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Objective: Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD). Hungry bone syndrome (HBS) after parathyroidectomy (PTX) is a serious complication, which can lead to diarrhea, convulsion, arrhythmia and even death. This study was aimed to determine the risk factors for HBS after PTX in dialysis patients with SHPT and construct a nomogram prediction model to predict the incidence of postoperative complications. Methods: Clinical data were collected from 80 maintenance hemodialysis (MHD) patients with SHPT who received total PTX in the Second Hospital of Jilin University from January 2018 to September 2021. In line with the inclusion and exclusion criteria, totally 75 patients were finally enrolled for analysis. Patients were divided into two groups for retrospective analysis according to the severity of postoperative HBS, including HBS group and non-HBS (N-HBS) group. Univariate and multivariate logistic regression analyses were conducted to determine the risk factors for postoperative HBS. Afterwards, the receiver operating characteristic (ROC) curves were plotted based on the statistical analysis results, aiming to compare the prediction effects of different predicting factors. Finally, the nomogram was established to evaluate the occurrence probability of postoperative complications predicted by the risk factors. Results: Among the 75 patients, 32 had HBS (HBS group), while 43 did not have HBS (N-HBS group). Univariate analysis results indicated that, the preoperative intact parathyroid hormone (iPTH) and serum alkaline phosphatase (ALP) levels in HBS group were significantly higher than those in N-HBS group, while preoperative hemoglobin and preoperative albumin (Alb) levels were significantly lower than those in N-HBS group. As discovered by multivariate logistic regression analysis, preoperative iPTH (OR = 1.111, P= 0.029) and ALP (OR = 1.010, P< 0.001) were the independent risk factors for postoperative HBS. ROC curve analysis suggested that the area under the curve (AUC) values of these two indicators were 0.873 and 0.926, respectively (P< 0.0001). Subsequently, the nomogram model for predicting HBS was constructed. The model verification results indicated that the predicted values were basically consistent with the measured values, with the C-index of 0.943 (95% CI 0.892–0.994). Besides, the calibration curve was consistent with the ideal curve, demonstrating the favorable accuracy and discrimination of the model. Conclusions: Preoperative iPTH and preoperative ALP are the risk factors for postoperative HBS, which can be used to guide the early clinical intervention.

Background: Elabela, a recently discovered hormonal peptide containing 32 amino acids, is a ligand for the apelin receptor. It can lower blood pressure and attenuate renal fibrosis. However, the clinicopathological relationship between Elabela level and renal damage caused by benign hypertension (BHT) and malignant hypertension (MHT) has not been elucidated. Therefore, we investigated the clinicopathological correlation between serum Elabela level and renal damage caused by BHT and MHT. Methods: The participants comprised 50 patients and 25 age-matched healthy adults. The 50 patients were separated into two groups: MHT (n= 25) and BHT groups (n= 25). We analyzed their medical histories, demographics, and clinical examinations, including physical and laboratory tests. Results: The results showed that serum Elabela level decreased gradually with a continuous increase in blood pressure from the healthy control group, BHT, to MHT. Moreover, Elabela levels negatively correlated with BMI (R=  − 0.27, P= 0.02), SBP (r=  − 0.64, P< 0.01), DBP (r=  − 0.58, P< 0.01), uric acid (r=  − 0.39, P< 0.01), bun (r=  − 0.53, P< 0.01), and Scr (r=  − 0.53 P< 0.01) but positively correlated with eGFR (r= 0.54, P< 0.01). Stepwise multivariate linear regression analysis showed that SBP was the variable most related to Elabela (t=  − 5.592, P< 0.01). Conclusions: Serum Elabela levels decreased in patients with hypertension, especially malignant hypertension, and has the potential to be a marker of hypertension-related kidney damage.

Background: There are arguments for individualized treatments and the necessity of non-invasive biomarkers for patients with IgA nephropathy (IgAN) according to gender, but the rationale remains unclear. We aimed to investigate the relationship between urine exosomal circular RNA (circRNA) levels, related genes, clinical features, and renal pathological features in IgA nephropathy patients of different genders. Methods: Clinicopathological data from patients of different genders from a multicenter cohort were retrospectively analyzed. We used the Oxford classification to examine the severity of pathological damage in these patients. We compared clinical features and renal pathologies between IgAN patients of different genders. Using findings of urine exosomal circRNAs from male IgAN patients, we analyzed the relationship between this factor, the regulated genes located on the sex chromosomes, and renal pathologies. Results: A total of 502 IgAN patients were included. The proportion of male patients with crescent formation was higher than that of females (p= 0.019). Multivariate logistic regression analysis showed that proteinuria was an independent marker for crescent formation in male and female patients with IgAN, while smoking and higher low-density lipoprotein cholesterol (LDL-C) levels were independent risk factors for crescent formation in males alone. Urine exosomal circRNA chrY:15478147-15481229- located on the Y chromosome in male patients was negatively correlated with the expressions of UTY in specific regions of the Y chromosome. Conclusion: Compared with female patients, males with IgAN had more severe renal dysfunction and a higher probability of glomerular crescent formation. Urine exosomal circRNA chrY:15478147-15481229- might participate in the pathogenesis of IgAN in male patients by altering UTY expressions. Graphic abstract:

Membrane-less scenarios that involve liquid–liquid phase separation (coacervation) provide clues for how protocells might emerge. Here, we report a versatile approach to construct coacervates by mixing fatty acid with biomolecule dopamine as the protocell model. The coacervate droplets are easily formed over a wide range of concentrations. The solutes with different interaction characteristics, including cationic, anionic, and hydrophobic dyes, can be well concentrated within the coacervates. In addition, reversible self-assemblies of the coacervates can be controlled by concentration, pH, temperature, salinity, and bioreaction realizing cycles between compartmentalization and noncompartmentalization. Through in situdopamine polymerization, the stability of coacervate droplets is significantly improved, leading to higher resistance toward external factors. Therefore, the coacervates based on fatty acid and dopamine could serve as a bottom-up membrane-less protocell model that provides the links between the simple (small molecule) and complex (macromolecule) systems in the process of cell evolution.

Metal nanofibers with excellent electrical conductivity and superior mechanical flexibility have great potentials for fabrication of lightweight, flexible, and high-performance electromagnetic interference (EMI) shielding architectures. The weak interactions and large contact resistance among the wires, however, hinder their assembly into robust and high-performance EMI shielding monoliths. In this work, we used low fractions of polymers to assist the construction of lightweight, flexible, and highly conductive silver nanowire (AgNW) cellular monoliths with significantly enhanced mechanical strength and EMI shielding effectiveness (SE). The normalized surface specific SE of our AgNW-based cellular monoliths can reach up to 20522 dB·cm2/g, outracing that of most shielding materials ever reported. Moreover, this robust conductive framework enabled the successful fabrication of hydrophobic, ultraflexible, and highly stretchable aerogel/polymer composites with outstanding EMI SE even at an extremely low AgNW content. Thus, this work demonstrated a facile and efficient strategy for assembling metal nanofiber-based functional high-performance EMI shielding architectures.

Metal–organic frameworks (MOFs), known for their tailorable porous structures and large specific surface areas, are appealing for electrochromic applications as their abundant pores may greatly benefit the charge transport required for electrochromic switching. Herein, for the first time, a simple, scalable, and cost-effective electrochemical deposition method for fabrication of high-performance and durable MOFs-based electrochromic films with redox-active ligands was developed. The fabricated film can achieve rapid switching speed (both coloration and bleaching time <5 s) because the inherent cavities of the MOFs greatly facilitate ion insertion and extraction. In addition, the film constructed with optimized parameters shows a high optical contrast of 65%@700 nm and can be stably switched for 1000 cycles with <5% contrast attenuation, which is by far the best cycling performance for MOFs-based electrochromic materials ever reported. Furthermore, our method enables the scalable preparation of large-area MOFs-based electrochromic thin films without using large high-pressure reaction vessels, and the as-prepared film in this work could be switched well between colored and bleached states. This new method, therefore, opens up a new avenue to broaden the use of MOFs-based thin films for electrochromic applications.

In this Article, we report the layer-by-layer (LbL) assembly and electrochromic properties of polyaniline-tethered cubic polyhedral oligomeric silsesquioxane (POSS-PANI)/sulfonated polyaniline (SPANI) multilayer thin films. The interaction between POSS-PANI and SPANI is characterized using X-ray photoelectron spectroscopy (XPS), ultraviolet−visible-near-infrared spectroscopy, and four-point probe conductivity. We show that the inclusion of SPANI during LbL assembly effectively dopes the underlying POSS-PANI layer and extends the conjugation length, as evidenced by probing the surface layers with XPS. We also demonstrate that the POSS-PANI/SPANI multilayer films have more electroactive units, lower band gap energies, and higher electrical conductivity values compared to those of POSS-PANI/poly(2-acrylamido-methane-2-propanesulfonic acid) (PAMPS) and spin-coated SPANI films. Under constant applied potentials, a 50 bilayer film of POSS-PANI/SPANI, (POSS-PANI/SPANI)50, shows significant enhancement in optical contrast compared with (POSS-PANI/PAMPS)50. Furthermore, the switching kinetics of (POSS-PANI/SPANI)50are much faster than that of the spin-coated SPANI. The improvement in electrochromic contrast under dynamic switching conditions is attributed to the presence of a larger number of electrochromic units in POSS-PANI/SPANI, the loose packing structure of POSS-PANI brought by its starlike molecular architecture, and the unique morphology created by the LbL assembly.

IgA nephropathy (IgAN) is the most common primary glomerular disease in the world, and up to 40% of patients with IgAN develop end-stage renal disease (ESRD). At present, an increasing amount of evidence indicates that the pathogenesis of IgAN is related to autoimmunity. In recent years, several studies have shown that B cell activating factors (BAFF), also known as B lymphocyte stimulators (BLyS), and proliferation-inducing ligand APRIL are extremely important for the activation of autoimmune signalling pathways, which have become key targets for the treatment of IgAN. As a dual-target biological agent, telitacicept can inhibit both BLyS and APRIL cytokines, improve the function of renal immune complexes, and reduce haematuria and proteinuria, which play important roles in IgAN pathogenesis and long-term prognosis. This article reviews the role of telitacicept in IgA nephropathy and discusses its potential for use in the treatment of IgAN and other autoimmune diseases where pathogenesis is driven by B cells.

In this work, MoS2-based hybrid tubular nanostructures are facilely synthesized via a self-assembly-assisted process and evaluated as a bifunctional electrocatalyst for hydrogen evolution reactions (HERs) and oxygen reduction reactions (ORRs). By simply mixing the reactants under ambient conditions, (NH4)2MoS4/polydopamine (PDA) hybrid nanospheres are formed. The protonated dopamine is linked to tetrahedral [MoS4]2–via weak N–H···S and O–H···S interactions, causing the PDA nanospheres merging together and forming nanorods under stirring-induced shear force. Moreover, the oxidative polymerization of dopamine proceeds on the surface of the nanorods, whereas it is prohibited inside the nanorods owing to lack of oxygen, leading to outward diffusion of dopamine and hence cavitation. After annealing, the tubular morphology is perfectly retained, while ultrafine MoS2monolayers are formed due to the confinement of the framework. Benefiting from these unique structural features, the MoS2/C hybrid nanotubes possess abundant active sites and high surface area, as well as boost electronic and ionic transport, remarkably enhancing their electrocatalytic activities. The onset and half-wave potentials are 0.91 and 0.82 V, respectively, for ORR, close to those of Pt/C. Moreover, low onset potential and small Tafel slope are also observed for HER, demonstrating the potential of the hybrid nanotubes as a promising non-noble metal bifunctional electrocatalyst.

Ultralight and highly elastic reduced graphene oxide (RGO)/lignin-derived carbon (LDC) composite aerogels with aligned micron-sized pores and cell walls are prepared using a facile freeze-drying method. The presence of a small fraction of LDC in the cell walls enhances the interfacial polarization effect while almost maintaining the amount of charge carriers and conductivity of the cell walls, greatly boosting the wave absorption capability of the cell walls. RGO/LDC aerogels also show a greater number of large cell walls with better integrity than RGO aerogels, further improving the multiple reflection ability of the aligned cell walls. Synergistic effects of the multiphase cell walls and the preferred microstructures of the RGO/LDC aerogels lead to their high electromagnetic interference (EMI) shielding effectiveness of 21.3–49.2 dB at an ultralow density of 2.0–8.0 mg/cm3. This corresponds to the surface-specific SE (SE divided by density and thickness) up to 53?250 dB·cm2/g, which is higher than the values reported for other carbon- and metal-based shields. Furthermore, the critical roles that microstructures play in determining the EMI shielding performance are directly revealed by comparing the shielding performance in directions parallel and normal to cell walls, as well as in an in situ compression process.

Flexible waterborne polyurethane (WPU)/silver nanowire (AgNW) nanocomposites with unidirectionally aligned micrometer-sized pores are fabricated using a facile freeze-drying process, and their dimensions, densities, and AgNW contents are easily controllable. The high-aspect-ratio AgNWs are well-dispersed in the nanocomposite cell walls, giving the nanocomposites good compression strength and excellent electrical conductivity even at very low densities. The large conductivity mismatch between the AgNWs and WPU also induces substantial interfacial polarization that benefits the absorption of electromagnetic (EM) waves, whereas the aligned cell walls promote multireflections of the waves in the porous architectures, further facilitating the absorption. The synergistic actions of the AgNWs, WPU, and unidirectionally aligned pores lead to ultrahigh EM shielding performance. The X-band shielding effectiveness (SE) of the nanocomposites is 64 and 20 dB at the densities of merely 45 and 8 mg/cm3, respectively, and ultrahigh surface specific SE of ∼1087 dB cm3/(g mm) is achieved with only 0.027 vol % AgNWs, demonstrating that they are promising ultralight, flexible, mechanically robust, high-performance EM shielding materials.

In this article, a simple self-assembly strategy for fabricating van der Waals heterostructures from isolated two-dimensional atomic crystals is presented. Specifically, dopamine (DOPA), an excellent self-assembly agent and carbon precursor, was adsorbed on exfoliated MoS2monolayers through electrostatic interaction, and the surface-modified monolayers self-assembled spontaneously into DOPA-intercalated MoS2. The subsequent in situ conversion of DOPA to highly conductive nitrogen-doped graphene (NDG) in the interlayer space of MoS2led to the formation of a novel NDG/MoS2nanocomposite with well-defined alternating structure. The NDG/MoS2was then studied as an anode for lithium-ion batteries (LIBs). The results show that alternating arrangement of NDG and MoS2triggers synergistic effect between the two components. The kinetics and cycle life of the anode are greatly improved due to the enhanced electron and Li+transport as well as the effective immobilization of soluble polysulfide by NDG. A reversible capacity of more than 460 mAh/g could be delivered even at 5 A/g. Moreover, the abundant voids created at the MoS2–NDG interface also accommodate the volume change during cycling and provide additional active sites for Li+storage. These endow the NDG/MoS2heterostructure with low charge-transfer resistance, high sulfur reservation, and structural robustness, rendering it an advanced anode material for LIBs.

In this work, solid, hollow, and porous carbon nanofibers (SNFs, HNFs, and PNFs) were used as hosts to grow MoS2nanosheets hydrothermally. The results show that the nanosheets on the surface of SNFs and HNFs are comprised of a few grains stacked together, giving direct carbon–MoS2contact for the first grain and indirect contact for the rest. In contrast, the nanosheets inside of PNFs are of single-grain size and are distributed evenly in the mesopores of PNFs, providing efficient MoS2–carbon contact. Furthermore, the nanosheets grown on the polydopamine-derived carbon surface of HNFs and PNFs have larger interlayer spacing than those grown on polyacrylonitrile-derived carbon surface. As a result, the MoS2nanosheets in PNFs possess the lowest charge-transfer resistance, the most accessible active sites for lithiation/delithiation, and can effectively buffer the volume variation of MoS2, leading to its best electrochemical performance as a lithium-ion battery anode among the three. The normalized reversible capacity of the MoS2nanosheets in PNFs is about 1210 mAh g–1at 100 mA g–1, showing the effective utilization of the electrochemical activity of MoS2.

Electrospun polymer nanofibrous mats loaded with ionic liquids (ILs) are promising nonvolatile electrolytes with high ionic conductivity. The large cations of ILs are, however, difficult to diffuse into solid electrodes, making them unappealing for application in some electrochemical devices. To address this issue, a new strategy is used to introduce proton conduction into an IL-based electrolyte. Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) copolymer is functionalized with sulfonic acid through covalent attachment of taurine. The sulfonic acid-grafted P(VDF-HFP) electrospun mats consist of interconnected nanofibers, leading to remarkable improvement in dimensional stability of the mats. IL-based polymer electrolytes are prepared by immersing the modified mats in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM+BF4–). It is found that the SO3–groups can have Lewis acid–base interactions with the cations (BMIM+) of IL to promote the dissociation of ILs, and provide additional proton conduction, resulting in significantly improved ionic conductivity. Using this novel electrolyte, polyaniline-based electrochromic devices show higher transmittance contrast and faster switching behavior. Furthermore, the sulfonic acid-grafted P(VDF-HFP) electrospun mats can also be lithiated, giving additional lithium ion conduction for the IL-based electrolyte, with which Li/LiCoO2batteries display enhanced C-rate performance.

In this article, liquid moisture transport behaviors of dual-layer electrospun nanofibrous mats are reported for the first time. The dual-layer mats consist of a thick layer of hydrophilic polyacrylonitrile (PAN) nanofibers with a thin layer of hydrophobic polystyrene (PS) nanofibers with and without interpenetrating nanopores, respectively. The mats are coated with polydopamine (PDOPA) to different extents to tailor the water wettability of the PS layer. It is found that with a large quantity of nanochannels, the porous PS nanofibers exhibit a stronger capillary effect than the solid PS nanofibers. The capillary motion in the porous PS nanofibers can be further enhanced by slight surface modification with PDOPA while retaining the large hydrophobicity difference between the two layers, inducing a strong push–pull effect to transport water from the PS to the PAN layer.

In this work, highly flexible MoS2-based lithium-ion battery anodes composed of disordered thin MoS2nanoflakes encapsulated in amorphous carbon nanofibrous mats were fabricated for the first time through hydrothermal synthesis of graphene-like MoS2, followed by electrospinning and carbonization. X-ray diffraction as well as scanning and transmission electron microscopic studies show that the as-synthesized MoS2nanoflakes have a thickness of about 5 nm with an expanded interlayer spacing, and their structure and morphology are well-retained after the electrospinning and carbonization. At relatively low MoS2contents, the nanoflakes are dispersed and well-embedded in the carbon nanofibers. Consequently, excellent electrochemical performance, including good cyclability and high rate capacity, was achieved with the hybrid nanofibrous mat at the MoS2content of 47%, which may be attributed to the fine thickness and multilayered structure of the MoS2sheets with an expanded interlayer spacing, the good charge conduction provided by the high-aspect-ratio carbon nanofibers, and the robustness of the nanofibrous mat.

A novel approach to toughen epoxy resin with lignin, a common waste material from the pulp and paper industry, is presented in this article. First, carboxylic acid-functionalized alkali lignin (AL-COOH) was prepared and subsequently incorporated into anhydride-cured epoxy networks via a one-pot method. The results of mechanical tests show that covalent incorporation of rigid AL-COOH into epoxy networks can significantly toughen the epoxy matrix without deteriorating its tensile strength and modulus. The addition of 1.0 wt % AL-COOH gives increases of 68 and 164% in the critical stress intensity factor (KIC) and critical strain energy release rate (GIC), respectively, relative to that of neat epoxy. This article opens up the possibility of utilizing low-cost and renewable lignin feedstocks as effective toughening agents for thermoset polymers.

Highly porous three-dimensional (3D) hierarchical nanostructures suspended in aqueous media were facilely prepared via electrospinning of polyacrylonitrile (PAN)/indium tin oxide (ITO) nanofibers and collection of the hybrid nanofibers by water, followed by hydrothermally growing ZnO nanorods from the nanofibers. The large interfiber distances facilitated the uniform growth of the ZnO nanorods throughout the whole system. The suspended PAN/ITO nanofibers process excellent light trapping capability due to their centimeter-sized dimensions and hence large light penetration path. This significantly increases the probability of multiple-reflections, leading to high absorption with almost zero transmission when the size of the sample reaches 10 mm in the direction parallel to incident light. High photocurrent was generated when the nanorods-on-nanofibers was used as a photoanode. The high photocurrent density generated by the anode can be attributed to its excellent light-trapping capability brought by the large amount of interaction sites between the ZnO nanorods and light, its large contact area with electrolyte, as well as the conduction path constructed by high-content ITO nanoparticles.

Inspired by the radical scavenging function of melanin-like materials and versatile adhesive ability of mussel-adhesion proteins, dopamine-modified clay (D-clay) was successfully incorporated into polypropylene (PP) using an amine-terminated PP oligomer as the compatibilizer. Although the PP/D-clay nanocomposites exhibit intercalated morphology, the incorporation of D-clay greatly improves the thermo-oxidative stability and UV resistance of PP owing to the strong radical scavenging ability of polydopamine (PDA) and large contact area between PP and the PDA coating on clay mineral. Moreover, the reinforcement effect brought by D-clay is fairly significant at very low clay loadings probably owing to the strong interfacial interactions between the layered silicates and the compatibilizer as well as that between the compatibilizer and the PP matrix. The work demonstrates that D-clay is a type of promising nanofiller for thermoplastics used for outdoor applications since it stabilizes and reinforces the polymers simultaneously.

Dopamine-modified clay (D-clay) was successfully dispersed into polyether polyurethane (PU) by solvent blending. It is found that the incorporation of D-clay into PU gives rise to significant improvements in mechanical properties, including initial modulus, tensile strength, and ultimate elongation, at a very low clay loading. The large reinforcement could be attributed to the hydrogen bonds between the hard segments of PU and stiff D-clay layers that lead to more effective interfacial stress transfer between the polymer and D-clay. Besides, the interactions between D-clay and PU are also stronger than those between Cloisite 30B organoclay and the PU chains. Consequently, at a similar clay loading, the PU/D-clay nanocomposite has much higher storage modulus than the PU/organoclay nanocomposite at elevated temperatures.

1D hierarchical tubular MnO2nanostructures have been prepared through a facile hydrothermal method using carbon nanofibres (CNFs) as sacrificial template. The morphology of MnO2nanostructures can be adjusted by changing the reaction time or annealing process. Polycrystalline MnO2nanotubes are formed with a short reaction time (e.g., 10 min) while hierarchical tubular MnO2nanostructures composed of assembled nanosheets are obtained at longer reaction times (>45 min). The polycrystalline MnO2nanotubes can be further converted to porous nanobelts and sponge-like nanowires by annealing in air. Among all the types of MnO2nanostructures prepared, tubular MnO2nanostructures composed of assembled nanosheets show optimized charge storage performance when tested as supercapacitor electrodes, for example, delivering an power density of 13.33 kW·kg–1and a energy density of 21.1 Wh·kg–1with a long cycling life over 3000 cycles, which is mainly related to their features of large specific surface area and optimized charge transfer pathway.

A facile biomimetic method was developed to enhance the interfacial interaction in polymer-layered silicate nanocomposites. By mimicking mussel adhesive proteins, a monolayer of polydopamine was constructed on clay surface by a controllable coating method. The modified clay (D-clay) was incorporated into an epoxy resin, it is found that the strong interfacial interactions brought by the polydopamine benefits not only the dispersion of the D-clay in the epoxy but also the effective interfacial stress transfer, leading to greatly improved thermomechanical properties at very low inorganic loadings. Rheological and infrared spectroscopic studies show that the interfacial interactions between the D-clay and epoxy are dominated by the hydrogen bonds between the catechol-enriched polydopamine and the epoxy.

The electrodes with the hierarchical nanoarchitectures could offer a huge increase in energy storage capacity. However, the ability to achieve such hierarchical architectures on a multiple scale still has remained a great challenge. In this paper, we report a scalable self-assembly strategy to create bioinspired hierarchical structures composed of functionalized graphene sheets to work as anodes of lithium-ion batteries. The resulting electrodes with novel multilevel architectures simultaneously optimize ion transport and capacity, leading to a high performance of reversible capacity of up to 1600 mAh/g, and 1150 mAh/g after 50 cycles. Importantly, the process to fabricate such hierarchical structures is facile, low-cost, green, and scalable, providing a universal approach for the rational design and engineering of electrode materials with enhanced performance, and it may have utility in various applications, including biological scaffold, catalysis, and sensors.

Hybrid electrochromic materials were readily synthesized via copolymerization of aniline with p-phenylenediamine-functionalized single-walled carbon nanotubes (SWCNTs) in the presence of poly(styrene sulfonate) (PSS) dopant in an aqueous medium. Polyaniline (PANI)-grafted SWCNTs are formed, and they are uniformly dispersed in the PANI/PSS matrix. Impedance analysis shows that the charge-transfer resistances of the hybrids at all states are reduced drastically with increasing SWCNT loading. With 0.8 wt % SWCNTs, the charge-transfer resistances of the hybrid at +1.5 and −1.5 V are only about 20% and 12% of those of PANI/PSS, respectively, which is due to the greatly increased redox reactivity given by the enhanced electron transport in the hybrid and further doping function of the SWCNTs. The remarkable increase in redox reactivity leads to much enhanced electrochromic contrast from 0.34 for PANI to 0.47 for PANI-SWCNT-0.8%.

Poly(methacrylic acid)‐grafted hollow silica vesicles (PMAA‐g‐hollow silica vesicles) were obtained through a grafting‐from approach. PMAA brushes were formed by performing atom‐transfer radical polymerisation of sodium methacrylate with an initiator attached to the hollow silica spheres. PMAA‐g‐hollow silica vesicles were characterised by using TEM, thermogravimetric analysis (TGA) and FTIR spectroscopy. pH‐dependent ξpotential and 1H NMR spectra of PMAA‐g‐hollow silica vesicles were measured, and the results indicated that MAA brushes in PMAA‐g‐hollow silica vesicles had a lower ionisation degree and low solubility in acidic aqueous solution, for example, pH 3.4, but a higher ionisation degree and high solubility when the pH was higher than 7. Also it was demonstrated that calcein blue and fluorescein isothiocyanate (FITC) labelled dextran (Mn: 10 kDa) could be encapsulated in the interiors of the PMAA‐g‐hollow silica vesicles with a negligible amount in PMAA brushes at pH 2, and pH‐triggered release of calcein blue and FITC‐labelled dextran from PMAA‐g‐hollow silica vesicles was observed at pH 7.4.

A reverse‐barrier technique is used to enable the treatment of electrospun poly(vinylidene fluoride) nanofibrous membranes with supercritical carbon dioxide. The treatment induces the formation of nanopores and extended‐chain β crystallites of small lateral dimensions in the nanofibers. It also creates interfiber junctions, resulting in a remarkable improvement in mechanical properties of the membranes. The treated membranes are able to retain their shape very well after loading with an ionic liquid (IL). The ionic conductivity of the IL‐loaded membrane is very close to that of the neat IL.

The excessive use and disposal of plastic products have become a severe threat to the environment, animal welfare, and human health. Naturally synthesized, marine-degradable polyhydroxybutyrate (PHB) represents a viable green substitute for conventional plastics. However, the inherent brittleness of PHB remains a major challenge due to undesirable large spherulites and secondary crystallization. Herein, we report PHB-based (up to 70 wt %) ductile and flexible materials by facile physical blending with edible poly(vinyl acetate) (PVAc). Theoretical and experimental analyses show that entropy rather than enthalpy drives the high miscibility between two polymers. Entropic mixing turns fragile PHB spherulitic crystals (>70 μm) into myriads of ultrafine domains (<2 μm). Interfacial entanglements between PVAc and PHB further prevent secondary crystal formation of the rigid amorphous phase. The resultant biopolymer blends demonstrate mechanical properties similar to commercial polyethylene plastics, such as high ductility (elongation >500%), toughness (∼62 MJ m–3), flexibility, and shape recovery under repeated bending (180°) or twisting (360°). Under controlled composting conditions, the food-safe bioblends exhibit ∼2.4 times weight loss of virgin PHB. The proposed strategy proves applicable to other crystalline/amorphous polymeric mixtures. This discovery sheds new light on the rational design of green plastics for future sustainable electronics, agriculture, and biomedicine.

Atomic force microscopic observations on an isothermally crystallized poly(ethylene naphthalate) (PEN)/clay nanocomposite suggest that the presence of nanoclay alters the lamellar organization in PEN mainly in three ways: 1) physically blocking the crystal growth front and creating wide amorphous regions within the spherulites, which may then be filled by secondary lamellae branching out from the primary lamellae of the same spherulite, or primary lamellae developed from other nearby nucleating centers; 2) inducing random twisting of lamellae; and 3) causing irregular crystallite growth fronts, with the protrusion of some leading lamellae. In particular, the physical hindrance imposed by clay tends to be more prevalent for lamellae that grow roughly perpendicular to the clay long axes. This may give rise to an anisotropic crystalline morphology if the clay layers exhibit a preferred orientation induced by flow.

Copolymerization of aniline with octa(aminophenyl) silsesquioxane (OAPS) was performed, which resulted in polyaniline‐tethered, polyhedral oligomeric silsesquioxane (POSS‐PANI), with star‐like molecular geometry. The spectro‐electrochemical studies show that the electrochromic contrast of POSS‐PANI is much higher than that of polyaniline (PANI). The great improvement can be attributed to the more accessible doping sites and the facile ion movement during the redox switching, brought by the loose packing of the PANI chains. This was evidenced by a drastic increase in ionic conductivity, a decrease in the electrical conductivity, and a decrease in the crystallinity and crystal size, with the increase of the OAPS concentration in the POSS‐PANI.

A poly(ethylene terephthalate)/clay nanocomposite (PET/clay) was prepared via in situ polymerization, in which the clay was modified with 12‐aminododecanoic acid (ADA). A compatibilizer containing an amino and an ester group was introduced into the PET/ADA‐clay system, which can attach to ADA‐clay through ionic interaction and be incorporated into PET chains through transesterification. The compatibilizer‐modified ADA‐clay was first formed in a pretreatment process and then participated in polymerization. The compatibilizer, as an intermedium between organoclay and polymer, improved clay dispersion in PET matrix. The PET/clay nanocomposite prepared by this novel method possesses significantly higher storage modulus than does neat PET. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1057–1064, 2006

Thermally stable organically modified clays based on 1,3‐didecyl‐2‐methylimidazolium (IM2C10) and 1‐hexadecyl‐2,3‐dimethyl‐imidazolium (IMC16) were used to prepare poly(ethylene naphthalate) (PEN)/clay nanocomposites via a melt intercalation process. The clay dispersion in the resulting hybrids was studied by a combination of X‐ray diffraction, polarizing optical microscopy, and transmission electron microscopy. It was found that IMC16 provided better compatibility between the PEN matrix and the clay than IM2C10, as evidenced by some intercalation of polymer achieved in the PEN/IMC16‐MMT hybrid. The effects of clay on the crystal structure of PEN were investigated. It was found that both pristine MMT and imidazolium‐treated MMT enhanced the formation of the β‐crystal phase under melt crystallization at 200 °C. At 180 °C, however, the imidazolium‐treated MMT was found to favor the α‐crystal form instead. The difference in clay‐induced polymorphism behavior was attributed to conformational changes experienced by the clay modifiers as the crystallization temperature changes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1040–1049, 2006

Light-emitting alternating copolymers of 9,9-dialkylfluorene and N-hexylcarbazole with conjugated (P1 and P2) and δ-Si interrupted (P3 and P4) structures have been synthesized. The linear tetrahedral polymer P3 and hyperbranched tetrahedral polymer P4 were synthesized from two novel tetrahedral dibromo/tetrabromo precursors (2 and 3, respectively). The thermal and optical properties of all polymers in solution and the condensed state were investigated. A comparative study on the optical properties of P1−P4 showed that, in the condensed state, P1 and P2 suffered seriously from concentration quenching (significant red shift in emission maximum, broadening in emission spectrum and tremendous decrease in quantum yield), whereas the two δ-Si interrupted P3 and P4, particularly the latter, were tremendously less or not prone to self-aggregation such that they did not show significant concentration quenching in the condensed state. We represent in this paper an effective approach, a tetrahedral approach, for the synthesis of nonaggregating optoelectronic polymers.

A series of nano-hybrid light emitting dots with diameter range from 2 nm to 4 nm were synthesized through grafting organic conjugated chains directly onto an inorganic rigid cage polyhedral oligomeric silsesquioxanes (POSS). The effect of chain length, side groups, polarity of solvents on the property of light emitting dots were studied using FTIR, XRD, DSC, UV, PL, AFM and SEM. The unique structure of these nano-hybrid dots renders them with excellent PL properties which are much different from bulk organic molecules or conjugated polymers. The incorporation of conjugated molecules onto POSS transforms the oligo-conjugated arms from crystalline state to non-crystalline solid which can be solution processed. The PLQE (PL quantum efficiency) of the oligo-conjugated arms in condensed state increases significantly after grafting onto POSS. The light emitting dots are very sensitive to the polarity of organic solvents due to their nano-scaled size. PL spectrum of the nano-hybrid dots in solid film was blue shift from that in most of organic solvents.

Two series of difunctional proton acceptors, stilbazole derivatives 4a–c and 6a–c with different spacers, oligo(methylene) and oligo(ethylene glycol), respectively, were synthesized. Hydrogen‐bonded polymeric complexes 4/7 and 6/7 and trimeric complexes 4/82 and 6/82 (7 and 8 are aromatic dicarboxylic acids and monocarboxylic acids, respectively) were prepared, and their liquid crystallinity was examined. The effects of the spacer in 4, 6, and 7 and the terminal group in 8 on the thermal behaviors of hydrogen‐bonded complexes were investigated using differential scanning calorimetry and polarizing optical microscopy. X‐ray diffraction at elevated temperatures was used to verify liquid crystal phases. The study showed that the phase transition temperatures for isotropic to nematic (TI–Ns) of polymeric complexes 4/7 and 6/7 in general decreased with the increase in length of spacer in the corresponding proton donors 7. The increase in length of the proton acceptors 6 led to a drop of TI–Ns of the corresponding complexes 6/7; however, the TI–Ns of complexes 4/7 did not show any correlation with the spacer length in 4. In contrast, the increase in length of the terminal group in 8 resulted in a slight decrease in TI–Ns of trimeric complexes 4/82, but had a negligible effect on the TI–Ns of 6/82 because of the presence of the more flexible spacer in the proton acceptors 6. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4731–4743, 2005

The structures and properties of liquid‐crystalline polymers containing laterally attached p‐terphenyl and p‐pentaphenyl have been studied. In contrast to their mesogenic groups, that is, p‐terphenyl and p‐pentaphenyl, the polymers have much lower crystallinity and also lower nematic‐to‐isotropic transition temperatures. The significant depression in crystallinity can be attributed to flexible chain segments laterally attached to the oligo p‐phenylene rods, which prevent close packing of the rods and thus disrupt the crystallization. The destabilization of the liquid‐crystalline phase is due to the diluting effect of the flexible polymer backbones; that is, the concentration of the mesogenic groups is reduced. The polymer containing p‐pentaphenyl can still exhibit good solubility in common solvents and emit light at about 402 nm in the solvent tetrahydrofuran. In the solid state, the emission redshifts to 418 nm, which is fairly close to the blue‐light emission. An interdigitated packing structure of mesogenic groups has been proposed to represent the structure of the polymer in the oriented state. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3394–3402, 2005

Nylon 12 (PA12) nanocomposites with different organoclay loadings were successfully prepared by melt compounding. X‐ray diffraction indicated the dominance of the exfoliated clay morphology throughout the matrix after mixing in a Brabender twin‐screw extruder, in accordance with transmission electron microscopy observations. Thermogravimetric analysis showed that the thermal stability of the PA12 matrix was improved by about 20 °C on incorporation of only 5 wt% clay. Tensile and nanoindentation tests indicated that the elastic modulus and the hardness steadily increased by about 52 % and 67 %, respectively, with a clay concentration up to 5 wt%, while improvements in tensile strength were limited. Impact strength decreased linearly by about 25 % as the clay loading increased (up to 5 wt%), indicating an embrittlement due to clay addition, as evidenced by SEM observation on the fracture surfaces. The embrittling effect may be due to the weak interfacial adhesion between the clay platelets and the polymer matrix. Copyright © 2004 Society of Chemical Industry

A poly(ethylene terephthalate) (PET)/montmorillonite clay nanocomposite was synthesized via in situ polymerization. Microscopic studies revealed that in an isothermal crystallization process, some crystallites in the nanocomposite initially were rod‐shaped and later exhibited three‐dimensional growth. The crystallites in the nanocomposite were irregularly shaped, rather than spherulitic, being interlocked together without clear boundaries, and they were much smaller than those of neat PET. With Avrami analysis, the isothermal crystallization kinetic parameters (the Avrami exponent and constant) were obtained. The rate constants for the nanocomposite demonstrated that clay could greatly increase the crystallization rate of PET. The results for the Avrami exponent were consistent with the observation of the rodlike crystallites in the PET/clay nanocomposite during the initial stage. Wide‐angle X‐ray scattering and Fourier transform infrared studies showed that, in comparison with neat PET, the crystal lattice parameters and crystallinity of the nanocomposite did not change significantly, whereas more defects may have been present in the crystalline regions of the nanocomposite because of the presence of the clay. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1381–1388, 2004

Fracture properties and deformation mechanisms of nanoclay‐reinforced maleic anhydride‐modified polypropylene (MAPP) were investigated. Elastic–plastic fracture mechanics was employed to characterize the toughness in light of substantial postyield deformation for the reinforced MAPP. Upon introduction of 2.5 wt % clay loading in maleated MAPP, it was observed that tensile strength, modulus, and fracture initiation toughness concomitantly increased substantially. Continued increase in clay loading thereafter only led to stiffening and strengthening effects to the detriment of fracture toughness. A plot of the J‐integral initiation fracture toughness versus the plastic zone size demonstrated that toughening arose from plastic deformation in the reinforced matrix. Careful examination of deformed tensile specimens using small angle X‐ray scattering (SAXS) showed 2.5 wt % clay gave rise to the highest equatorial scattering, which indicates the presence of microvoids in the matrix. The SAXS results were consistent with that shown in subcritically loaded crack‐tip deformation zone using transmission electron microscopy. Thus, both macroscale three‐point bend fracture data and SAXS results led us to consistent findings and conclusions. Further increase in clay loading above 2.5 wt % reduced the scattering the matrix plasticity and thus the fracture toughness. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2759–2768, 2004

The effects of clay on polymorphism of polypropylene (PP) in PP/clay nanocomposites (PPCNs) under various thermomechanical conditions were studied. In extruded PP and PPCN pellet samples, only α-phase crystallites existed, as they were prepared by rapidly cooling the melt extrudates to room temperature. Under compression, β-phase crystallites can develop in neat PP under various thermal conditions, of which isothermal crystallizing at 120 °C gave the highest content of β-phase crystallites. In contrast, no β-phase crystallite was detected in the PPCN samples prepared under the same conditions. This indicated that clay significantly inhibits the formation of β-phase crystallites. The likely reason is that the presence of clay in PPCNs greatly sped up the crystallization process of the α phase, whereas it had an insignificant effect on the crystallization rates of the β phase. The results also showed that clay may slightly promote the formation of γ-phase PP crystallites in PPCNs. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1810–1816, 2004

Two liquid-crystalline polyesters (LCPs) with different chain rigidities were synthesized and melt-blended with polycarbonate (PC) at an LCP concentration of 2 wt %. The first LCP (LCP1) was based on hydroxybenzoic acid (HBA), hydroquinone (HQ), sebacic acid (SEA), and suberic acid (SUA) and contained a relatively high concentration of flexible units (SEA and SUA). The other one (LCP2) was based on HBA, hydroxynaphthoic acid, HQ, and SEA and contained a lower concentration of flexible units. LCP2 had a much lower melting point, a higher clearing temperature, and a lower shear viscosity than LCP1. The blending was carried out at 265, 280, and 300°C for both systems. The extent of the viscosity reduction induced by the addition of LCP1 depended on the compounding temperature, and the lowest viscosity was achieved with blending at 280°C. This was attributed to the large interfacial area and interactions between the flexible segments of LCP1 and PC chains at the interface. For PC/LCP2, the viscosity reduction was not significantly dependent on the compounding temperature, and when it was compounded at 280°C, its viscosity was significantly higher than that of PC/LCP1 at high shear rates, even though LCP2 had lower viscosity. A scanning electron microscopy study revealed that, with compounding at 265 and 280°C, LCP2 was poorly dispersed in the PC matrix in comparison with LCP1, and the glass-transition-temperature depression caused by the addition of LCP2 was relatively small. This indicated that interfacial interactions in PC/LCP2 were weaker, thereby explaining their different rheological behavior in comparison with PC/LCP1. With compounding at 300°C, the compatibility of both systems improved because of transesterification reactions, but this did not lead to a lower viscosity because of the lack of physical interfacial interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 960–969, 2004

High‐density polyethylene (HDPE) was reinforced with expanded and untreated graphite in a melt‐compounding process. Viscosity increased upon addition of graphite phase, with the expanded graphite (EG) showing more dramatic rise than the untreated graphite (UG) in viscosity. The increase in viscosity was attributed to the increased surface‐to‐volume ratio for the EG filler after acid treatment. Electrical conductivity also increased from that pertaining to an insulator to one characteristic of a semiconductor. The EG system showed a lower percolation threshold for transition in conductivity compared to that in the UG system. DSC results indicated that the fillers acted as a nucleating agent in inducing the crystallization of HDPE in the composites. However, the overall degree of crystallinity and melting temperature of HDPE decreased with the addition of EG and UG. Mechanical properties improved as a function of filler content but the overall enhancement was not impressive. It was conjectured that the filler–matrix interface was not optimized in the melt‐mixing process. However, the role of EG as a reinforcement phase for both electrical and mechanical properties was unambiguously established. The EG composites demonstrated potentially useful attributes for antistatic, barrier, mechanical, electrical, and cost‐effective applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:2781–2788, 2004