Halochromic Polystyrene Nanofibers Obtained by Solution Blow Spinning for Wine pH Sensing

Abstract

Colorimetric sensors developed by the solution blow spinning (SBS) technique have a rapid response to a variation in different physicochemical properties. In this study, polystyrene nanofibrous (PSNF) mats containing the bromothymol blue (BTB) indicator were obtained by SBS for the pH sensing of wine sample. The incorporation of the indicator did not promote changes in fiber diameter but led to the appearance of beads, allowing for the encapsulation of BTB. The halochromic property of BTB was retained in the PSNF material, and the migration tests showed that the indicator mats presented values below the maximum acceptable limit (10 mg dm−2) established by EU Commission Regulation No. 10/2011 for foods with an alcohol content up to 20%. The present study opens the possibility of applying nanostructured materials to innovative food packaging which, through nanosensory zones, change color as a function of the food pH.

Halochromic Polymer Nanosensors for Simple Visual Detection of Local pH in Coatings

“…The change of pH value on metal surfaces is important information that can be retrieved from smart coatings for the early detection of corrosion. , Determining the pH during corrosion is important for designing pH-responsive materials which can release corrosion inhibitors , or healing agents . Halochromic fibers were loaded with pH-indicator dyes for monitoring pH variations in various liquids − or the presence of acid gas . In order to detect the local pH at surfaces, other strategies are needed.…”

A colour indicator film based on bromothymol blue/poly‐L‐lactic acid/polyvinylpyrrolidone for detecting bacteria

“…The bands at 1348, 1157 and 1039 cm À1 , which showed the ÀSO 3 functional group and the peaks at 877 and 798 cm À1 were from the symmetric and asymmetric S-O-C stretching vibration. 19,20 The bands at 651 cm À1 resulted from the stretching of C-Br. 21 In the FTIR spectrum of PVP shown in Figure 2B, one of the peaks of the PVP was observed at 3425 cm À1 , which was assigned for O-H stretching.…”

“…26 Therefore, this result suggested that a minimum concentration of colour indicator film incorporation may have occurred due to weak intermolecular interactions between the hydrophobic groups of BTB and the hydrophobic surface of the polymer, so the low concentration of BTB resulted in the no absence of bands associated with it in the spectra of the BTB/PLLA/ PVP fibres. 19…”

Solution Blow Spinning (SBS): A Promising Spinning System for Submicron/Nanofibre Production

“…Production of ceramic nanofibres such as TiO 2 nanofibres was performed through the SBS system followed by calcination [15]. Polystyrene nanofibrous (PSNF) mats containing the bromothymol blue (BTB) indicator for sensing the pH of wine was made by this spinning principle [93]. Conductive nonwoven fabric has successfully been developed and applied in smart textronics to detect various biosignals [94].…”