This study focuses on the development and characterization of a series of six new dansyl derivatives (L1 to L6) and their integration into PMMA polymers for application in environmental sensing. The photophysical properties of these derivatives were extensively studied in various solvents and in solid state. A remarkable positive solvatochromic effect was observed, indicating their potential in microenvironmental polarity assessment. The dansyl derivatives demonstrated selective sensing capabilities for Cu2+ and Hg2+ metal ions, with the formation of mononuclear species. Additionally, their acid-base responsive nature was explored, revealing potential for pH-sensitive applications. The incorporation of these derivatives into PMMA polymers resulted in acid-base sensitive materials suitable for environmental monitoring, particularly in detecting hazardous gases and changes in pH levels. This integration overcomes the solubility limitations of dansyl compounds and extends their applicability in diverse sensing scenarios.

We recently developed a novel hyperspectral excitation-resolved near-infrared fluorescence imaging system (HER-NIRF) based on a continuous-wave wavelength-swept laser. In this study, this technique is applied for measuring the distribution of the therapeutic agent dimethyl sulfoxide (DMSO) by utilizing solvatochromic shift in the spectral profile of albumin-bound Indocyanine green (ICG). Using wide-field imaging in turbid media, complex dynamics of albumin-bound ICG is measured in mixtures of dimethyl sulfoxide (DMSO) and water. Phantom experiments are conducted to evaluate the performance of the HER-NIRF system. The results show that the distribution of DMSO can be visualized in the wide-field reflection geometry. One of the main purposes of the DMSO is to act as a carrier for other drugs, enhancing their effects by facilitating skin penetration. Understanding solubility and permeability of drugs in vivo is very important in drug discovery and development. Hence, this HER-NIRF technique has a great potential to advance the utilization of the therapeutic agent DMSO by mapping its distribution via solvatochromic shift of ICG. By customizing the operational wavelength range, this system can be applied to any other fluorophores in the near infrared region and utilized for a wide variety of drug delivery studies.

After a survey on polymer plasticization theories and conventional criteria to evaluate polymer-plasticizer compatibility through the solubility parameter, an attempt to create a polymer-plasticizers polarity scale through solvatochromic dyes has been made. Since the Reichardt’s ET(30) dye is insoluble in rubber hydrocarbon polymers like polyisoprene, polybutadiene and styrene-butadiene copolymers and is not also useful for the evaluation of the hydrocarbons and ester plasticizers, the Nile Red solvatochromic dye was instead used extensively and successfully for this class of compounds. A total of 53 different compounds were evaluated with the Nile Red dye and wherever possible also with the ET(33) Reichardt’s dye. A very good correlation was then found between the Nile Red scale E(NR) and the Reichardt’s ET(30) scale for this class of compounds focusing on diene rubbers and their typical hydrocarbons and new esters plasticizers. Furthermore, the E(NR) scale shows also a reasonable correlation with the total solubility parameter calculated according to the Van Krevelen method. Based on the above results, some conclusion was made about the compatibility between the diene rubbers and the conventional plasticizers as well as some new and green plasticizer proposed for the rubber compounds.