Novel low refractive index fluorinated polymers were prepared from perfluoroalkylsilane and polyethoxysiloxane by a sol-gel technique for antireflection applications. Perfluoroalkylsilane having low refractive index fluoroalkyl groups incorporate polyethoxysiloxane by condensation of their siloxane groups to improve the adhesion and hardness of the fluorinated polymers. Syntheses and characteristics of the fluorinated polymers were investigated by the studies of FTIR, GPC, UV-vis, ellipsometry, and mechanical tests. The experimental results reveal that the refractive index and hardness of the coating using the optimal fluorinated polymer were about 1.39 and 3H, respectively, which meet the requirements in practical applications. It was also found that the fluorinated polymer made from polyethoxysiloxane had a better hardness than that made from tetraethyl orthosilicate. (C) 2010 Wiley Periodicals, Inc. I Appl Polym Sci 118: 1615-1619, 2010