Three-dimensional Polymer Research Articles

Safe and Energy-Dense Flexible Solid-State Lithium–Oxygen Battery with a Structured Three-Dimensional Polymer Electrolyte

Safe and Energy-Dense Flexible Solid-State Lithium–Oxygen Battery with a Structured Three-Dimensional Polymer Electrolyte

A solid hydrogel electrolyte-based micro fuel cell integrated with fuel/electrolyte storage and supply function

<p indent="0mm">The development of modern electronic equipment has promoted the requirement of portable energy conversion devices. Fuel cell technology provides clean energy, which is pollution-free and environmentally friendly. It has several advantages, including instant charge and discharge, high energy conversion efficiency, and easy integration. However, some disadvantages, such as high membrane cost, membrane aging degradation, water management, and extra ohmic resistance, always accompany the conventional proton exchange membrane fuel cells. In addition, the need for fuel tanks increases the system cost and complexity and is unfavorable for miniaturization. Meanwhile, the consumption of additional pump power to supply fuel can reduce the net output power. Hydrogel is a solid-state electrolyte crosslinked via a three-dimensional (3D) polymer network. The porous structure possesses the abilities of water absorption and retention and enables fast mass transport on a large surface. To simplify the fuel cell system and improve its portability, a miniature fuel cell integrated with the fuel/electrolyte is proposed, complemented by the water retention and ionic conductivity of the hydrogel. Polyvinyl alcohol (PVA) hydrogel is prepared via cyclic freezing and thawing processes. The effects of the fabrication parameters, such as swelling and conductivity of the hydrogel electrolyte, are discussed, and the fuel cell equipped with hydrogel is set up. The micromorphology and element distribution of PVA hydrogel are evaluated via physical characterization. PVA hydrogel has an abundant 3D-network porous structure. PVA polymer chain is uniformly crosslinked, and C and O elements are evenly distributed on the hydrogel skeleton. Fourier transform infrared results reveal numerous hydrophilic groups in PVA hydrogel, including –OH and C–O, contributing to the high aqueous electrolyte absorption ability. The effect of fabrication parameters on the swelling properties of PVA hydrogel is studied. The high concentration and efficient repetitive freezing-thawing can improve the crosslinking density of the PVA hydrogel, firmness of the hydrogel skeleton, and swelling equilibrium. The PVA hydrogel in 5% can reach the maximum swelling ratio of 45%. The ionic conductivity of the PVA hydrogel after swelling the electrolyte is studied via the two-probe AC impedance method. The various freezing-thawing cycles have an evident influence on the crosslinking density and pore size of the hydrogel, contributing to the absorption ability of the sulfuric acid solution and hydrogel conductivity. The ionic conductivity of the PVA hydrogel in 5% by three freeze-haw cycles is up to 173.61 mS/cm, facilitating the hydrogen ion conduction in the fuel cell. Moreover, the effects of hydrogel thickness, fuel concentration, and electrolyte concentration on the fuel cell performance are studied. Consequently, when the hydrogel electrolyte thickness is <sc>6 mm</sc> using <sc>6 mol/L</sc> HCOOH and <sc>1 mol/L</sc> H₂SO₄, the maximum power density is <sc>2.5 mW/cm²</sc>, and the limiting current density is <sc>15.2 mA/cm².</sc> The results suggest that the fuel cell can be used to power miniature portable electronic devices.

Development of green photocatalytic geopolymers for dye removal

The use of photocatalysts for water and air depollution processes that utilize light irradiation as an energy source is a well-known and popular research field. Geopolymers, as new sustainable three-dimensional porous inorganic polymers that have the potential to be tailored and used in different applications, are a novel promising candidate as adsorbent and catalyst for depollution applications. In this study, new green geopolymer photocatalysts were developed using rice husk, rice husk ash, metakaolin, ground granulated blast furnace slag, palm oil fuel ash, and TiO2. The depollution performance of the prepared TiO2-based geopolymers was evaluated using the methylene blue (MB) removal test; the geopolymers exhibited more than 95% efficiency in optimum conditions. Artificial neural network (ANN) was employed to predict the adsorption efficiency/capacity of MB adsorption on the developed geopolymer photocatalyst. The proposed ANN model performed well for the adsorption experimental dataset. MB adsorption on the geopolymer photocatalyst was optimized, and different kinetic theories were applied to the experimental data. The pseudo-second-order model explained the adsorption kinetics most effectively. With the high MB removal performance (higher than 95%) of the selected geopolymers, a new green and sustainable adsorbent could be introduced for wastewater depollution application.

Heterobimetallic three-dimensional 4d-4f coordination polymers based on 5-methyl-1-(pyridyn-4-ylmethyl)-1H-1,2,3-triazole-3,4-dicarboxylate

Three novel 4f-4d heterometallic coordination polymers (CPs), [Ln(H2O)3CdL2(NO3)]·6H2O (L ​= ​ethyl 5-methyl-1-(pyridin-4-ylmethyl)-1H-1,2,3-triazole-3,4-dicarboxylate; Ln ​= ​Eu, Gd, Tb 1, 2 and 3, respectively) have been successfully synthesized by hydrothermal treatment and slow cooling-down crystallization. These CPs have been structurally characterized by single-crystal X-ray diffraction. 1–3 are isostructural and consist of a three-dimensional network showing channels. The networks are reinforced via hydrogen bonds and π-π stacking interactions. The crystal topology analysis shows an infinite 2D layer topology with net symbol {4,4} (sql). The magnetic behavior of these compounds is explained by the expected contribution of almost isolated Ln (III) ions. An energy gap of 375 ​cm−1 between the 7F0 ground state and the first excited state of compound 1 has been deduced from magnetic data showing an excellent agreement with the spectroscopic data.

Microporous polymers based on triacetylarenes

Three-dimensional polymers are synthesized by polycondensation of triacetylarenes with the formation of 1,3,5-phentriyl and dimeric diphenylpropenone fragments. Microporous polyphenylenes with an intrinsic surface area of 650–690 m2 g–1 were obtained by additional heating at 450 °C. The values of the intrinsic surface area of polyphenylenes with rigid-chain rod-shaped inter-nodal fragments significantly exceed those of polyphenylenes with a flexible-chain inter-nodal fragments.

Cobalt Formate, a Functional MOF: Electrocatalytic Water Oxidation

Cobalt formate dihydrate, Co(HCOO)[Formula: see text]H2O (Co-MOF), a known crystalline substance, is a three-dimensional coordination polymer. The compound crystallizes in a monoclinic space group [Formula: see text]. In this work, we are reporting a unique synthesis method to prepare this MOF without using any formate salt or formic acid. The source of formate in compound Co-MOF is dimethylformamide (DMF) solvent used in the relevant synthesis. This metal–organic framework (MOF) containing compound, which can be described as a functional MOF, has recently been exploited for hydrogen isotope separation. This functional material has never been used as an electrocatalyst. In this work, we have demonstrated that this water insoluble compound Co-MOF can be used as heterogeneous electrocatalyst for oxygen evolution reaction (OER) by water oxidation at neutral pH. An overpotential of 275.5[Formula: see text]mV versus RHE was required to attain a current density of 1[Formula: see text]mAcm[Formula: see text]. The relevant Faradic efficiency (89.93%) and the turn over frequency (TOF) of 0.277[Formula: see text]s[Formula: see text] make the material an efficient electrocatalyst for water oxidation to molecular oxygen at neutral pH.

PRODUCTION OF BACTERIAL LIGNINOLYTIC ENZYMES AND THEIR POTENTIAL APPLICATION IN DECOLORIZATION OF DYES

Lignin is a complex, three-dimensional aromatic polymer, consisting of dimethoxylated, monomethoxylated and non-methoxylated phenylpropanoid subunits, and is recalcitrant in nature. In this study, the isolation of lignin degrading bacteria was carried out from decaying wood samples. Ligninolytic activity was evaluated by growing bacterial isolates on lignin monomers and by the degradation of indicator dyes. Out of 16, the bacterial isolates L8, L12, L13 and L15 exhibited growth on monomers viz., vanillin, veratryl alcohol, phenol, guaiacol and lignin, with efficient dye decolourization. Further, the production of ligninolytic enzymes (laccase, lignin peroxidase and manganese) was estimated for the 4 selected bacterial isolates. The maximum enzymatic activity response was noted in the case of isolate L15, with the best growth on every lignin monomer.

Enhancing the CO2-H2S corrosion resistance of oil well cement with a modified epoxy resin

The primary function of cement ring is to support and hang the casing, seal formation fluids and prevent interlayer channeling. However, in high-acid oil and gas fields, the cement ring is susceptible to corrosion by acidic media such as CO2 and H2S, which seriously shortens the production life of oil and gas wells and causes substantial economic losses. Therefore, it is very important to study the anti-corrosion performance of cement ring. Given the excellent bonding performance, high mechanical properties, and good corrosion resistance of epoxy resin, in this study, water-based modified epoxy resin was used as the anti-corrosion material to improve the anti-corrosion performance of oil well cement. The corrosion resistance of cement stone with modified epoxy resin was evaluated in acidic media in gas phase and liquid phase under simulated formation environment, and the corrosion resistance mechanism was analyzed. Studies have shown that the corrosion resistance of cement stone added with modified epoxy resin was significantly improved. After 30 days of corrosion in liquid and gas phase acidic medium, the strength loss rates were 9.8 % and 1.2 %, and the corrosion depths were 3.1 mm and 10.6 mm, respectively. Compared with cement stone without modified epoxy resin, the strength loss rates were as high as 32.1 % and 17.6 %, and the corrosion depths were 16.1 mm and 36.6 mm under the same corrosion conditions. SEM analysis shows that modified epoxy resin improves the corrosion resistance of cement stone mainly by filling pores to improve the compactness of cement stone structure and forming three-dimensional network polymer film to isolate acidic medium.

Light-induced synthesis and characterization of “Clickable” polyacrylamide hydrogels

Hydrogels are important three-dimensional network polymers for various technologies ranging from tissue engineering to bio-sensing due to their high water absorption, biocompatibility and non-toxic characteristics. A desirable feature of hydrogels is to possess suitable functionalities for post modification that can support their extended applications. In the present work, we report a facile synthesis of clickable polyacrylamide hydrogel by photopolymerization using acrylamide and propargyl acrylate in the presence of different photoinitiators and in the absence of any additional conventional crosslinking agent under ultraviolet (UV) and visible light. The effect of irradiation time on gel fraction, swelling degree and compressive elasticity was investigated. Thiol-ene, thiol-yne and copper-catalyzed azide-alkyne cycloaddition click functionality of the produced hydrogels were confirmed by using respective fluorescent click components.

3D-Printing-Assisted Extraluminal Anti-Reflux Diodes for Preventing Vesicoureteral Reflux through Double-J Stents.

This paper presents novel umbrella-shaped flexible devices to prevent vesicoureteral reflux along double-J stents, which is a backward flow of urine from the bladder to the kidney and is a critical issue in patients with urinary stones. The anti-reflux devices were designed to mechanically attach to the stent and were manufactured using three-dimensional (3D) printing and polymer casting methods. Based on the umbrella shapes, four different devices were manufactured, and the anti-reflux efficiency was demonstrated through in vitro experiments using a urination model. Consequently, penta-shaped devices exhibited the best anti-reflux performance (44% decrease in reflux compared to the stent without the device), and maximum efficiency occurred when the device was attached near the bladder-ureter junction. In addition, a disadvantage of 3D printing (i.e., unwanted rough surface) helped the device strongly adhere to the surface of the stent during the insertion operation. Finally, long-term soaking experiments revealed that the fabricated devices were mechanically robust and chemically stable (safe) even being soaked in urine for 4 weeks. The findings of this study support the use of additive manufacturing to make various flexible and biocompatible urological devices to mitigate critical issues in patients with urinary stones.

Novel three-dimensional coordination polymer of 2-(1,3,5-tri-aza-7-phospho-niatri-cyclo-[3.3.1.13,7]decan-7-yl)ethanoic acid with silver(I) tetra-fluoro-borate.

An AgI-based coordination polymer (CP), namely, poly[[[μ3-2-(1,3,5-tri-aza-7-phospho-niatri-cyclo-[3.3.1.13,7]decan-7-yl)ethano-ate-κ4 N:N':O,O']silver(I)] tetra-fluoro-borate], {[Ag(C9H16N3O2P)]BF4} n , was synthesized in an aqueous solution of zwitterionic 2-(1,3,5-tri-aza-7-phospho-niatri-cyclo-[3.3.1.13,7]decan-7-yl)ethan-o-ate (L) and AgBF4 with exclusion of light at room temperature. The colourless and light-insensitive CP crystallized in the monoclinic space group Cc. The asymmetric unit consists of an AgI cation, the zwitterionic L ligand and a BF4 - counter-ion. Each AgI ion is coordinated by two carboxyl-ate oxygen atoms in a chelating coordination mode, as well as one of the nitro-gen atoms of two neighbouring L ligands. The crystal structure of the CP was classified as a unique three-dimensional arrangement. The CP was also characterized in aqueous solutions by multinuclear NMR and HRMS spectroscopies and elemental analysis.

A new three-dimensional cadmium(II) coordination polymer based on bis[4-(2-methylimidazol-1-yl)phenyl]methanone: synthesis, structure and properties.

A novel three-dimensional CdII coordination polymer, namely, poly[[(μ3-benzene-1,4-diacetato)(μ2-benzene-1,4-diacetato)bis{μ2-bis[4-(2-methylimidazol-1-yl)phenyl]methanone}dicadmium(II)] tetartohydrate], {[Cd(C10H8O4)(C21H18N4O)]·0.25H2O}n or {[Cd(PBEA)(MIPMO)]·0.25H2O}n, (I), was synthesized by the hydrothermal method using benzene-1,4-diacetic acid (H2PBEA), bis[4-(2-methylimidazol-1-yl)phenyl]methanone (MIPMO) and Cd(NO3)2·6H2O. The title compound was structurally characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis, and exhibits a three-dimensional pillar-layer framework based on CdII-PBEA layers and MIPMO pillars, which can be simplified into a pcu topological network. The title compound displays a highly selective and sensitive sensing for Fe3+ ions in aqueous solution. In addition, it displays a high photocatalytic activity for the degradation of methylene blue (MB) in water under UV light irradiation.

Polymer interdigitated pillar electrostatic (PIPE) actuators

This work reports a three-dimensional polymer interdigitated pillar electrostatic actuator that can produce force densities 5–10× higher than those of biological muscles. The theory of operation, scaling, and stability is investigated using analytical and FEM models. The actuator consists of two high-density arrays of interdigitated pillars that work against a restoring force generated by an integrated flexure spring. The actuator architecture enables linear actuation with higher displacements and pull-in free actuation to prevent the in-use stiction associated with other electrostatic actuators. The pillars and springs are 3D printed together in the same structure. The pillars are coated with a gold–palladium alloy layer to form conductive electrodes. The space between the pillars is filled with liquid dielectrics for higher breakdown voltages and larger electrostatic forces due to the increase in the dielectric constant. We demonstrated a prototype actuator that produced a maximum work density of 54.6 µJ/cc and an electrical-to-mechanical energy coupling factor of 32% when actuated at 4000 V. The device was operated for more than 100,000 cycles with no degradation in displacements. The flexible polymer body was robust, allowing the actuator to operate even after high mechanical force impact, which was demonstrated by operation after drop tests. As it is scaled further, the reported actuator will enable soft and flexible muscle-like actuators that can be stacked in series and parallel to scale the resulting forces. This work paves the way for high-energy density actuators for microrobotic applications.

A three-dimensional gadolinium organic framework based on a pyridinedicarboxylic acid organic linker with a paddle-wheel-type network structure.

A new gadolinium(III)-pyridine-2,5-dicarboxylic acid (GdIII-2,5-H2pdc)-based three-dimensional coordination polymer, namely, poly[dimethylazanium [bis(μ-pyridine-2,5-dicarboxylato)gadolinium(III)]], {[(CH3)2NH2][Gd(C7H3NO4)2]}n, CP-1, has been synthesized via a typical solvothermal method. The as-synthesized material was characterized in the solid state using single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis and FT-IR spectroscopy. During the synthesis of CP-1, the in situ dimethylformamide (DMF) promotes the formation of a dimeric unit and these act as secondary building blocks in the assembly of a three-dimensional anionic {[Gd(pdc)2]-}∞ framework. The framework has channels along the c axis which are filled by dimethylazanium cations. Interestingly, the framework shows a helical-type assembly running down the a axis. A Hirshfeld surface analysis of CP-1 suggests that extra stability is provided by hydrogen-bonding interactions. The magnetic properties of CP-1 showed weak antiferromagnetic couplings between adjacent Gd3+ ions.

An Attempt to Optimize Supercritical CO2 Polyaniline-Polycaprolactone Foaming Processes to Produce Tissue Engineering Scaffolds.

Conjugated polymers are biomaterials with high conductivity characteristics because of their molecular composition. However, they are too rigid and brittle for medical applications and therefore need to be combined with non-conductive polymers to overcome or lessen these drawbacks. This work has, consequently, focused on the development of three-dimensional scaffolds where conductive and non-conductive polymers have been produced by combining polycaprolactone (PCL) and polyaniline (PANI) by means of supercritical CO2 foaming techniques. To evaluate their therapeutic potential as implants, a series of experiments have been designed to determine the most influential variables in the production of the three-dimensional scaffolds, including temperature, pressure, polymer ratio and depressurization rate. Internal morphology, porosity, expansion factor, PANI loads, biodegradability, mechanical and electrical properties have been taken as the response variables. The results revealed a strong influence from all the input variables studied, as well as from their interactions. The best operating conditions tested were 70 °C, 100 bar, a ratio of 5:1 (PCL:PANI), a depressurization rate of 20 bar/min and a contact time of 1 h.

Pillar[5]arene-Integrated Three-Dimensional Framework Polymers for Macrocycle-Induced Size-Selective Catalysis.

Size-selective catalysis is of key importance in the conversion of crude oil or biomass. Here, we fabricate three pillar[5]arene-integrated porous organic polymers with three-dimensional (3D) network structures using 3D cross-linkers. The resulting polymers possess a high surface-to-mass ratio and exhibit exceptional size-selective catalysis in Knoevenagel condensation reactions. In addition, a mechanistic study indicates that the size-selective catalysis is due to the host-guest interaction between pillar[5]arene and substrates. This study suggests that macrocycle-containing polymers could be a promising candidate for size-selective catalysis.

Crystal structure of a three-dimensional neodymium(III) coordination polymer, [Nd2(H2O)6(glutarato)(SO4)2] n.

A three-dimensional coordination polymer, poly[hexa-aqua-(μ4-glutarato)bis(μ3-sulfato)-dineodymium(III)], [Nd2(glutarato)(SO4)2(H2O)6] n (glutarato2- = C5H6O4 2-), 1, consisting of cationic {Nd2(H2O)6(SO4)2} n 2n+ layers linked by bridging glutarate ligands, was synthesized by the microwave-heating technique within few minutes. The crystal structure of 1 consists of two crystallographically independent TPRS-{NdIIIO9} (TPRS is tricapped trigonal-prismatic geometry) units that form an edge-sharing dinuclear cluster inter-connected to neighbouring dimers by the μ3-SO4 2- anions, yielding a cationic two-dimensional {Nd2(H2O)6(SO4)2} n 2n+ sheet. Adjacent cationic layers are then linked via the μ4-glutarato2- ligands into a three-dimensional coordination network. Strong O-H⋯O hydrogen bonds are the predominant inter-action in the crystal structure.

Postsynthetic Defect Formation in Three-Dimensional Hofmann-Type Coordination Polymers and Its Impact on Catalytic Activity.

We report a systematic investigation of postsynthetic defect formation in Hofmann-type coordination polymers M(pz)[M'(CN)4] (M = Fe2+, Co2+, Ni2+; M' = Pd2+, Pt2+; pz = pyrazine). These compounds readily undergo selective ligand exchange at the pyrazine site when immersed in methanol (MeOH) at ambient temperature. The ligand exchange changes the chemical formula to M(pz)1-x(MeOH)2x[M'(CN)4] (0 < x < 0.3), affording a defective coordination environment around the M ions. The defect concentration is highly dependent on the combination of the metal ions and solvent species, reaching the defect concentration of ca. 30% (x ∼ 0.3) at maximum. The magnetic state of one such coordination polymer gives an additional control of the defect formation, making the compound less susceptible to the ligand exchange at the low-spin state. Structures that form the defects at a high concentration function as catalysts and promote an acetalization reaction heterogeneously by providing Lewis acidic sites. The solvent-dependent character of the defect formation can be used to control the catalytic activity of the active compounds, demonstrating a facile defect engineering for functionalizing solid materials.

Synthesis, crystal structure, and luminescence properties of a three-dimensional coordination polymer from europium(iii) carbonate hemioxalate hydrate

A new luminescent lanthanide coordination polymer composed of europium(iii), oxalate and carbonate was prepared.

Reversible Topochemical Polymerization and Depolymerization of a Crystalline Three-Dimensional Porous Organic Polymer With C–C Bond Linkages

Reversible Topochemical Polymerization and Depolymerization of a Crystalline Three-Dimensional Porous Organic Polymer With C–C Bond Linkages