Experimental Study On Injection Molding Of PDMS Microfluidic Chip

In order to prepare microfluidic chips with excellent performance,the injection molding process,surface modification process and chip bonding process of poly two methyl siloxane(PDMS)substrate were studied in this paper.The main research works and achievements are as follows:l.we studied the mechanical properties of different formulations,the effects of molding parameters,such as injection pressure,holding time,and formulation on the molding efficiency of products.The PDMS substrate was made by injection molding.The process mainly includes the machining with microstructural core and the forming of PDMS substrate.First,the size of the micro structure is designed,and the metal mold core is made by the electric spark technology.PDMS and curing agent were mixed according to the proportion of 7.5:1.After injection molding,a certain time was cured at 100 C,and the PDMS substrate was removed.Scanning electron microscopy(SEM)was used to characterize the structure and surface morphology.The results show that the PDMS substrate based on convex microchannel template has simple forming process and many defects.2.The UV modification method of PDMS substrate was studied.By measuring the contact angle of products,the technological parameters of UV modification were established,and the modification mechanism was also discussed.3.The PDMS substrate and the cover were modified by UV,and the PDMS microfluidic chip was bonded.The strength of the PDMS chip with successful bonding is tested.The results show that the bonding strength of the PDMS hybrid microfluidic chip is greater than that of 0.88MPa,and that of the all PDMS microfluidic chip is about 0.23MPa.4.A series of tests were carried out on the products(the integrity,hydrophilicity and transparency)of the products.It was found that the chip channels made by this method had good integrity and good transmittance.The simulation of chip using COMSOL Multiphysics simulation software that can generate process parameters of droplets in the flow passage,the process parameters of simulated experiments were carried out to verify the function of sealing the chip,verified the microfluidic chip can generate droplets through this method made.