The objectives of this study are to observe the effects of the introduction of polydimethylsiloxane (PDMS) on the hydration and degradation of aliphatic polyesters in water, such as poly(ε-caprolactone) (PCL). The mechanism of PCL degradation in water is well known, and PDMS is a nonbiodegradable and hydrophobic polymer. The ligation of these two polymers should allow the synthesis of new polymers with hybrid properties in terms of degradation and surface energy. The deterioration in water should be controlled by the ratio of each polymer. The triblock copolymers were synthesized through ring opening polymerization with stannous octanoate as the catalyst. A film of each copolymer was prepared and immersed in distilled water to study their aging. Kinetic results of hydration and degradation show that the addition of PDMS on PCL does not change the profiles of hydration and degradation. But the variation of the structure of the triblock (molecular weight or ratio of each block) allows to increase or decrease the rate of hydration, so as to control its degradation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40431.