A series of nine films were prepared via phenol-catalyzed thermal crosslinking reactions of 1,9-bis[glycidyloxypropyl]pentasiloxanes {1,9-bis[glycidyloxypropyl]decamethylpentasiloxane (I), 1,9-bis[glycidyloxypropyl]-3,5,7-tris(3',3',3'-trifluoropropyl)heptameth ylpentasiloxane (II), and 1,9-bis[glycidyloxypropyl]-3,5,7-tris(1'H,1'H,2'H, 2'H-perfluorooctyl)heptamethylpentasiloxane (III)} with alpha, omega-diaminoalkanes [1,6-diaminohexane (a), 1,8-diaminooctane (b), and 1,12-diaminododecane (c)]. The crosslink density was controlled by the choice of a-c. The cure behavior of I-III with a-c was studied with differential scanning calorimetry. The mechanical properties of the films were determined by dynamic mechanical thermal analysis. Their thermal stability was analyzed by thermogravimetric analysis. The surface properties of the films were evaluated with static contact-angle measurements. These films represented a novel class of epoxies with an unusual combination of properties: high flexibility (low glasstransition temperature), good thermal stability, and hydrophobic surfaces. (C) 2004 Wiley Periodicals, Inc.