desirable alternative with potentially lower energy consumption. However, the current key obstacle for industrial implementation of membrane technology is the low mixed-gas selectivity of polymeric, inorganic or hybrid membrane materials, arising from the similar sizes of ethylene (3.75 Å) and ethane (3...

The ladder phenyl/vinyl polysilsesquioxane (PhVPOSS) was used to improve the flame-retardancy performances of ethylene-vinyl acetate copolymer (EVA)/aluminum hydroxide (ATH) composites due to the reactivity of its vinyl groups. FTIR, XPS, 1 H NMR, and SEM-EDS data demonstrated the PhVPOSS grafting onto EVA molecular chains. The PhVPOSS improved the thermal stability of EVA/ATH composites, as shown by the thermogravimetric analysis (TGA). Furthermore, with the cone calorimeter (CONE) experiments, EVA/ATH/PhVPOSS showed better fire safety than the EVA/ATH composites, with the PHRR, PSPR, and PCOP reduced by 7...

In order to expand the range of materials that can be used in outer space and in development of small spacecraft, ladder polyphenylsilsesquioxanes with different molar weights and the Nb-siloxane composites based on them were studied. The properties of the polymer films were studied, including tests in an oxygen plasma flow. Both initial and filled ladder polymers feature extremely low erosion coefficients in the region of 10-26 cm3 /atom O at a high fluence of atomic oxygen of 1.0 × 1021 atom O/cm2 . Ladder polyphenylsilsesquioxane films irradiated with atomic oxygen (AO) retain their integrity, do not crack, and exhibit good optical properties, in particular, a high transmittance...

This paper presents the results of studies on the pervaporation properties (for benzene/hexane mixtures) and gas permeability (for He, H2 , N2 , O2 , CO2 , CH4 , C2 H6 , and C4 H10 ) of ladder-like polyphenylsesquioxanes (L-PPSQ) with improved physical and chemical properties. These polymers were obtained by condensation of cis -tetraphenylcyclotetrasiloxanetetraol in ammonia medium. The structure of L-PPSQ was fully confirmed by a combination of physicochemical analysis methods: 1 H, 29 Si NMR, IR spectroscopy, HPLC, powder XRD, and viscometry in solution...