Polydimethylsiloxane（ PDMS） is currently the most widely used substrate material in microfluidic chip

but

microfluidic chip with this material has some problems in application

such as volatile solvent and difficulty in long term testing. To solve these problems

a simple and high-efficient fabrication method is developed to make‘glass-PDMS film-glass’（ G—P—G） sandwich structure microfluidic chip. This method uses polyester（ PET） film as carrier to transfer and handle structured PDMS film

and then the PDMS film is sandwiched between two glasses through the plasma treatment

to form sandwich structure chip

it has the feature of low solvent evaporation because of low permeability of glass material. Low solvent evaporation characteristics of the sandwich chip is validated through protein crystallization experiment.