Incorporating fluorescent nanomaterials in organically modified sol–gel materials – creating single composite optical pH sensors

Abstract

Optical sensors hold the promise of providing the coupling between the tangible and the digital world that we are currently experiencing with physical sensors.

Multicolor Polystyrene Nanosensors for the Monitoring of Acidic, Neutral, and Basic pH Values and Cellular Uptake Studies

“…Such measurements commonly utilize molecular and nanoscale fluorescent probes and sensors which undergo target-specific changes of the intensity and/or spectral position of their absorption and/or fluorescence or changes in their fluorescence lifetime and emission anisotropy. Targets that are fluorometrically detectable with the aid of such probes and sensors include environment parameters like temperature, viscosity, and polarity; gases like oxygen; , and ionic analytes such as protons (pH), , metal ions, , and anions; as well as neutral species like certain enzymes, proteins, and carbohydrates such as glucose. , …”

On the Use of Polymer-Based Composites for the Creation of Optical Sensors: A Review

“…The development of optical sensors is often faced with a situation where the matrix material must satisfy a number of specific requirements that may contradict or interfere with each other. One of the most common is that the material must provide porosity for the transfer of the analyte, but at the same time immobilize the indicator dye [ 161 ]. Particularly in the case of a pH sensor, this means that matrix must be hydrophilic to measure in water, while the hydrophobic dye containers must be provided to ensure a high signal intensity.…”

α‐Al2O3/Organo‐Modified Silica pH Sensing Film with High Alkali Resistance and Sensitivity

“…[12] Wei Li et al formed a pH coating on the surface of the optical fiber by dipping-coating the precursor ethyl orthosilicate (TEOS) and pH-sensitive indicator, and it was able to test solutions ranging from pH 1-13 with good linear response, high sensitivity and fast response time, but poor durability, lasting only 2-3 days. [13] However, the above pHsensing films have short-term stability due to photobleaching, [4,14] and they are hard to maintain a certain shape under pressure or upon exposure to harsh conditions (extreme acidic or basic conditions), thus limiting their application in industrial and environmental fields, which often require long-term, online monitoring of pH changes in samples. Therefore, there is an urgent need for pH sensing films with long-term stability and high resistance to acid and alkali corrosion.…”