查看更多>>摘要：Herein, a multicolor fluorescence sensor with two emission peaks at 445 nm (F445) and 560 nm (F560) under excitation wavelength of 365 nm was facilely fabricated by hybridizing blue and yellow fluorescence carbon dots (B-CDs and Y-CDs). Cu2+ could selectively coordinate with the aromatic amino groups of the Y-CDs, thus forming the Cu2+-Y-CDs complex through electron pair sharing to efficiently quench the fluorescence of B-CDs by Fo center dot rster resonance energy transfer. Meanwhile, the complex could suppress photoinduced electron transfer thus enhancing the fluorescence of Y-CDs. The unique interrelated opposite responses of the sensor toward Cu2+ could generate a remarkable change in the value of F560/F445 and consequently give rise to more easily distinguishable fluorescent color tonality changes from blue to yellow for colorimetric detection. The sensor possessed a low detection limit of 44.05 nmol L-1 and 169.46 nmol L-1 to recognize Cu2+ by the ratiometric fluorescent and colorimetric detection, respectively. Recoveries of 96.8-105.9% (RSD <3.8%) and 94.4-108.5% (RSD <7.7%) were respectively obtained in spiked samples by the ratiometric fluorescent and colorimetric detection, indicating their promising potentials to quick pre-warning of Cu2+ for ensuring food safety and improving public health.
查看更多>>摘要：It is well-known that carbon fiber (CF) cannot be colored by traditional dyeing methods due to the strong inertness of fiber surface. With the increasing demand of consumers for fashion, colorful and diverse CF have attracted extensive attention. In this paper, inspired by the structural colors in nature, structural coloration of CF substrates by rapidly constructing photonic crystals (PCs) with structural colors was realized. The poly (styrenemethacrylic acid) (P(St-MAA)) colloidal microspheres prepared by a soap-free emulsion polymerization were used as building units to construct PCs. The influence of mass fraction of colloidal microspheres and the density of substrates on the structural colors of CF fabrics was investigated. The spraying method was also used to achieve structural color patterns on CF boards. Moreover, in order to improve the durability of structural colors, the resultant CF boards with structural colors were encapsulated with polydimethylsiloxane (PDMS). The results showed that according to Bragg diffraction law, P(St-MAA) colloidal microspheres with particle sizes of 213 nm, 235 nm, 255 nm and 307 nm can present PCs structural colors. When the mass fraction of the colloidal microspheres was 10%, brighter structural colors can be obtained on the CF fabrics with the higher density. The structural colors of patterns on the CF boards were bright and vivid. Furthermore, the colored CF boards encapsulated with PDMS could still maintain bright structural colors after rubbing and rinsing tests. The research will provide new approaches to ecological coloration of CF substrates.
NSTL
Elsevier