The use of optical sensors for oxygen measurement is becoming more important because of their capability for low-cost and direct measurement,but as yet,little has been reported about their long-term performance.Phosph...The use of optical sensors for oxygen measurement is becoming more important because of their capability for low-cost and direct measurement,but as yet,little has been reported about their long-term performance.Phosphorescent sensors based on platinum octaethylporphyrin(PtOEP)embedded in polymer matrices tend to degrade with time.To reduce the rate of degradation,sensor films were fabricated and then coated with a layer of polydimethylsiloxane(PDMS)and tested in a six-month study.The PDMS-coated sensors showed an average degradation rate of〜0.073%/day,compared to〜0.18%/day for uncoated sensors.Titania beads were also incorporated into the films to increase light scattering and improve the response;these beads compensated to some degree for the absorption due to the PDMS films.The films with titania beads improved the response significantly(about 40%)compared to the films without titania beads.Incorporation of titania beads also moderately improved the aging characteristics.展开更多
Four sensing membranes based on fluorescence quenching were prepared by sol-gel method and CA membrane method, and the Ru(Ⅱ) complexes, Ru( bpy)3 Cl2 and Ru(phen)3 Cl2 , were used as the indicators . The results indi...Four sensing membranes based on fluorescence quenching were prepared by sol-gel method and CA membrane method, and the Ru(Ⅱ) complexes, Ru( bpy)3 Cl2 and Ru(phen)3 Cl2 , were used as the indicators . The results indicate that the volume fraction of oxygen o2 have a linear relationship in large scale with tan0/tanfor all of the sensing membranes. They have super properties such as excellent limit of detection ,fast response time and good reproducibility. The stability of the sensing membranes made by sol-gel method is better than those by CA membranes, but the uniformity of the latter is better than that of the former.展开更多
Modified sensing membranes based on fluorescence quenching were prepared by the sol-gel method,using formamide as the drying control chemical additive,tetraethoxysilane as the main material,Ru(phen) 3Cl 2 as the ind...Modified sensing membranes based on fluorescence quenching were prepared by the sol-gel method,using formamide as the drying control chemical additive,tetraethoxysilane as the main material,Ru(phen) 3Cl 2 as the indicator.The membrane with the optimum thickness of 20-50μm is uniform and crack-free,in which the indicator has a very small leaking rate.The membrane is immersed in water for 50h,the membrane sensing parameter M decreases by less than 5%.The fiber optic oxygen sensor with the sensing membrane has a detection limit of 5×10 -6M(ppm),a response time of less than 30s,excellent reproducibility and stability.展开更多
文摘The use of optical sensors for oxygen measurement is becoming more important because of their capability for low-cost and direct measurement,but as yet,little has been reported about their long-term performance.Phosphorescent sensors based on platinum octaethylporphyrin(PtOEP)embedded in polymer matrices tend to degrade with time.To reduce the rate of degradation,sensor films were fabricated and then coated with a layer of polydimethylsiloxane(PDMS)and tested in a six-month study.The PDMS-coated sensors showed an average degradation rate of〜0.073%/day,compared to〜0.18%/day for uncoated sensors.Titania beads were also incorporated into the films to increase light scattering and improve the response;these beads compensated to some degree for the absorption due to the PDMS films.The films with titania beads improved the response significantly(about 40%)compared to the films without titania beads.Incorporation of titania beads also moderately improved the aging characteristics.
基金Funded by The Key Scientific Project Foundation of Hubei Province (No.2001AA101A02) and Natural Science Foundation of Hubei Province (No.2001ABB074)
文摘Four sensing membranes based on fluorescence quenching were prepared by sol-gel method and CA membrane method, and the Ru(Ⅱ) complexes, Ru( bpy)3 Cl2 and Ru(phen)3 Cl2 , were used as the indicators . The results indicate that the volume fraction of oxygen o2 have a linear relationship in large scale with tan0/tanfor all of the sensing membranes. They have super properties such as excellent limit of detection ,fast response time and good reproducibility. The stability of the sensing membranes made by sol-gel method is better than those by CA membranes, but the uniformity of the latter is better than that of the former.
文摘Modified sensing membranes based on fluorescence quenching were prepared by the sol-gel method,using formamide as the drying control chemical additive,tetraethoxysilane as the main material,Ru(phen) 3Cl 2 as the indicator.The membrane with the optimum thickness of 20-50μm is uniform and crack-free,in which the indicator has a very small leaking rate.The membrane is immersed in water for 50h,the membrane sensing parameter M decreases by less than 5%.The fiber optic oxygen sensor with the sensing membrane has a detection limit of 5×10 -6M(ppm),a response time of less than 30s,excellent reproducibility and stability.
