Magnetite submicrospheres with an average size range of 90–490 nm were obtained by a facile polyol process. The effects of reaction conditions on the morphology and static magnetism of magnetite submicrospheres were studied when the reaction time, the concentration of component, and the types of the solvent or surfactant changed. The average size of primary crystals was controlled by changing the concentration of surfactant thus the superparamagnetism was obtained, meanwhile the average size of secondary clusters was tuned by changing the concentration of ferrous precursor FeCl 3 ·6H 2 O. The ratio of ethylene glycol and diethylene glycol , the concentration of NaAC, and the reaction time all exhibited novel effects on the morphology of magnetite submicrospheres facilitating our understanding about the synthesis mechanism. The synthesized magnetite submicrospheres were successfully used for photonic crystal .
In this work, hydrogel photonic crystal beads with inverse opal structure are generated on a well-controlled microfluidic chip device. An online droplet drying method and templating technique are integrated into the producing process. This process results in the silica nanoparticles in the droplets self-assembled into spherical photonic crystals with narrow stop bands and identical structural colours, which is the ideal template for fabricating inverse opal hydrogel beads. The effects of acrylic acid (AA) concentration, water dosage and buffer pH on the equilibrium swelling of inverse opal hydrogel are discussed. In the concentration of AA (3%) and water (31%), the inverse opal hydrogel beads show wide sensing range and rapid response (less than 30 s) to pH variation. Overall, the inverse opal hydrogels as pH sensors show homogeneous structural colour changes due to the spherical 3D structure. The present characterization of quite mechanically robust and good reproducibility for the spherical pH sensor may have promise application in advanced optical devices.
Lu Li,Xugang Dong,Zhanfang Liu,Juan Wei,Jingru Li,Hong Zhou,Jun Zhu,Xinwei Shi
In this study, a visual and ultrasensitive method for the determination of trace mercury ions in water was developed based on the high efficiency of urease catalysis and pH-sensitive inverse opal polymeric photonic crystals (IOPPCs). Mercury ions can inhibit urea hydrolysis and suppress the production of ammonium and bicarbonate ions in the solution, resulting in the redshift of IOPPCs. Therefore, the redshift of IOPPCs Bragg diffraction is directly related to the concentration of mercury ions. Meanwhile, the color of IOPPCs varied significantly with the shift of the Bragg diffraction wavelength, thus achieving the visual semi-quantitative detection of mercury ions by the naked eye. The minimum detection concentration of this method is 5 × 10 −16 g/L, which is much lower than the maximum contaminant level for the safe drinking of water (2 × 10 −6 g/L) recommended by the environmental protection agency (EPA), USA. In addition, this is a simple and quick method for effective on-site detection of mercury ions, which shows a great promise in emergency leakage monitoring and control.
In order to achieve the coloration and hydrophobicity of cotton fabrics through one-step processing, this study utilized a vertical deposition method to fabricate polystyrene (PSt) photonic crystals on cotton fabrics. The morphological changes of cotton fabrics, the arrangement of photonic crystals and structural color effects, and the changes of hydrophobicity of cotton fabrics were investigated. Moreover, the possible mechanism of hydrophobicity was proposed. The results shows that the original gaps existed between adjacent fibers of cotton fabrics are obviously filled by the three-dimensional photonic crystals after the vertical deposition, the resultant cotton fabrics presented bright and iridescent structural colors and strong hydrophobicity. Specifically, a kind of multi-layered structure of water droplets-photonic crystal layers-fabrics was essentially presented, and the strong hydrophobicity was due to the PSt microspheres that made up the photonic crystals itself had good hydrophobicity and the own structure of photonic crystals was rough.
危险品化学品经营许可证（带存储）