Fluorescent Probes for Sensing Processes in Polymers

Abstract

Fluorescence spectroscopy is an important analytical technique that has been widely used in a variety of applications, such as biomedicine, biology, and science of materials, because it presents some properties which makes it unique, that is, extraordinary sensitivity and selectivity, short delay time (<10(-9) s), and it is neither invasive nor destructive, so it can be used for in situ measurements. Generally, intrinsic fluorescence of many materials, like polymers, is unspecific so it is not useful to analyse their properties or to be correlated to changes in their microenvironment. The incorporation of additives with fluorescent groups would be necessary. When the fluorescence emission of these molecules is sensitive to changes of properties, such as polarity, fluidity, order, molecular mobility, pH, or electric potential, they can be used for detecting such changes in their microenvironment, and they are called fluorescent probes. As long as these probes can follow processes of practical interest, they can be employed as sensors, if the information given by the measure of fluorescence adequately reflects the changes in the system. In addition, a sensor must fulfil some other requirements in order to make them of practical use, the most important being that the material support in which the sensor molecule is inserted. This support should permit a rapid detection of the process and should allow easy processing in a variety of forms. Polymers are well-known systems in which estimation of local parameters are possible by means of fluorimetric techniques. It allows the study of dynamic processes of interest, such as polymerization kinetics and mechanisms, thermal transitions, photodegradation, swelling morphology changes, and so forth.

Study of Water Adsorption in Poly(N-isopropylacrylamide) Thin Films Using Fluorescence Emission of 3-Hydroxyflavone Probes

“…39,40 Fluorescence spectroscopy is a powerful tool for monitoring microscopic changes in polymer systems due to the high sensitivity and selectivity, short response time, and non-destructive nature of the measurement. 41 However, in the case of fluorophores with a single emission band, there are problems such as photobleaching, excitation source instabilities and variations in probe concentration which can make measurements unreliable, particularly in viscous/rigid polymers. [32][33][34][35] One means of overcoming such problems would be through the use of ratiometric fluorophores.…”

Reconstruction by fluorescence imaging of the spatio-temporal evolution of the viscosity field in Hele-Shaw flows

“…For example, they are used in polymer chemistry to study changes in free volume of polymers as a function of polymerization reaction parameters, molecular weight, and crosslinking, [27][28][29][30] in cell physiology to study cell membrane viscosity which is linked to Radial pumping is accomplished with syringe pump. The distance b between the two plates of the Hele-Shaw cell is set to 0.65 mm.…”

Development of efficient processes under flow conditions based on catalysts immobilized onto monolithic supported ionic liquid-like phases

“…This was illustrated by measuring the solvatochromic effects experienced by a fluorescent probe, such as pyrene. The ratio of the intensities for two emission bands of pyrene (I I /I III ) is a classical measurement for the polarity of a given medium [31]. When applied for m-SILLPs-4a-b the I I /I III values were 1.34 and 1.42, respectively, providing an estimation of polarity comparable to that of methanol (I I /I III = 1.33).…”