As the feature size of next-generation microprocessors decreases, the need for low-dielectric constant (low-k) materials with high mechanical strength is an increasing concern.  Many potential porous materials take advantage of the low k value of air, which is about 1, but they are often amorphous in nature and thus lack mechanical strength.  Porous zeolites, however, are highly crystalline and have a high elastic modulus while retaining the low k values of amorphous porous silica materials.[1]  Since water has a high k value, moisture adsorption is a serious concern for all porous low-k materials.  Consequently, along with low k and high elastic modulus values, hydrophobicity is becoming an increasingly important parameter.[2]^,[3]  To combat this problem, post-spin-on silylation treatments with chlorotrimethylsilane and hexamethyldisilazane have been performed, and pure-silica zeolite (PSZ) MFI has been functionalized with methyltrimethoxysilane.[4]  Here, we report an organic functionalized pure-silica zeolite with an MFI-type structure prepared through a direct-synthesis method by adding a fluorinated silane to the synthesis solution, and the added fluorine functionality increased the hydrophobicity of the zeolite.  The zeolite was characterized by x-ray diffraction, ²⁹Si solid-state nuclear magnetic resonance spectroscopy, nitrogen adsorption, FT infrared spectroscopy, and thermogravimetric analysis.  Spin-on films from the nanoparticle suspension exhibited higher water contact angles than pure-silica zeolite MFI films, and the zeolite powders had low water content.