TS‐1 molecular sieves were synthesized and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and UV–Vis spectroscopy. Results showed that the morphology, crystallinity, and purity of TS‐1 were closely related to the Ti/Si ratio, crystallization time, crystallization temperature, and calcination time. The TS‐1 particles were incorporated into polydimethylsiloxane to form mixed matrix membranes (MMMs), and these MMMs were first used to separate ethanol/water mixtures via pervaporation. The MMMs with 50 wt% TS‐1 (Ti/Si ratio of 0.02) loading showed the highest separation factor of 14.1 for 5 wt% ethanol feed concentration at 50°C. POLYM. ENG. SCI., 56:583–589, 2016. © 2016 Society of Plastics Engineers