Preparation and characterization of cellulose paper/polypyrrole/bromophenol blue composites for disposable optical sensors

摘要

This manuscript describes a novel approach for the preparation of composites based on cellulose paper (CP) modified with polypyrrole (PPy) and bromophenol blue (BPB) (CP/PPy/BPB). Cellulose fibers are suitable for uniformly retaining the polymer in its doped form, once BPB can be used as a negatively charged dye. The CP/PPy/BPB composites were characterized by Raman Spectroscopy, Scanning Electron Microscopy, Spectroscopy and Dispersive Energy, and X-ray Diffraction. After characterization, they were studied for the quantification of pH and ammonia by diffuse reflectance spectroscopy. Under varying pH, different colors were verified, which ranged from yellow to blue, and an optical response for ammonia at concentrations as high as 25 ppm. The replacement of BPB by bromothymol blue (BTB) did not produce efficient color transitions and showed no sensitivity to changes in pH and ammonia concentration.