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Flexible nanocomposite dielectrics with high dielectric constant and discharge energy density have broad application prospects in the field of energy storage. However, dielectrics with high dielectric constant tend to have a high dielectric loss. Herein, we prepared a dielectric composite material with ultra‐high discharge energy density by modifying the interface between nanoparticles and poly(vinylidene fluoride‐co‐hexafluoropropylene) (P[VDF‐HFP]). After coating a shell of insulating amorphous SiO2 (~7 nm) outside the barium titanate (BT), the electric field concentration and current density inside BT particles can be significantly reduced. In addition, coating the SiO2 shell with a polydopamine (PDA) shell (~7 nm) not only enhances the interface interaction between the nanoparticles and the polymer matrix, but also can form lots of microcapacitors in the composite. As a result, an ultra‐high discharge energy density of 13.78 J/cm3 at the expense of relatively inconspicuous efficiency (~59.8%) in the BT@SiO2@PDA/P (VDF‐HFP) with 2.5 wt% loading has been achieved under 460 kV/mm. This is mainly attributed to the increases of dielectric constant from 12.1 to 14.2 and the relatively low dielectric loss (0.086) at 100 Hz. Moreover, compared with the pure P (VDF‐HFP) (400 kV/mm), the breakdown voltage of the composite with 2.5 wt% loading is surged to 460 kV/mm, which benefited from the hindrance of nanoparticles on carrier migration at low content. This work has realized a thin‐film dielectric with ultra‐high discharge energy density through a novel design of the nanoparticle structure, providing a theoretical direction for the development of polymer dielectric capacitors. [ABSTRACT FROM AUTHOR]

Fragment‐dummy‐template molecularly imprinted polymers‐Mn doped ZnS QDs (FMIP−Mn doped ZnS QDs) were synthesized by surface imprinting technique and specifically recognize microcystin (MC), especially MC‐LR, MC‐RR and MC‐YR. Pentylbenzene and L‐arginine were used as fragment dummy template of MC to form specific recognition site cavity. The introduction of dummy template reduced the toxicity and cost of MC as template in the synthesis process. When MC was added to the FMIP, the room temperature phosphorescence (RTP) intensity is quenched regularly, thereby achieving the effect of detecting MC. The two‐fragment‐dummy‐template molecularly imprinted polymers‐Mn doped ZnS QDs (FMIP‐1) have distinct linearly RTP quenching toward MC in the concentration range of 0.0025‐0.0175 nM. The linear relationship between ΔP/P0 and CMC‐LR, CMC‐YR and CMC‐RR were observed with the regression equation ΔP/P0=0.0150+24.70CMC‐LR, ΔP/P0=0.0995+21.38CMC‐YR, and ΔP/P0=0.101+16.96CMC‐RR (where concentration was in nM), with the detection limit of 0.25 pM, 1 pM and 0.6 pM, respectively. This method was applied to detect MC in water and freshwater products. The method have the potential for effective detection of other harmful substances in the complicated matrix. [ABSTRACT FROM AUTHOR]

A facile method for fabricating polymer carbon dots (PCDs) with characteristic dual-emission at 570 and 620 nm by 1,8-naphthalenediol in n-propanol solvents was designed. The synthesised PCDs possessed fluorescence enhancement performance toward the water in organic solvents. Based on this peculiar phenomenon, a highly efficient fluorescent probe for water detection in organic solvents such as N,N-dimethylformamide, dimethyl sulfoxide and n-propanol was established with a wide detection range from 0 to 50%. The probe can also be utilised to determine water content in other organic solvents. The practical application was explored by studying the response of PCDs toward the water in various spirit samples. This method may offer a new way of detecting water in organic solvents by PCDs. [ABSTRACT FROM AUTHOR]

In this work, a novel naked eye and fluorescence sensor for acetylcholinesterase (AChE) determination based on copper/silver nanoclusters (Cu/Ag NCs) was developed. L‐Histidine protected Cu/Ag NCs were prepared and exhibited superior properties compared with copper nanoclusters, with the quantum yield increased from 4.3% to 13.2%. The fluorescence of Cu/Ag NCs can be easily quenched by 2‐nitro‐5‐thiobenzoate anion (TNB) owing to the inner filter effect. TNB is the product between 5′‐Dithiobis‐(2‐nitrobenzoic acid) (DTNB) and thiols. However, AChE can specially catalyze acetylthiocholine (ATCh) to hydrolyze and release biothiols (TCh). Based on this, the determination of AChE was achieved by introducing DTNB. A naked eye sensor was also constructed owing to the color change. [ABSTRACT FROM AUTHOR]

Morphological, thermal, and mechanical features of electrosprayed and electrospun deposition of the silk-inspired polyurethane (PU) containing GlycineAlanineGlycineAlanine (GlyAlaGlyAla, the featured peptide sequence of silkworm silk fibroin) tetrapeptide, which was synthesized by the traditional liquid-phase peptide synthesis method and the classical two-step polymerization method using Boc-protected amino acids and diisocyanates as starting materials, were characterized. The results show that the synthesized silk-inspired PU dissolved in tetrahydrofuran (THF) can be easily electrosprayed or electrospun into the film form, although its molecular weight ranging from 13,000 to 15,000 is quite low. Elastomeric fibrous membranes with surface morphologies of 'droplets,' 'bead-on-string,' and 'nonwoven fibers' have been obtained by electrospraying and electrospinning the silk-inspired PU/THF solution of varying concentrations. The thermograms confirm high thermostability of the silk-inspired PU between 350 and 400°C due to the polar peptide linkages. The tanδ peak of dynamic mechanical analysis curve corresponding to its glass transition temperatures is detected at −34.3°C. Its elongation at break is about 140-150%, and the breaking tensile strength ranges from 22 to 27 MPa, which is consistent with the data of other PUs containing l-alanine residue. Information provided by this study can be used to better understand the correlation between the natural and man-made silk polymers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40245. [ABSTRACT FROM AUTHOR]

Biomedical polyurethane (BPU) and silk fibroin have similarly molecular architecture in their primary and aggregate structure, both of which have amide bonds and microphase separation, and they have been employed as scaffold materials for biomedical applications. Based on this, as the featured peptide sequence of silkworm silk fibroin, GlycineAlanineGlycineAlanine (GlyAlaGlyAla) tetrapeptide was synthesized by using traditional liquid-phase peptide synthesis method with Boc-protected glycine and alanine as starting materials, and was transformed to its derivative with two amine-terminated functional groups. The derivative was introduced as a chain extender into the backbone to form the hard segment of a silk-inspired PU with urea-linkage. Related measurements show that molecular weight of the synthesized silk-inspired PU ranged from 13,000 to 15,000. Fourier transform infrared (FTIR) absorption bands of Amides I and II are at 1651 cm−1 and 1534 cm−1, and Raman absorption band of Amide III is at 1302 cm−1. UV-Vis absorption peak of the silk-inspired PU is at 266 nm. This new concept and strategy may allow the fabrication of a new class of thermoplastic polyurethane elastomers to mimic the structure and properties of silk fibroin of silkworms and spiders. Information provided by this study may be used to better understand the correlation between the natural and man-made materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]