New alkylated and perfluoroalkylated phosphonic acids: Synthesis, adhesive and water-repellent properties on aluminum substrates

Abstract This paper describes the synthesis of phosphonic acids (R–S–(CH 2 ) 2 –PO(OH) 2 ) containing a perfluoroalkylated chain (R = C 6 F 13 –(CH 2 ) 2 , C 8 F 17 –(CH 2 ) 2 ) or an alkyl group (R = C 12 H 25 , C 18 H 37 ). These compounds, obtained in excellent yield by telomerization of vinyl phosphonic acid in the presence of alkylated or perfluorinated mercaptans used as transfer agents, were characterized by 1 H, 19 F and 31 P nuclear magnetic resonance. Thermal characterization by differential scanning calorimetry (DSC) showed the presence of mesophases for compounds containing C 8 F 17 and C 18 H 37 end groups. A lamellar structure with a layered or bilayered organization was identified by small angle X-ray scattering (SAXS). Adhesion of these compounds on aluminum surfaces is improved by the presence of phosphonic groups. Hydrophobic properties of coated aluminum surfaces are enhanced by fluorinated groups.