## 3 Fluorine Materials and Polymers  
For over a decade, a major synthetic target in fluorine material science has been the preparation of hydrophobic and superhydrophobic surfaces that are suitable for non-stick self-cleaning and anticorrosion applications. There is great interest in developing practical methods to generate such surfaces. [PERSON] and coworkers [2] in their paper on _Fluorine Based Superhydrophobic Coatings,_ synthesized monodispersive silica nanoparticles of \(\sim\)120 nm diameter via the Stober process that were further functionalized using fluoroalkylsilane (FAS-17) molecules to incorporate the fluorinated groups with the silica nanoparticles in an ethanolic solution. The synthesized fluorinated silica nanoparticles were spin coated on flat aluminum alloy, silicon and glass substrates. The water contact angles and surface roughness increased with the number of spin-coated thin films layers. The critical size of \(\sim\)119 nm rendered the aluminum surface superhydrophobic with three layers of coating using as-prepared nanoparticles suspended solution. On the other hand seven layers are required for a 50 vol.% diluted solution to achieve superhydrophobicity. In both the cases, water contact angles were more than 150\({}^{\circ}\), and contact angle hysteresis was less than 2\({}^{\circ}\). The authors considered that their coatings possessed self-cleaning properties. When applied on other substrates, like silicon or glass, superhydrophobicity is obtained by tuning the number of layers of deposition. The \(\alpha\),\(\omega\)-dialkoxyfluoropolyethers (DA-FPEs) prepared and characterized by [PERSON] and coworkers [3] in their contribution: _An Environmentally Friendly Class of Fluoropolyether:_\(\alpha\),\(\omega\)-_Dialkoxyfluoropolyethers_ have been developed as a new class of environmentally friendly hydrofluoroethers (HFEs) with multiple uses; suitable as solvents, long-term refrigerants, cleaning fluids, and heat transfer fluids. Synthetic methodologies for DA-FPEs described here consist of radical-initiated oxypolymerization of olefin, peroxy-elimination reaction in peroxididic perfluoropolyethers (PFPE) and further chemical modification of \(\alpha\),\(\omega\)-diacylglycerolfluoride PFPE. Physical properties of selected \(\alpha\),\(\omega\)-dimethoxyyl fluoropolyethers have been evaluated and compared with analogous hydrofluoropolyethers having -OCF\({}_{2}\)H as end-groups. The rationalization of the physical properties of these hybrid polymers is quite challenging. The highest boiling points are those of DM-FPEs, the intermediates are HFEs and the lowest ones are PFPEs. The above-mentioned result reflects the typical low intermolecular interactions of perfluorinated compounds. Partially fluorinated ethers, such as HFEs and DM-FPEs (\(\alpha\),\(\omega\)-dimethoxyylfluoropolyethers), display higher boiling temperatures and this is indicative of greater intermolecular polar interactions. Comparison of three similar fluoromethylethers, CF\({}_{3}\)OCF\({}_{3}\) (b.p. 214 K; \(\mu\) = 0.49 D), CF\({}_{2}\)HOCF\({}_{3}\) (b.p. 238 K, \(\mu\) = 1.18 D) and CH\({}_{3}\)OCF\({}_{3}\) (b.p. 250 K, \(\mu\) = 2.56 D) when contrasted to dimethyl ether, CH\({}_{3}\)OCH\({}_{3}\) (b.p. 249K, \(\mu\) = 1.30 D) the dipole moments really tell the story of the degree of polar interactions due to the presence of fluorine atoms. Interestingly, it is known that the presence of oxygen in PFPE impacts on chain flexibility but not on molecular polarity when compared with perfluoroalkyl analogues. Therefore, the glass transition temperature was found to decrease as the oxygen to carbon ratio was increased, maintaining a low cohesive energy density comparable with that of perfluoroalkanes. The progressive substitution of fluorine atoms with hydrogen in the methoxy end caps was found to lead to a stronger dipole and, consequently, to an increase of the boiling point. The boiling point differences between PFPEs and HFEs and between PFPEs and DM-FPEs are not constant but decrease continuously withthe chain length.