Bioinspired structural hydrogels with highly ordered hierarchical orientations by flow-induced alignment of nanofibrils.

Natural structural materials often possess unique combinations of strength and toughness resulting from their complex hierarchical assembly across multiple length scales. However, engineering such well-ordered structures in synthetic materials via a universal and scalable manner still poses a grand challenge. Herein, a simple yet versatile approach is proposed to design hierarchically structured hydrogels by flow-induced alignment of nanofibrils, without high time/energy consumption or cumbersome postprocessing. Highly aligned fibrous configuration and structural densification are successfully achieved in anisotropic hydrogels under ambient conditions, resulting in desired mechanical properties and damage-tolerant architectures, for example, strength of 14 ± 1 MPa, toughness of 154 ± 13 MJ m-3, and fracture energy of 153 ± 8 kJ m-2. Moreover, a hydrogel mesoporous framework can deliver ultra-fast and unidirectional water transport (maximum speed at 65.75 mm s-1), highlighting its potential for water purification. This scalable fabrication explores a promising strategy for developing bioinspired structural hydrogels, facilitating their practical applications in biomedical and engineering fields.

Determination of nitroanilines in hair dye using polymer monolith microextraction coupled with HPLC.

In this study, a novel method for the determination of nitroanilines in hair dye samples has been developed based on poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction (PMME) and high-performance liquid chromatography (HPLC) analysis. Four nitroanilines, p-nitroaniline (PNAL), m-nitroaniline (MNAL), o-nitroaniline (ONAL), and 2,4-dinitroaniline (DNAL), are studied as representatives. To obtain optimum extraction efficiency, several experimental parameters including sample flow rate, sample volume, sample pH, and eluent flow rate have been investigated. Under the optimal experimental conditions, the linear regression coefficients of the standard curves are greater than 0.9990. The limits of detection for p-nitroaniline, m-nitroaniline, o-nitroaniline, and 2,4-dinitroaniline are 0.012, 0.008, 0.018, and 0.005 µg/mL, respectively. The intraday and interday relative standard deviations are less than 3.1 and 5.4%, respectively. The proposed method is simple, rapid, sensitive, and competent when used for the determination of nitroanilines in hair dye samples and the accuracy is assessed through recovery experiments.

Poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction coupled with high performance liquid chromatography for the determination of phthalate esters in cosmetics.

A simple, sensitive, and rapid strategy has been reported in this work which is based on polymer monolith microextraction (PMME) and high performance liquid chromatography (HPLC) for the determination of phthalate esters in cosmetics. A poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolithic capillary column is selected as the extraction medium for PMME. In order to obtain optimum extraction efficiency, the conditions of PMME including sample flow rate, sample volume, sample pH, and eluent flow rate have been investigated. Under the optimum conditions, the limits of detection for dimethyl phthalate (DMP), di-n-butyl phthalate (DBP), dicyclohexyl phthalate (DCHP), and di-n-octyl phthalate (DOP) based three times of standard deviations of blank by seven replicated are in the range of 0.7-3.7 ng mL(-1). The reproducibility of the method is obtained with intra-day and inter-day relative standard deviations less than 3.2% and 7.7%, respectively. The method has been successfully applied to the determination of the four phthalate esters in cosmetics with a recovery range of 81.2-108.8% in all the samples.

Coupling poly-(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction to capillary electrophoresis for the determination of phenols in water samples.

In the present work, a simple, selective, and sensitive method has been proposed for the determination of four phenols (catechol, resorcinol, 2,6-dimethylphenol, and 2,4,6-trinitrophenol) in water samples. The method is based on poly-(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction (PMME) and capillary electrophoresis-ultraviolet (CE-UV) analysis. The operation parameters including sample pH, sample flow rate, sample volume, and eluent flow rate have been studied and optimized. Under the optimal experimental conditions the limits of detection for catechol, resorcinol, 2,6-dimethylphenol, and 2,4,6-trinitrophenol based three times of standard deviations of blank by seven replicates are 0.085, 0.030, 0.159 and 0.006 microg/mL, respectively. The intra-day and inter-day relative standard deviations are less than 5.6% and 5.9%. The proposed method has been successfully applied to the determination of the four phenols in water samples and the accuracy is assessed through recovery experiments.