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

Abstract

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.

A magenta polypyrrole derivatised with Methyl Red azo dye: synthesis and spectroelectrochemical characterisation

“…Similar results were found for Polyaniline (PAni) [59,60] and PPy [60,61] prepared by different methodologies, such as PAni nanocomposites [62], PAni-polyvinyl alcohol composite membranes [63], PAni nanofibers [64] and PPybromophenol blue composites [65], for pH determination in aqueous solutions and/or acid vapours. In such cases the colour variation was from green at pH = 4 through blue at pH = 7 and purple at pH = 12 for PAni [64], and from yellow in acidic medium (pH = 2) to blue in basic medium (pH = 10) for PPy-bromophenol blue composites [65]. The behaviour observed for PPy-bromophenol blue according to the pH variation suggest that the dye (dopant) plays an important role in the optical properties of the PPy films.…”

Differences in the Structural Chemical Composition of the Primary Xylem of Cactaceae: A Topochemical Perspective

“…Xylem is a complex plant tissue formed by cells that carry out different functions (Baucher et al, 2007; Růžička et al, 2015) such as water conduction, support, and storage (Pratt et al, 2007; Brodersen and McElrone, 2013; Lucas et al, 2013). Secondary xylem is the most studied structure mainly in tree species (Danzer et al, 2001; Lupi et al, 2010), industrial pulping processes (Sahin and Arslan, 2008; Reddy et al, 2014), or timber-yielding production (Pawlicka and Waliszewska, 2011).…”

pH-Responsive Dual-Emitting Hydroxypropyl Methylcellulose-Based Material Containing Fluorescein Isothiocyanate and CaAl2O4:Eu2+,Dy3+ Phosphors

“…Accurate sensing and detection for pH change play an important role in the industrial process, medical diagnosis, crop production, life science, environmental monitoring, etc . The existing pH-responsive cellulose-based fluorescent materials containing pyridine polymer, bromomethyl green, and bromophenol blue mainly show the single fluorescence characteristic and a lack of the dual-emitting effect. Fluorescein isothiocyanate (FITC), with the maximum excitation and emission wavelengths of 483 and 535 nm, respectively, is a kind of aromatic conjugated fluorescent dye with a chromogenic group aromatic ring, a heterocyclic structure, and a π-conjugated double bond system.…”