Smartphone-based colorimetric determination of some physicochemical properties of polyaniline on flexible cellulose substrate

Polymer-based materials are of high potential for application as active materials in contemporary electronic gadgets. The functionality of such materials is highly dependent on their oxidation state and requires fine control during their synthesis. Owing to that, we have designed a cost-effective, simple, portable, system for calibration and the detection of the optical and electrical properties of polyaniline loaded on a paper substrate using a smartphone-based colorimetric sensor. The vapor phase polymerization technique was adopted for preparing polyaniline. Colorimetric measurements of polyaniline-loaded papers were achieved by estimating the hue, saturation and value (HSV) color parameter values using an open-source smartphone application called "Color Grab (Color Detection)" during synthesis at different time intervals. The proposed sensor relies on the principle of Beer-Lambert law. The rear camera of the smartphone acts as a sensor and captures the light signal from the samples and provides information to the colorimetric app. The colorimetric results showed a promising correlation between the color parameter values with their electrical properties. The optical absorbance results of all polyaniline-loaded papers are also in accordance with the H parameter values. The proposed sensor can be used as a portable smartphone-based point-of-care testing kit to bring in-situ control during synthesis.HighlightsConducting polymer on flexible cellulose substrate.Smartphone-based visual colorimetric sensor.Biodegradable and environment-friendly electronic material.Variation of electrical properties in terms of hue values.Cheap, portable sensor for point-of-care testing. Measurement of colorimetric parameter and its correlation with optical and electrical properties of PANI.image