Super Strong and Tough Polybenzimidazole/Metal Ions Coordination Networks: Reinforcing Mechanism, Recyclability, and Anti-Counterfeiting Applications.

Nature has provided many delicate strategies for optimizing the structural characteristics of biological materials. One such strategy is the strengthening and toughening of matrix materials by aduandant and hierarchically arranged non-covalent crosslinking. However, efficient strengthening and toughening of high-performance aromatic polymers by non-covalent bonds has rarely been reported yet.

An efficient and general method for the synthesis of stable isotope deuterium labeled phthalate esters.

An efficient and general synthetic route of deuterium-labeled phthalate esters is described with high isotopic enrichment and excellent chemical purities using inexpensive and readily available o-xylene-D as labeled starting material. The structures and isotope-abundance were confirmed via H NMR and mass spectrometry. These deuterium labeled phthalate esters can be used as analytical reference standards for the detection of plasticizer residues in soil, water, food, plastic products, etc.

Lysosome-targetable selenium-doped carbon nanodots for in situ scavenging free radicals in living cells and mice.

Lysosome-targetable selenium-doped carbon nanodots (Lyso-Se-CDs) that can efficiently scavenge lysosomal •OH in living cells and mice were designed in this research. Se-CDs with redox-responsive fluorescence (λ = 379 nm, λ = 471 nm, quantum yield = 7.1%) were initially synthesized from selenocystine by a facile hydrothermal method, followed by the surface modification with morpholine, a lysosome targeting moiety.

Facile strategy to prepare polyimide nanofiber assembled aerogel for effective airborne particles filtration.

Polyimide nanofiber (PINF) aerogel materials have received extensive attention as heat insulation, sensors and filtration media due to their excellent thermodynamic properties and unique porous structure. However, PINF must be difficult to disperse in organic solvents (dioxane or dimethyl sulfoxide) and dimensional instability has been regarded as issues that limits the preparation of PINF aerogels, especially in the water. So, it is of great significance to prepare polyimide aerogels with stable structure using water as a dispersant.

Hyper-Cross-Linked Polymers-Derived Porous Tubular Carbon Nanofibers@TiO toward a Wide-Band and Lightweight Microwave Absorbent at a Low Loading Content.

An enormous challenge exists in the achievement of one-dimensional (1D) dielectric carbon composite high-performance microwave absorbents at a low filling ratio. Porous/core-shell dual microstructures have been considered as the potential candidate for designing remarkable microwave absorbers with strong absorption and wide band. Herein, novel multiple-structured tubular carbon nanofibers@TiO (TCNFs@TiO) hybrids were constructed via the sequential steps of hydrolysis and pyrolysis.

Mechanical strong stretchable conductive multi-stimuli-responsive nanocomposite double network hydrogel as biosensor and actuator.

Multi-stimuli- responsive mechanical strong stretchable hydrogel has grabbed extensive attention in recent years. Here, a novel stretchable conductive biocompatible near-infrared light(NIR)-/thermal-/pH-/ionic concentration- responsive carboxymethyl chitosan (CMCTs)/graphene oxide (GO)/poly(N-isopropylacrylamide)(PNIPAm) nanocomposite double network hydrogel was fabricated through a simple one-pot free radical polymerization, which is initiated by ultraviolet (UV) light and using N-(3-dimethylaminopropyl)-N-ethylcarbodiimidehydrochloride (EDC) and N,N'-bis(acryloyl)cystamine (BAC) as cross-linkers respectively, instead of toxic organic molecules. When the concentration of CMCTs, GO, EDC and BAC is 22.

Vitrimer Chemistry Assisted Fabrication of Aligned, Healable, and Recyclable Graphene/Epoxy Composites.

The alignment is a key factor to fully exploit the potential of graphene in reinforcement of polymer composites. However, it is still a challenge to orientate graphene in thermosets because of the insoluble and infusible features of the later. In this paper, we report a facile and scalable hot press method to fabricate aligned graphene nanoplate (GnP)/epoxy composites by utilizing the dynamic character of epoxy vitrimer.

High Performance Microfiltration Composite Membranes Based on Phenolphthalein Poly(ether sulfone) Nanofibrous Substrate with Hydrophilic Coating.

In the present paper, Phenolphthalein poly(ether sulfone) (PES-C) nanofibrous membranes were prepared via solution-blowing technology and polyvinylpyrrolidone (PVP) which would be converted to stable gels by reaction with potassium persulfate (K₂S₂O) was immobilized on the surface of nanofibers. The influence factors such as PVP concentration and depositing time were optimized to obtain the composite nanofibrous membranes. The membranes were characterized by Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Wide-angle X-ray diffraction (WAXD), X-ray photoelectron spectroscopy (XPS) and Water contact angles (WCA), etc.

Tough robust dual responsive nanocomposite hydrogel as controlled drug delivery carrier of asprin.

Smart mechanical strong hydrogels have gained increasing attention in the last decade. A novel tough robust biocompatible and dual pH- and temperature- responsive poly (N-isopropylacrylamide)/clay (Laponite XLS)/gold nanoparticles (Au-S-S NPs)/caboxymethyl chitosan (CMCTs) nanocomposite hydrogel was synthesized by a facile one-pot in situ free radical polymerization, using clay and Au-S-S NPs as the cross-linkers instead of toxic organic molecules. By tuning the crucial factors, concentration of Au-S-S NPs, CMCTs and clay, the obtained hydrogels exhibited the highest tensile stress of 535.

Mechanically strong dual responsive nanocomposite double network hydrogel for controlled drug release of asprin.

Mechanically strong dual/multi-stimuli-responsive smart hydrogels have attracted extensive attention in recent years. A novel tough, mechanical strong and biocompatible dual pH- and temperature- responsive poly (N-isopropylacrylamide) /clay (laponite XLG)/carboxymethyl chitosan (CMCTs) /genipin nanocomposite double network hydrogel was synthesized through a facile, one-pot free radical polymerization initiated by the ultraviolet light, using clay and the natural molecular-genipin as the cross-linkers instead of toxic organic molecules. Crucial factors, the content of CMCTs, clay and genipin, for synthesizing the mechanical strong hydrogels were investigated.

Preparation of Solution Blown Polyamic Acid Nanofibers and Their Imidization into Polyimide Nanofiber Mats.

Solution blow spinning (SBS) is an innovative process for spinning micro/nanofibers. In this paper, polyamic acid (PAA) nanofibers were fabricated via a SBS apparatus and then imidized into polyimide (PI) nanofibers via thermal process. The morphology and diameter distributions of PAA nanofibers were determined by scanning electron microscope (SEM) and Image Tool software, the processing parameters, including PAA concentration, solution feeding rate, gas pressure, nozzle size, and receiving distance were investigated in details.

Mechanically strong and pH-responsive carboxymethyl chitosan/graphene oxide/polyacrylamide nanocomposite hydrogels with fast recoverability.

The biocompatible, quickly recoverable, mechanically strong and tough polymer hydrogels have great potential for biomedical applications. A novel carboxymethyl chitosan (CMCTs)/graphene oxide (GO)/polyacrylamide (PAM) nanocomposite (NC) hydrogel with excellent mechanical performance was synthesized through a facile, one-pot free radical polymerization, using GO nanosheets as the crosslink centers instead of toxic organic molecules. The content of GO nanosheets and CMCTs has great influence on the mechanical properties of CMCTs/GO/PAM NC hydrogels.

Mussel-adhesive-inspired fabrication of multifunctional silver nanoparticle assemblies.

The assembly of metal nanoparticles (NPs) has attracted a great deal of attention recently because of their collective properties that could not be exhibited by individual NPs. Here a one-step approach was reported for the fabrication of spherical silver NP assemblies (AgNAs). The formation of AgNAs simply included the stirring of silver ammonia and 3,4-dihydroxy-l-phenylalanine (DOPA) in aqueous solution at room temperature, in which DOPA acted as a reductant for AgNPs first because of its reducing ability and then directed the assembly of AgNPs into AgNAs.

Tuning bio-inspired skin-core structure of nascent fiber via interplay of polymer phase transitions.

The properties of polymer fibers are determined by their inner structures. We performed dynamic Monte Carlo simulations of early-stage solidification in the fluid filaments of stretched polymer solutions after extrusion into a coagulation bath upon fiber spinning. We observed that the radial temperature gradient dominates polymer crystallization to form an oriented crystalline skin (from single to multiple layers), while the radial non-solvent influx dominates phase separation to form a concentrated but less oriented core.

Helical organic nanotubes from simple chiral building blocks.

Utilizing simple organic chiral (S)-(-)- and (R)-(+)- 1,1'-binaphthyl-2,2'-diamino as building blocks, one-dimensional chiral nanofibers/tubes were assembled via a simple process. Morphology and structure of the building blocks and the assemblies were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), while formation and properties of the assemblies were studied by ultraviolet-visible (UV-Vis) spectrophotometer, Fourier transform infrared (FTIR) spectrometer, X-ray diffractometer (XRD) and Circular dichroism (CD) spectropolarimeter. Results show that left-handed and right-handed nanofibers were successfully assembled via this method, and the structure and morphology of the assembled nanofibers are heavily dependent on assembling conditions and intrinsic molecular information of the building blocks.

Construction of robust enzyme nanocapsules for effective organophosphate decontamination, detoxification, and protection.

Nanocapsules of organophosphorous hydrolase with enhanced enzyme activity and stability are prepared via in situ polymerization, providing a novel class of nanoparticles for the decontamination and detoxification of organophosphates such as chemical warfare agents and pesticides. Using the nanocapsules as building blocks, bioactive nanocomposites are also fabricated, enabling their use for organophosphate protection.

Tuning hierarchically aligned structures for high-strength PMIA-MWCNT hybrid nanofibers.

Novel hierarchically aligned PMIA-MWCNT hybrid nanofibers with a robust tensile strength of 316.7 MPa were prepared by a facile electrospinning process. The critical roles of humidity and MWCNT contents in tuning hierarchically aligned structures were first proposed, and a two-step break mechanism upon external stress was confirmed.

Study on morphology and characterization of poly(mphenylene isophtalamide)/multi-walled carbon nanotubes composite nanofibers by electrospinning.

Electrospinning technique is the main method of preparing polymer nanofiber simply, directly and continuously at present. In this work, electrospinning blend solution was prepared by in-situ polymerization using acid-modified multi-walled carbon nanotubes (MWNTs), m-phenylenediamine (MPD) and isophthaloyl chloride (IPC). And then composite nanofibers were prepared by electrospinning.

Effects of three parameters on the diameter of electrospun poly(ethylene oxide) nanofibers.

The combined use of two techniques namely electrospray and spinning is made use in a highly versatile technique called electrospinning, which produces the diameter of polymer fibers range from nanometer to sub-micron. In this work, we have studied effects of adding LiCl on the morphology and diameter of electrospun poly(ethylene oxide), and we have also evaluated systematically the effect of three important solution parameters on the morphology of electrospun poly(ethylene oxide): molecular weight, solution viscosity and electrical conductivity. We find that molecular weight is strongly correlated with the formation of bead defects in the fibers, the smaller molecular weight, the more beads defect density.

Dynamic rheological studies of poly(p-phenyleneterephthalamide) and carbon nanotube blends in sulfuric acid.

We have studied the dynamic scanning of liquid-crystalline (LC) poly(p-phenyleneterephthalamide) sulfuric acid (PPTA-H(2)SO(4)) solution, and its blend with single-walled carbon nanotubes (SWNTs), by using a flat plate rotational rheometer. The effects of weight concentration and molecular weight of PPTA, as well as operating temperature, on dynamic viscoelasticity of the PPTA-H(2)SO(4) LC solution system are discussed. The transition from a biphasic system to a single-phase LC occurs in the weight concentration range of SWNTs from 0.