3D printing encouraging desired in-situ polypyrrole seed-polymerization for ultra-high energy density supercapacitors

The tireless pursuit of supercapacitors with high energy density entails the parallel advancement of wellsuited electrode materials and elaborately engineered architectures.Polypyrrole(PPy)emerges as an exceedingly conductive polymer and a prospective pseudocapacitive materials for supercapacitors,yet the inferior cyclic stability and unpredictable polymerization patterns severely impede its real-world applicability.Here,for the first time,an innovative seed-induced in-situ polymerization assisted 3D printing strategy is proposed to fabricate PPy-reduced graphene oxide/poly(vinylidene difluoride-cohexafluoropropylene)(PVDF-HFP)(PPy-rGO/PH)electrodes with controllable polymerization behavior and exceptional areal mass loading.The preferred active sites uniformly pre-planted on the 3D-printed graphene substrates serve as reliable seeds to induce efficient polypyrrole deposition,achieving an impressive mass loading of 185.6 mg cm^(-2)(particularly 79.2 mg cm^(-2)for polypyrrole)and a superior areal capacitance of 25.2 F cm^(-2)at 2 mA cm^(-2)for a 12-layer electrode.In agreement with theses appealing features,an unprecedented areal energy density of 1.47 mW h cm^(-2)for a symmetrical device is registered,a rarely achieved value for other PPy/rGO-based supercapacitors.This work highlights a promising route to preparing high energy density energy storage modules for real-world applications.

Effect of solvent on the initiation mechanism of living anionic polymerization of styrene:A computational study

For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and kinetics.In this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory(DFT)calculations and kinetic modeling.In terms of mechanism,it is found that the stronger the solvent polarity,the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent molecules.Furthermore,we also found that the stronger the solvent polarity,the higher the monomer initiation energy barrier and the smaller the initiation rate coefficient.Counterintuitively,initiation is more favorable at lower temperatures based on the calculated results ofΔG_(TS).Finally,the kinetic characteristics in different solvents were further examined by kinetic modeling.It is found that in benzene and n-pentane,the polymerization rate exhibits first-order kinetics.While,slow initiation and fast propagation were observed in tetrahydrofuran(THF)due to the slow free ion formation rate,leading to a deviation from first-order kinetics.

Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed Ethylene Chain-Walking Polymerization

The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature.

Synthesis and Characterization of Poly Styrene-Co-Poly 2-Hydroxyethylmethacrylate (HEMA) Copolymer and an Investigation of Free-Radical Copolymerization Propagation Kinetics by Solvent Effects

A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The samples obtained from the synthesis were characterized by Fourier Transform-Infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The results show that the synthesis of the polymers is more feasible under neat conditions rather than solvent directed reaction. Moreover, the DSC data shows that the polystyrene obtained is amorphous in nature and therefore displayed only a glass transition signal rather than crystallization and melting peaks. In addition, this study indicates that homolopolymerization of styrene via free radical polymerization tends to be preferable in less polar solvents like THF than in non-polar solvents like benzene. Benzene might destabilize the formation of the reactive radicals leading to the formation of the products. In summary, the homolpolymerization of styrene is more feasible than the homopolymerization 2-hydroxyethyl methacrylate under the experimental setup used. Styrene is more reactive than 2-hydroxyethyl methacrylate than free radical polymerization reaction due in part of the generation of the benzylic radical intermediate which is more stable leading to the formation of products than alkyl radical which are less stable. Furthermore, polymerization of styrene under neat conditions is preferable in solvent-assisted environments. The choice of solvent for the synthesis of these polymers is crucial and therefore the selection of solvent that leads to the formation of a more stable reaction intermediate is more favorable. It is worth noting that the structure of the proposed copolymer consists of a highly polar and hydrophilic monomer, 2-hydroxyethyl methacrylate and a highly non-polar and hydrophobic monomer, styrene. These functionalities constitute an amphiphilic copolymer with diverse characteristics. A plausible explanation underlying our observations is that the reaction conditions employed in the synthesis of these copolymers might not be the right route required under free radical polymerization.

Mathematical Model and Advanced Control for Gas-phase Olefin Polymerization in Fluidized-bed Catalytic Reactors

在这研究，在为煤气阶段的催化石蜡聚合建模的开发用 Ziegler-Natta 催化剂的使流体化床的反应堆(FBR ) 被介绍。在乳剂阶段说明在稳固的粒子和包围气体之间的质量和传热的修改数学模型在这个工作被开发包括地点激活反应。在现在的学习开发的这个模型是随后与著名模型相比，也就是水泡生长，混合得好并且为多孔、非多孔的催化剂的模子常数水泡尺寸模型。我们从模型获得了的结果离经常的水泡尺寸模型很靠近，在反应的开始的混合得好的模型和水泡生长模型但是它的全面行为变化了并且在半工作时间以后与水泡生长模型和经常的水泡尺寸模型相比接近混合得好的模型。神经网络的基于的预兆的控制器被实现控制系统，给可接受的结果并且与常规 PID 控制器相比。

Triggering dynamics of acetylene topochemical polymerization

Topochemical reactions are a promising method to obtain crystalline polymeric materials with distance-determined regio-or stereoselectivity.It has been concluded on an empirical basis that the closest intermolecular C⋅⋅⋅C distance in crystals of alkynes,d(C⋅⋅⋅C)min,should reach a threshold of∼3Åfor bonding to occur at room temperature.To understand this empirical threshold,we study here the polymerization of acetylene in the crystalline state under high pressure by calculating the structural geometry,vibrational modes,and reaction profile.We find d(C⋅⋅⋅C)min to be the sum of an intrinsic threshold of 2.3Åand a thermal displacement of 0.8Å(at room temperature).Molecules at the empirical threshold move via several phonon modes to reach the intrinsic threshold,at which the intermolecular electronic interaction is sharply enhanced and bonding commences.A distance–vibration-based reaction picture is thus demonstrated,which provides a basis for the prediction and design of topochemical reactions,as well as an enhanced understanding of the bonding process in solids.

In Situ Directional Polymerization of Poly(1,3-dioxolane)Solid Electrolyte Induced by Cellulose Paper-Based Composite Separator for Lithium Metal Batteries

In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,which employs alumina as the inorganic reinforcing material and is loaded with polymerization initiator aluminum trifluoromethanesulfonate.Based upon this,a separator-induced in situ directional polymerization technique is demonstrated,and the extra addition of initiators into liquid precursors is no longer required.The polymerization starts from the surface and interior of the separator and extends outward with the gradually dissolving of initiators into the precursor.Compared with its traditional counterpart,the separator-induced poly(1,3-dioxolane)electrolyte shows improved interfacial contact as well as appropriately mitigated polymerization rate,which are conducive to practical applications.Electrochemical measurement results show that the prepared poly(1,3-dioxolane)solid electrolyte possesses an oxidation potential up to 4.4 V and a high Li+transference number of 0.72.After 1000 cycles at 2 C rate(340 mA g^(−1)),the assembled Li||LiFePO_(4)solid battery possesses a 106.8 mAh g^(−1)discharge capacity retention and 83.5%capacity retention ratio,with high average Coulombic efficiency of 99.5%achieved.Our work may provide new ideas for the design and application of in situ polymerization technique for solid electrolytes and solid batteries.

Mechanistically Novel Frontal-Inspired In Situ Photopolymerization:An Efficient Electrode|Electrolyte Interface Engineering Method for High Energy Lithium Metal Polymer Batteries

The solvent-free in situ polymerization technique has the potential to tailor-make conformal interfaces that are essential for developing durable and safe lithium metal polymer batteries(LMPBs).Hence,much attention has been given to the eco-friendly and rapid ultraviolet(UV)-induced in situ photopolymerization process to prepare solid-state polymer electrolytes.In this respect,an innovative method is proposed here to overcome the challenges of UV-induced photopolymerization(UV-curing)in the zones where UV-light cannot penetrate,especially in LMPBs where thick electrodes are used.The proposed frontal-inspired photopolymerization(FIPP)process is a diverged frontal-based technique that uses two classes(dual)of initiators to improve the slow reaction kinetics of allyl-based monomers/oligomers by at least 50%compared with the conventional UV-curing process.The possible reaction mechanism occurring in FIPP is demonstrated using density functional theory calculations and spectroscopic investigations.Indeed,the initiation mechanism identified for the FIPP relies on a photochemical pathway rather than an exothermic propagating front forms during the UV-irradiation step as the case with the classical frontal photopolymerization technique.Besides,the FIPP-based in situ cell fabrication using dual initiators is advantageous over both the sandwich cell assembly and conventional in situ photopolymerization in overcoming the limitations of mass transport and active material utilization in high energy and high power LMPBs that use thick electrodes.Furthermore,the LMPB cells fabricated using the in situ-FIPP process with high mass loading LiFePO_(4)electrodes(5.2 mg cm^(-2))demonstrate higher rate capability,and a 50%increase in specific capacity against a sandwich cell encouraging the use of this innovative process in large-scale solid-state battery production.

Scale-up and thermal stability analysis of fluidized bed reactors for ethylene polymerization

A set of hydrodynamic similarity laws is applied to the scale-up of ethylene polymerization fluidized bed reactors(FBRs)under the condensed mode operation.The thermal stability of open-loop controlled FBRs is investigated by the homotopy continuation method.And the Hopf bifurcation point is selected as an index of the thermal stability similarity.The simulation results show the similarity in state variables,operation parameters,the space-time yield(STY),and the thermal stability of FBRs with different scales.Furthermore,the thermal stability behaviors and similarity of the closed-loop controlled FBRs with different scales are analyzed.The observed similar trend of Hopf bifurcation curves reveals the similarity in the thermal stability of closed-loop controlled FBRs with different scaling ratios.In general,the results of the thermal stability similarity confirm that the hydrodynamics scaling laws proposed in the work are applicable to the scale-up of FBRs under the condensed mode operation.

Preparation of Poly-α-Olefin Microcapsule Particles Coated with Polyurethane as a Drag Reducer Based on Interface Polymerization

The molecular behavior of polyurethane(PU)coating materials during the surface adsorption of poly-α-olefin as a drag reducing polymer was explored by a molecular dynamics simulation.Three different PU capsule wall materials were synthesized using two reaction monomers,and a poly-α-olefin/PU drag reducer microcapsule was prepared based on interface polymerization.The structure,morphology,thermal stability,compressive strength,and drag reduction performance of the microcapsules were characterized and compared.The results showed that a non-bonding interaction induced the adsorption of the PU coating material,poly-α-olefin and PU then fused at the interface,and the PU coating material was embedded into the inner grooves of poly-α-olefin in the form of a local mosaic,thereby forming a stable core–shell structure.The morphological characterization indicated that PU and poly-α-olefin could form microcapsule structures.The thermal decomposition temperature of the microcapsule was dependent on the type of capsule wall material.The microcapsule structure had a slight effect on poly-α-olefin drag reduction.The system enabled poly-α-olefin to exist in powdered particles through microcapsulation,and had a good dispersion effect that facilitated storage and transport processes.The method effectively inhibited the accumulation and bonding of poly-α-olefin at room temperature.

Apparent Kinetics of 1-Decene Polymerization Catalyzed Using the Ionic Liquid[Bmim]_(x)[C_(2)H_(5)NH_(3)]_(1-x)[Al_(2)Cl_(7)]

Poly-α-olefin(PAO)synthetic oil,a regular long-chain alkane produced from the catalytic polymerization ofα-olefin,is a high-quality lubricating base oil with huge market potential.In this study,PAO synthesis based on the catalytic polymerization of 1-decene using the ionic liquid(IL)[Bmim]_(x)[C_(2)H_(5)NH_(3)]_(1-x)[Al_(2)Cl_(7)]as the catalyst was studied.Compared with the conventional catalyst[Bmim][Al_(2)Cl_(7)],the obtained PAO product incorporates more trimers and tetramers of 1-decene and contains few double-bond end groups,demonstrating a better catalytic system for PAO-10 production.The apparent polymerization kinetics of 1-decene in this catalytic system were studied based on the 1-decene concentration,catalyst concentration,and reaction temperature.An apparent kinetic equation for PAO formation was determined,providing a promising strategy for PAO production using 1-decene polymerization.

Pore throat structure heterogeneity and its effect on gas-phase seepage capacity in tight sandstone reservoirs:A case study from the Triassic Yanchang Formation,Ordos Basin

The microscopic heterogeneity of pore-throat structures in tight sandstone is a crucial parameter for understanding the transport mechanism of fluid flow.In this work,we firstly developed the new procedure to characterize the pore size distribution(PSD)and throat size distribution(TSD)by combining the nuclear magnetic resonance(NMR),cast thin section(CTS),and constant-rate mercury injection(CRMI)tests,and used the permeability estimated model to verify the full-scale PSD and TSD.Then,we respectively analyzed the fractal feature of the pore and throat,and characterized the heterogeneity of pores and throats.Finally,we elaborated the effect of the pore and throat heterogeneity on the gas-phase seepage capacity base on the analysis of the simple capillary tube model and gas-flooding experiment.The results showed that(1)The PSD and TSD of the tight sandstone sample ranged from 0.01 to 10 mm and from 0.1 to 57 mm,respectively,mainly contributed by the micropores and mesopores.Meanwhile,the permeability estimated by the PSD and TSD was consistent with the experimental permeability,and relative error was lower than 8%.(2)The PSD and TSD exhibited multifractal characteristics,and singularity strength range,Δα,could be used as the indicator for characterizing the heterogeneity of pore and throat.Furthermore,the throat of the sample showed stronger heterogeneity than that the pore.(3)The throats played an important role for the fluid transport in the tight sandstone,and the effect of the throat heterogeneity on the gas-phase seepage capacity was different under the lower and higher injection pressure.The macropores and micropores maybe respectively become the preferential migration pathways at the lower and higher injection pressure.In the end,the identification plate was established in our paper,and could be described the relationship among the throat heterogeneity,injection pressure,permeability and flow path of the gas phase in the tight sandstone.

In-situ polymerized PEO-based solid electrolytes contribute better Li metal batteries:Challenges,strategies,and perspectives

Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.

Comprehension-driven design of advanced multi-block single-ion conducting polymer electrolytes for high-performance lithium-metal batteries

The continuously growing importance of batteries for powering(hybrid)electric vehicles and storing renewable energy has prompted a renewed focus on lithium-metal batteries(LMBs)in recent years,as its high theoretical specific capacity of about 3860 mA h g^(-1) and very low redox potential(-3.04 V vs.the standard hydrogen electrode)promise substantially higher energy densities compared to current lithium-ion batteries(LIBs)[1].However,lithium metal electrodes face severe challenges associated with the risk of dendritic lithium deposition and the high reactivity with traditional organic liquid electrolytes,resulting in a continuous loss of electrochemically active lithium and a relatively low Coulombic efficiency[2].To address these challenges,solid inorganic and polymer electrolytes have emerged as a potentially saferalternative.

Effect of electron-electron interaction on polarization process of exciton and biexciton in conjugated polymer

By using one-dimensional tight-binding model modified to include electron-electric field interaction and electron-electron interaction,we theoretically explore the polarization process of exciton and biexciton in cis-polyacetylene.The dynamical simulation is performed by adopting the non-adiabatic evolution approach.The results show that under the effect of moderate electric field,when the strength of electron-electron interaction is weak,the singlet exciton is stable but its polarization presents obvious oscillation.With the enhancement of interaction,it is dissociated into polaron pairs,the spin-flip of which can be observed through modulating the interaction strength.For the triplet exciton,the strong electron-electron interaction restrains its normal polarization,but it is still stable.In the case of biexciton,the strong electron-electron interaction not only dissociate it,but also flip its charge distribution.The yield of the possible states formed after the dissociation of exciton and biexciton is also calculated.

Influence of Mass Ratio of Resin and Stabilizer on Mechanical Properties of Mo Fiber-reinforced Granite Polymer Composite

Because inferior mechanical strength of granite polymer composite(GPC)has become the main drawback limiting its application and popularization,Mo fibers were added into(GPC)to improve its mechanical strength.Mechanical properties of matrix materials with different mass ratio of resin and stabilizer(MRRS)were investigated systematically.The influences of MRRS on interface bonding strength of Mo fiber-matrix,wettability and mechanical strength of GPC were discussed,respectively,and the theoretical calculation result of MRRS k was obtained,with the optimal value of k=4.When k=4,tensile strength,tensile strain and fracture stress of the cured resin achieve the maximum values.But for k=7,the corresponding values reach the minimum.With the increase of MRRS k,surface free energy of the cured resin first increases and then decreases,while contact angles between Mo sample and matrix have displayed the opposite trend.Wettability of resin to Mo fiber is the best at k=4.Pulling load of Mo fiber and interface bonding strength appear the maximum at k=4,followed by k=5,k=3 the third,and k=7 the minimum.When k=4,mechanical properties of Mo fiber-reinforced GPC are optimal,which is consistent with the result of theoretical calculation.This study is of great significance to get better component formulas of Mo fiber reinforced GPC and to improve its application in machine tools.

A Stable Open-Shell Conjugated Diradical Polymer with Ultra-High Photothermal Conversion Efficiency for NIR-Ⅱ Photo-Immunotherapy of Metastatic Tumor

Massive efforts have been concentrated on the advance of eminent near-infrared(NIR) photothermal materials(PTMs) in the NIR-Ⅱ window(1000–1700 nm), especially organic PTMs because of their intrinsic biological safety compared with inorganic PTMs. However, so far, only a few NIR-Ⅱresponsive organic PTMs was explored, and their photothermal conversion efficiencies(PCEs) still remain relatively low. Herein, donor–acceptor conjugated diradical polymers with open-shell characteristics are explored for synergistically photothermal immunotherapy of metastatic tumors in the NIR-Ⅱ window. By employing side-chain regulation, the conjugated diradical polymer TTB-2 with obvious NIR-Ⅱ absorption was developed, and its nanoparticles realize a record-breaking PCE of 87.7% upon NIR-Ⅱ light illustration. In vitro and in vivo experiments demonstrate that TTB-2 nanoparticles show good tumor photoablation with navigation of photoacoustic imaging in the NIR-Ⅱ window, without any side-effect. Moreover, by combining with PD-1 antibody,the pulmonary metastasis of breast cancer is high-effectively prevented by the efficient photo-immunity effect. Thus, this study explores superior PTMs for cancer metastasis theranostics in the NIR-Ⅱ window, offering a new horizon in developing radical-characteristic NIR-Ⅱ photothermal materials.

Erosion control of Chinese loess using polymer SH and ryegrass

The China Loess Plateau is subjected to severe soil erosion triggered by intense rainfall,resulting in significant harm and losses to both human society and the natural surroundings.In this study,a novel technique for managing loess erosion is introduced,which involves the utilization of a combined polymer SH and ryegrass.A comprehensive series of tests were undertaken,including rainfall erosion tests,disintegration experiments,and scanning electron microscopy examinations,to assess the accumulative sediment yield(ASY),disintegration ratio,and microstructural features of both untreated and treated loess samples.The results showed a significant reduction in ASY with increased dry density of untreated loess.Furthermore,the combined technique effectively controlled erosion,limiting ASY to 266.2 g/cm^(2)in 60 minutes.This was approximately one-sixth,one-ninth,and one-fifteenth of the ASY in SH-treated loess(L-SH),ryegrass-treated loess(L-R),and untreated loess,respectively.It resisted disintegration better than ryegrass alone but slightly less than SH.This improvement was due to the combined effect of SH and ryegrass,which reduced raindrop impact,improved loess microstructure,and boosted ryegrass growth.The innovative technique holds the potential to be applied as a field-scale technique in the Loess Plateau region of China.

Highly Elastic,Bioresorbable Polymeric Materials for Stretchable,Transient Electronic Systems

Substrates or encapsulants in soft and stretchable formats are key components for transient,bioresorbable electronic systems;however,elastomeric polymers with desired mechanical and biochemical properties are very limited compared to nontransient counterparts.Here,we introduce a bioresorbable elastomer,poly(glycolide-co-ε-caprolactone)(PGCL),that contains excellent material properties including high elongation-at-break(<1300%),resilience and toughness,and tunable dissolution behaviors.Exploitation of PGCLs as polymer matrices,in combination with conducing polymers,yields stretchable,conductive composites for degradable interconnects,sensors,and actuators,which can reliably function under external strains.Integration of device components with wireless modules demonstrates elastic,transient electronic suture system with on-demand drug delivery for rapid recovery of postsurgical wounds in soft,time-dynamic tissues.

Polymer engineering for electrodes of aqueous zinc ion batteries

With the increasing demand for scalable and cost-effective electrochemical energy storage,aqueous zinc ion batteries(AZIBs)have a broad application prospect as an inexpensive,efficient,and naturally secure energy storage device.However,the limitations suffered by AZIBs,including volume expansion and active materials dissolution of the cathode,electrochemical corrosion,irreversible side reactions,zinc dendrites of the anode,have seriously decelerated the civilianization process of AZIBs.Currently,polymers have tremendous superiority for application in AZIBs attributed to their exceptional chemical stability,tunable structure,high energy density and outstanding mechanical properties.Considering the expanding applications of AZIBs and the superiority of polymers,this comprehensive paper meticulously reviews the benefits of utilizing polymeric applied to cathodes and anodes,respectively.To begin with,with adjustable structure as an entry point,the correlation between polymer structure and the function of energy storage as well as optimization is deeply investigated in respect to the mechanism.Then,depending on the diversity of properties and structures,the development of polymers in AZIBs is summarized,including conductive polymers,redox polymers as well as carbon composite polymers for cathode and polyvinylidene fluoride-,carbonyl-,amino-,nitrile-based polymers for anode,and a comprehensive evaluation of the shortcomings of these strategies is provided.Finally,an outlook highlights some of the challenges posed by the application of polymers and offers insights into the potential future direction of polymers in AZIBs.It is designed to provide a thorough reference for researchers and developers working on polymer for AZIBs.