Hydrophobization of cotton fabric with silanes with different substituents

In this paper hydrophobization of cotton fabric with a range of silanes, differing in number of chlorine atoms and in other substituents, was explored. The fabric modification was carried out in silane solutions in anhydrous toluene and in n-hexane. Water contact angles were measured to characterize hydrophili/phobicity of the modified fabrics. Surfaces of the fibers were analyzed using SEM, EDS and ATR-FTIR. Treatment with dichlorodimethylsilane, dichloro(methyl)phenylsilane, 3-chloropropylmethyldichlorosilane and (3,3,3-trifluoropropyl)dichloromethylsilane resulted in hydrophobization, whereas trimethylchlorosilane and 3-aminopropyl(diethoxy)methylsilane were inefficient. Mechanisms of coating with the silanes were proposed. Dielectric spectroscopy of the modified fabric demonstrated that resistance was sensitive to efficiency of reactions removing water from the cotton fibers.