Fluorination physicochemical effects

This chapter presents the state of the art of the use of highly fluorinated liquids in ophthalmology and perspectives of future applications in the eye. In different medical disciplines, the characteristics of these fluids are directly used, like in the case of ocular endotamponades in ophthalmology, of gas carriers in liquid ventilation, or of preservation and transport media in transplantation medicine [1-3]. For these applications, the highly fluorinated liquids are used in a purified form or as mixtures. The intended effect is created by the physicochemical characteristics themselves. The extraordinary behaviour of the fluorocarbon liquids (FCLs) requires specialised biocompatibility testing, adjusted to this class of components. 

The uncommon structural artemisinin framework, and the well-known difficulty in selectively introducing a fluorinated motif into a molecule, faced us with numerous chemical challenges. The evaluation of the effects of fluorine on physicochemical and antima-larial properties is reported. These data and preclinical data of lead compounds are encouraging, with strong and prolonged antimalarial activity of fluoro-artemisinins. 

This section discusses how the fluorine atom influences the physical and physicochemical properties of organic fluorine compounds. One of the most important factors for a better understanding of such properties would be the low electronic polarizability (refractive index) of the molecules. Of course, we cannot disregard other effects such as the strong electron-withdrawing effect and stiff nature of the perfluoroalkyl moiety. 

Biological Properties of Fluorinated Imidazoles The importance of the imidazole ring in biological structure and function combined with the profound effects on physicochemical properties that result from fluorine substitution combine to make fluorinated imidazoles a class of compounds with a wide range of biological... 

The practical applications of fluoropolymer membranes especially in the areas of purification and separation related to potable water production, wastewater treatment and bioprocessing, have been limited to some extent by their hydrophobic and inert surface properties. Among the different modification techniques, graft copolymerization of hydrophilic monomers, or inimers for further surface reactions, from fiuoropolymers has been useful and effective in improving the physicochemical properties of the parent fluoropolymer with minimum alteration of their desirable bulk properties. Apart from fiilly fluorinated polymers, most of the partially fluorinated polymers can dissolve in polar organic solvents, such as Ai,Ai-dimethylformamide (DMF), A,A-dimethylacetamide (DMAc), NMP, and dimethyl sulfoxide (DMSO), but are insoluble in water, alcohols, and hydrocarbons. 

Moreover, the best analytical procedures available have failed to reveal an increase in the fluorine content of topically treated teeth, although most of the studies of topical applications of fluoride to tooth surfaces have demonstrated caries-preventive effects. The most likely explanation seems to be that fluorine influences the physical and biochemical properties of teeth and particularly of enamel surfaces in vivo perhaps by the surface absorption of minute amounts of fluorine by the OH-apatite of the enamel with the production of a protective layer of acid-resisting fluorapatite. Studies with radioactive fluorine have shown that enamel, dentine, bone, and OH-apatite absorb fluorine according to the Freundlich adsorption isotherm.That physicochemical changes do occur which confer acid-... 

This section seeks to report the preparation and characterization of PEMs based on partially fluorinated aromatic polymers. In the past few decades, attention has focused on the preparation of new fluorinated monomers and aromatic fluoropolymers. This topic was recently reviewed [70], summarizing the characteristic effects of the aromatic group on the physicochemical properties (e.g., Tg and the thermostability of the obtained polymers). 

---