Design of co-continuous structure of cellulose/PAA-based alkaline solid polyelectrolyte for flexible zinc-air battery.

In order to prepare high ionic conductivity and robust mechanical properties of alkaline solid polyelectrolyte (ASPE) for applications in flexible wearable devices, a co-continuous structure membrane was designed using in-situ polymerization to introduce cross-linked polyacrylic acid (N-PAA) into the cellulose network constructed by regenerated degreasing cotton (RDC). The resultant ASPE membrane showed high ionic conductivity (430 mS·cm-1 at 25 °C), strong mechanical properties, and excellent alkaline stabilities, proving the viability of cellulose for use in energy storage systems. Surprisingly, the sandwich-shaped zinc-air battery assembled using RDC/N-PAA/KOH membranes as electrolytes exhibits superior values of cycling stability, discharge time, specific capacity (731.5 mAh·g-1), peak power density (40.25 mW·cm-2), and mechanical flexibility. Even under bending conditions, the zinc-air batteries still possess stable energy supply performance, suggesting this novel solid polyelectrolyte has promising application for wearable technology.

Polyphosphazene-Functionalized Microspheres as Efficient Catalysts for the Knoevenagel Reaction under Mild Conditions.

Inspired by the formation of microspheres by hexachlorocyclotriphosphazene and 4, 4'-sulfonyldiphenol, polyphosphazene-functionalized microspheres were developed. Benefits from the supported supper basic phosphazene, the yield exceeded 99 % at room temperature in the manner of second-order reaction kinetics toward Knoevenagel reaction and was still maintained at 99 % after 16 runs. In the experimental temperature from 0 °C to 90 °C, the yield increased from 92 % to 99 %, reflecting that the catalyst had strong applicability under mild conditions. This behavior was conducive to energy conservation. Meanwhile, simple separation and recovery further enhanced this advantage. In addition, the catalyst was also found to be insensitive to aqueous solution or organic solvents such as toluene, THF, EtOH and CH3 CN. This property gave the Knoevenagel reaction a vast choice. All these features exhibit that this novel catalyst is an attractive and applicable alternative in organic synthesis.

Hofmeister effect on the viscosity properties of gelatin in dilute solutions.

The effect of various Hofmeister anions on the molecular conformation of gelatin in dilute solutions was investigated by viscosity, optical rotation and dynamic light scattering (DLS). The results showed that the intrinsic viscosity of gelatin decreased in the presence of the kosmotropic anions such as Citrate3-, SO42-, H2PO4- and MeCOO-, whereas it was increased with the addition of chaotropes such as Cl- and KSCN-. Furthermore, the intrinsic viscosity of gelatin was directly correlated to the hydration entropy of kosmotropic anions, suggesting that the decrease of the intrinsic viscosity was attributed to the strong hydration effect of kosmotropes. The strong dehydration of gelatin facilitated the folding of the polymer chains into helix bundles, validated by the results of optical rotation. On the contrary, the chaotropic anions could interact directly with polypeptide backbones, and the intrachain hydrogen bonds were destroyed. As a result, the polymer chains expanded, which was confirmed by DLS data, and the intrinsic viscosity was increased. These observations indicate that the molecular conformation of gelatin can be modulated by Hofmeister anions.

The sensitive "Turn-on" fluorescence platform of ascorbic acid based on conjugated polymer nanoparticles.

Ascorbic acid (AA) is very important for maintaining the normal physiological processes of the organism. In order to overcome the shortcomings of existing methods, such as lower sensitivity, complex operations and expensive instruments, it is urgent to develop a simple and rapid method for the determination of AA in the field of food and pharmaceutical preparations. Conjugated polymer nanoparticles (CPNs) have lately aroused wide concerns because of excellent optical properties, biocompatibility and stability. In our work, a CPNsPBOC-COOH fluorescence platform based on Poly [3-{2,5-bis (2-ethyl-hexyloxy)]-phenyl}-vinyl}-9-octyl-carbazole] (PBOC) and Polystyrene-maleic anhydride (PSMA), was prepared for the quantitative detection of AA. Experimental results were showed that this platform was highly selective and sensitive to AA. The concentration of AA detected by the fluorescence platform has a linear relationship in the range of 0.57-17.10 µM. The limit of detection (LOD) is 10 nM, which is lower than other methods reported. More interestingly, the fluorescence of CPNsPBOC-COOH can be controlled by logic gates with Fe3+ and AA. Finally, the designed fluorescence platform has been successfully applied to the analysis of AA in actual samples (vitamin C tablets, mouse serum and plasma), indicating the designed platform with a good feasibility.

Structural characterization and properties of polyols plasticized chitosan films.

In this study, the influence of different polyols such as glycerol, xylitol and maltitol on the crystalline structure and thermal properties of chitosan films were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The concentration of polyol was fixed at 20 wt%. FTIR result showed that the addition of polyols weakened the hydrogen bonding between chitosan molecules, whereas the electrostatic interactions remained nearly unchanged. Structural analysis revealed that the plasticizer which promoted the crystallization of chitosan was moisture rather than polyol contained in the polymer films. DSC result indicated that glycerol plasticized film had a lower glass transition temperature (Tg) and lower melting temperature (Tm). The low thermal transition temperatures suggested that the moisture content is higher in glycerol plasticized film, which was evidenced by TGA result. In addition, the polyols incorporation resulted in a decrease of the tensile strength of chitosan films, while their ductility was improved. These observations indicate that the addition of polyols as plasticizers could regulate the microstructure as well as the properties of chitosan films, which is essential for their usage in food industry.

Molecular interactions in gelatin/chitosan composite films.

Gelatin and chitosan were mixed at different mass ratios in solution forms, and the rheological properties of these film-forming solutions, upon cooling, were studied. The results indicate that the significant interactions between gelatin and chitosan promote the formation of multiple complexes, reflected by an increase in the storage modulus of gelatin solution. Furthermore, these molecular interactions hinder the formation of gelatin networks, consequently decreasing the storage modulus of polymer gels. Both hydrogen bonds and electrostatic interactions are formed between gelatin and chitosan, as evidenced by the shift of the amide-II bands of polymers. X-ray patterns of composite films indicate that the contents of triple helices decrease with increasing chitosan content. Only one glass transition temperature (Tg) was observed in composite films with different composition ratios, and it decreases gradually with an increase in chitosan proportion, indicating that gelatin and chitosan have good miscibility and form a wide range of blends.