Investigation on physico-chemical and electrochemical properties of fluoropolyether coatings

A series of model coatings made of perfluoropolyether (PFPE) and different isocyanurate blocks were prepared and investigated through differential scanning calorimetry (DSC), dynamic-mechanical analysis (DMA) and electrochemical impedance spectroscopy (EIS) measurements. Phase transitions, dielectric constants and water permeability were also evaluated. The result was that the molecular weight of PFPE segment as well as the chemical nature of isocyanurate block influence the properties of the final urethane coatings. In general, polyphasic polyurethane networks are formed, but in some cases more homogeneous structures are promoted by the use of low molecular weight PFPE segments. Lower water permeabilities are obtained by the higher T-g and harder IPDI containing coatings. Very efficient barrier behaviour even at long exposure are shown by coatings made with lower molecular weight PFPE macromers. (C) 2002 Elsevier Science B.V. All rights reserved.