Compensation for the influence of temperature and humidity on oxygen diffusion in a reactive polymer matrix
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. It can be used in packaging, sensors, and biotechnology applications. Since the oxygen diffusion coefficient in the PVA matrix strongly depends on temperature and humidity, two different approaches were developed within this work to compensate for these two effects. To compensate for faster oxygen diffusion at higher temperatures, iron particles were added to the PVA matrix, resulting in a novel PVA/iron composite matrix. Adding silicone particles allows compensating the influence of humidity. Both temperature and humidity compensation were modeled using the finite-element method in good accordance with the experimental data. This allows tuning the sensor for application at different conditions of temperature and humidity and therewith in different environments.