Color-switchable hybrid dots/hydroxyethyl cellulose ink for anti-counterfeiting applications.

Many anti-counterfeiting inks have been explored recently, most of them are commonly involved in weak fastness, high cost and long-term toxicity, impeding their real-life applications. Herein, an environment-friendly and inexpensive anti-counterfeiting ink with excellent fastness is reported. The untifake ink is developed by combining hybrid dots (silicon/carbon) with hydroxyethyl cellulose (HEC) binder. Interestingly, the HEC binder can effectively prevent from aggregation-induced quenching of hybrid dots. Subsequently, the customized patterns are successfully transferred onto different surfaces of various substrates including cotton fabric, cellulosic paper, glass, metal, silicon wafer and PET film, using the as-prepared ink by screen-printing technique, exhibiting that the hybrid dots/HEC ink possesses widespread practicability. Notably, fluorescent color of these patterns can be switchable by adjusting environmental pH-value, further imparting the as-prepared ink with excellent covert performance. This new fluorescent hybrid dots/HEC ink will be promising candidates for high-level anti-counterfeiting applications including food packaging, apparel and documents.

Processing and Characterization of Polymer-Based Far-Infrared Composite Materials.

Polymer-based far-infrared radiation (FIR) composite materials are receiving increasing attention due to their significant influence on bioactivity. This study reports the processing of FIR composite films based on a polymer matrix and FIR radiation ceramic powders, as well as the characterization of the FIR composites. Field-emission scanning electron microscopy (SEM) and laser particle size analysis were employed to analyze the characteristic of the ceramic powders. The average size, dispersity, and specific surface area of the ceramic powders were 2602 nm, 0.97961, and 0.76 m2/g, respectively. The results show that the FIR ceramic powders used in the composite films had excellent far-infrared emissive performance. Moreover, by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TG), it was indicated that the thermal performance and mechanical properties of the composite films were significantly influenced (p < 0.05) by the addition of the FIR ceramic powders. Specifically, the elongation at break decreased from 333 mm to 201 mm with the increase in FIR ceramic powders. Meanwhile, the contact angle and light transmittance were also changed by the addition of the FIR ceramic powders. Furthermore, the two different processing methods had great influence on the properties of the composite films. Moreover, the composite blown films with 1.5% FIR ceramic powders showed the highest far-infrared emissivity, which was 0.924.

Properties and Applications of High Emissivity Composite Films Based on Far-Infrared Ceramic Powder.

Polymer matrix composite materials that can emit radiation in the far-infrared region of the spectrum are receiving increasing attention due to their ability to significantly influence biological processes. This study reports on the far-infrared emissivity property of composite films based on far-infrared ceramic powder. X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray powder diffractometry were used to evaluate the physical properties of the ceramic powder. The ceramic powder was found to be rich in aluminum oxide, titanium oxide, and silicon oxide, which demonstrate high far-infrared emissivity. In addition, the micromorphology, mechanical performance, dynamic mechanical properties, and far-infrared emissivity of the composite were analyzed to evaluate their suitability for strawberry storage. The mechanical properties of the far-infrared radiation ceramic (cFIR) composite films were not significantly influenced (p ≥ 0.05) by the addition of the ceramic powder. However, the dynamic mechanical analysis (DMA) properties of the cFIR composite films, including a reduction in damping and shock absorption performance, were significant influenced by the addition of the ceramic powder. Moreover, the cFIR composite films showed high far-infrared emissivity, which has the capability of prolonging the storage life of strawberries. This research demonstrates that cFIR composite films are promising for future applications.

Extraction, characterization and antioxidant activities of polysaccharides of Chuanminshen violaceum.

A single factor experiment and Box-Behnken design were applied to optimize the microwave-assisted extraction (MAE) of Chuanminshen violaceum polysaccharides (CVPs). The CVPs yield was 34.59 ± 0.51%, which was in accordance with the predicted value of 35.54%, under the following optimum conditions: microwave power of 466 W, extraction temperature of 64.5 °C, extraction time of 15 min, and water-raw material ratio of 40 mL/g. Two CVPs fractions (CVPs-I and CVPs-II) were obtained via stepwise ethanol precipitation. CVPs-II was further purified using DEAE cellulose-52 chromatography to obtain the major fraction of CVPs-IIa. Fourier transform infrared spectroscopy (FTIR) and GC-MS analysis revealed that crude CVPs, CVPs-I, and CVPs-II were neutral polysaccharides and were mainly composed of glucose and galactose. The molecular weights of CVPs-I and CVPs-IIa were 233.69 and 11.02 kDa, respectively. Furthermore, all samples exhibited certain antioxidant activity or reducing power to scavenge the DPPH and ABTS radicals, among which CVPs-II was the strongest. In conclusion, MAE is an efficient method for extracting CVPs of C. violaceum, and this plant root has the potential to be explored as a source of natural antioxidants.

Identification of the geographical origins of pomelos using multielement fingerprinting.

Eighty pomelo samples and 80 soil samples were examined using a multielement component test to predict the geographical origins of pomelos produced in 4 regions (Sichuan, Chongqing, Fujian, and Guangxi Provinces) of China. The concentrations of 8 elements were determined by atomic absorption spectrometry. Ca, K, and Na were the most abundant elements. Principal component analysis (PCA) and linear discriminant analysis (LDA) were applied to reduce the dimensionality of the multielement data from 8 to 2 while retaining the highest possible variance. Using PCA and LDA, 69.66% and 91.30%, respectively, of the pomelo origins were classified correctly using multielement variables, along with 67.06% and 83.40% for soil multielement analysis. Results indicated that the LDA method was more effective for geographical origin classification than PCA. The results of the multielement component test demonstrated its capability to screen pomelo origins rapidly.