Preparation of double emulsions in glass microchips is still challenging because of the difficulty in spatially patterning microchannel wettability.In this work,a partially hydrophilic and partially hydrophobic glass microchip was fabricated for producing water-in-oil-in-water(W/O/W)double emulsions.An alkylsilane self-assembling and UV-photodegrading technique was employed to selectively pattern the wettability of glass microchannels.With the fabricated glass microchip,presenting high wettability contrast,stable monodisperse W/O/W double emulsions were successfully prepared.The prepared double emulsions had narrow size distributions with coefficient of variation values less than 8%.Moreover,both the size and the number of the inner droplets could be controlled by adjusting the flow rates.