Luminescent MOF polymer mixed matrix membranes for humidity sensing in real status analysis

Abstract

Humidity sensing properties of luminescent metal–organic framework (MOF) polymer mixed-matrix membranes (MMMs) ³_∞[Ba_0.98Eu_0.02(Im)₂]@PSF (Im = imidazolate, PSF = polysulfone Ultrason® S), ³_∞[Sr_0.90Eu_0.10(Im)₂]@PSF, and ³_∞[Ce(Im)₃ImH]·ImH@PSF were investigated. MMMs show superior properties compared to bulk MOFs especially in stability, handling and long-term monitoring. In order to evaluate these films for such real status analyses, both their sensitivity and stability were determined and compared to bulk MOFs. Therefore, the progress of the humidity induced luminescence intensity quenching of the MMMs and the corresponding bulk substances was investigated for several pre-set relative humidities at room temperature. The MMMs show distinct and diverse luminescence loss and sensitivity rendering the monitoring of a very low relative humidity of only 2% accessible.