The hydrolyzed peach gum polysaccharide (HPGP) prepared at acidic condition is investigated as an anionic polyelectrolyte for the first time. A hydrolysis mechanism is proposed by monitoring the hydrolysis efficiency and morphological change of crude peach gum, and the intrinsic viscosity of resulted HPGP as a function of hydrolysis time. Fourier transform infrared (FTIR) spectroscopy and ζ-potential measurements reveal that HPGP with multiple carboxylic groups is negatively charged in water in the pH range 3–11. The HPGP exhibits remarkable pH and ionic strength responsiveness, as proven by dynamic light scattering (DLS) and atomic force microscopy (AFM) measurements. Moreover, the layer-by-layer (LbL) self-assembly experiments further confirmed that the HPGP can be utilized as an anionic polyelectrolyte . Considering the facile availability, favorable compatibility and intriguing functionality of HPGP, this study opens up enormous opportunities for the large-scale utilization of peach gum resource.
Hu Qu,Bizhou Lin,Liwen He,Xiaorong Fan,Yi Zhou,Yilin Chen,Bifen Gao
TaWO 6 nanosheet was assembled into multilayer films by a layer-by-layer deposition technology with polyethylenimine as the linker. UV–vis absorption spectra in the assembly process showed a linear enhancement of absorbance at 238 nm per deposition cycle, indicating the successful formation of multilayer composite films, which were converted into polymer-free films by the heat treatment at 400 °C for 2 h. The bandgap energy and flatband potential of TaWO 6 nanosheet were estimated to be 3.48 eV and −0.79 V vs. Ag/AgCl, respectively. The photoelectrocatalytic degradation of Rhodamine B with the TaWO 6 nanosheet electrodes demonstrated that both the oxygen anionic radicals and the dye cationic radical are essential to mineralize the dye under visible-light-driven photocatalytic conditions. It is the first time to investigate the mechanism of photoelectrocatalysis of TaWO 6 nanosheet electrode.
To confer cellulose fibers antimicrobial and antioxidant activities, chitosan (CS)/lignosulfonates (LS) multilayers were constructed on fibers surfaces through layer-by-layer deposition technique. The formation of CS/LS multilayers on cellulose fibers surfaces was verified by X-ray photoelectron spectroscopy (XPS) and zeta potential measurement. The surface morphologies of CS/LS multilayers on fibers surfaces were observed by atomic force microscopy (AFM). The results showed that characteristic element (i.e. N and S element) content increased with increasing bilayers number, the surface LS content increased linearly as a function of bilayers. Zeta potential of modified fibers was inversed after deposition of each layer. AFM phase images indicated that the cellulose microfibrils on fibers surfaces were gradually covered by granular LS aggregate. The antimicrobial testing results demonstrated that CS/LS multilayers modified fibers with CS in the outermost layer exhibited higher antimicrobial activity against Escherichia coli . The antioxidant testing results showed that antioxidant activity of CS/LS multilayers modified fibers was better than that of original fibers under the same oxidation conditions.
A biocompatible fiber-optic pH sensor based on Fresnel reflection technique and a sensing coating is presented. Sodium alginate and polyethylenimine are alternatively deposited on the sensing fiber end to form the sensing coating via a layer-by-layer electrostatic self-assembly technique. An optical switch is added to the measurement system for the convenience of fast calibration. A linear, monotonic and fast response in a large pH range (from pH 5.87 to pH 10.55) is obtained with the resolution of 0.01 pH unit. The sensitivity of the pH sensor is 0.018 R.I.U/pH. It is not influenced by fluctuations of light source.
危险品化学品经营许可证（带存储）