Time-monitoring sensor based on oxygen diffusion in an indicator/polymer matrix

Compensation for the influence of temperature and humidity on oxygen diffusion in a reactive polymer matrix

“…To achieve the desired water mass fraction in the final PVA films, they were equilibrated at RH and temperature of interest (see Table 1) for at least 24 h. The correlation between the water mass fraction in PVA on the one hand and RH and temperature in the surrounding atmosphere on the other hand was already described in Jack et al (2011) and Marek et al (2013). The temperatures, RH and resulting water mass fractions in the investigated PVA films are summarized in Table 1.…”

“…To remove the oxygen from the PVA composite matrix before the experiments (see activation of the films in Marek et al, 2013), the films were finally irradiated by UV (ultraviolet) light using an Osram Ultra-Vitalux 300 W lamp under a nitrogen atmosphere until the films turned yellow. After the activation the yellow-colored films contain no oxygen as already shown in Marek et al (2013).…”

“…Moreover, the permeation and diffusion of oxygen into polymers are mainly determined by their water content (directly related to relative humidity -RH; Jack et al, 2011) and by temperature. For numerous applications, such as for time monitoring (Marek et al, 2013) based on oxygen diffusion, this leads to incorrect outcomes as e.g., oxygen diffusion is increased with increasing temperature and water content.…”

“…In this work new compensation approaches have been developed and applied to compensate for the effect of temperature and humidity on oxygen diffusion in oxygen sensors (e.g., Marek et al, 2013). For their applications such as in the packaging or sensor technology, this dependency is undesirable.…”

“…In a previous work (Marek et al, 2013) a time-monitoring oxygen sensor was proposed. This sensor is based on a diffusion-controlled oxygen reaction of the indicator system methylene blue (MB)/leuco methylene blue (LMB) and riboflavin embedded in a water-loaded poly(vinyl alcohol) (PVA) matrix.…”