摘要
Colloidal photonic crystals(CPCs)have attracted significant attention owing to their ability to enhance fluorescence.However,there has been limited research on thermosresponsive CPCs of fluorescence enhancement for metal ion detection.In this study,poly(N-isopropylacrylamide-co-6-acrylamidopicolinic acid)/europium(P(NIPAM-6 APA)/Eu^(3+),PNA/Eu^(3+))nanogels were synthesized and characterized for their structure and properties.PNA nanogels were first prepared via emulsion precipitation polymerization of NIPAM and 6 APA,followed by coordination with europium nitrate hexahydrate to form fluorescent PNA/Eu^(3+)nanogels,which exhibit red emission due to interactions between 6 APA with Eu^(3+).When the reflection peak(610 nm)of the CPC overlaps with the emission peak(614 nm),the fluorescence intensity is increased by more than 4.2 fold compared with that of the control sample without CPC.Owing to the fluorescence enhancement,the CPC exhibits excellent linear detection for Fe^(3+)ions within the range of 0-50μmol/L,with a detection limit of 0.35μmol/L,and is successfully applied in urine samples with good recovery.Fe^(3+)ions can be recovered from the CPC by ethylenediaminetetraacetic acid(EDTA),indicating the reversibility of the CPC-based sensor.Furthermore,to develop high-performance anti-counterfeiting materials,the PNA/PAM/Eu^(3+)fluorescent hydrogels were fabricated by incorporating polyacrylamide(PAM)into the PNA/Eu^(3+)network through polymerization of acrylamide(AM).These hydrogels exhibit UV-dependent patterns for anti-counterfeiting and reversible fluorescence quenching with Fe^(3+),and logic gate operations for information encoding.These findings highlight the potential applications of the enhanced fluorescent CPC materials for both Fe^(3+)ion detection and anticounterfeiting applications,showing an innovative strategy for combining fluorescence enhancement with logical operations in smart sensing materials.
基金
Project supported by the National Natural Science Foundation of China(52173157)
the Fundamental Research Funds for the Central Universities(2232022A-07)。
